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Morphological and physiological responses of two coffee progenies to soil water availability
Abstract
Drought is a major environmental constraint affecting growth and production of coffee. The effects of water supply on growth, biomass allocation, water relations, and gas exchange in two coffee progenies representing drought-tolerant (Siriema) and drought-sensitive (Catucaí) genotypes were compared. They were grown in 12-L pots until 4-months old, when they were submitted to two watering treatments for 60 d: plants receiving either 100% transpired water (control plants) or a fraction (about 40%) of the amount of water transpired by control plants (drought-stressed plants). Under control conditions, Siriema grew faster than Catucaí. Regardless of the watering regimes and progenies, relative growth rate (RGR) was positively correlated both with net assimilation rate (NAR) and long-term water-use efficiency (WUE), but not with differences in biomass allocation. Both progenies responded to drought stress through (i) similar decreases in both RGR and NAR with marginal, if any, changes in allocation; (ii) decreases in leaf water potential, which occurred to a greater extent in Catucaí than in Siriema, even though they have showed similar abilities to adjust osmotically and elastically; (iii) similar reductions in net photosynthesis due mainly to nonstomatal factors; and (iv) decreases in transpiration rate coupled with increased long-term WUE. However, the lower transpiration rate and the higher long-term WUE as found in Siriema relative to Catucaí under control conditions persisted under drought conditions. Overall, the major differences between these progenies were largely associated with differences in plant water use, which was likely related to the improved water status of Siriema. The possible implications of selecting coffee genotypes for high WUE are discussed.
... Drought stress is well known to reduce the growth and physiological processes of C. arabica [59,75]. Under drought, there is a decline in turgor pressure that leads to a reduction in cell division, elongation, and expansion, which then decreases growth and development, gas exchange, and morphological, molecular, and other biochemical activities [76]. ...
... Tagliavini et al. [88] and Hussain et al. [89] reported that drought-tolerant genotypes develop deeper and more developed root systems to support the plants in acclimatizing to a wide range of drought stress conditions. When drought-tolerant plants are grown under water deficit conditions, developmental changes and maximization of root number, length, density, volume, size, and diameter are more evident than for drought-sensitive plants [27,75]. Osakabe et al. [90] and Smith and De Smet [91] stated that the elongation of the root is a vital strategy to maximize the retention of soil water content, and nutrient absorption to improve the plant root-to-shoot proportion, and subsequently reducing the plant biomass. ...
... As a result of the reduction of shoot and root growth and development under drought stress conditions, the reduction of fresh biomass and dry biomass was observed but in the relatively tolerant genotypes (Ca74112 and Ca74110), mass decrease was significantly lower than the sensitive genotypes (Ca754 and CaJ-19). The reduction of biomass under drought stress conditions in four of the genotypes was in line with the results obtained by Dias et al. [75] and Poorter et al. [95]. ...
The coffee plant is highly susceptible to drought, and different genotypes exhibit varying degrees of tolerance to low soil moisture. The goal of this work was to explore the interrelation between seed traits and germination events, growth patterns, and physiological responses of coffee genotypes, aiming to identify significant associations that may facilitate the selection of coffee genotypes exhibiting enhanced drought tolerance and yield potential. Two consecutive experiments were conducted to examine the impact of these factors. In the first experiment, germination performance was examined for three groups of coffee genotypes: relatively tolerant (Ca74140, Ca74112, and Ca74110), moderately sensitive (Ca74158, Ca74165, and CaJ-21), and sensitive (Ca754, CaJ-19, and CaGeisha). The subsequent experiment focused on the growth and physiological responses of two relatively tolerant (Ca74110 and Ca74112) and two sensitive (CaJ-19 and Ca754) genotypes under drought stress condition. The relatively tolerant genotypes showed quicker and more complete germination compared to other groups. This was associated with higher moisture content, higher seed surface area to volume ratio, and higher coefficient of velocity of germination, coefficient of variation of germination time, and germination index. Additionally, the relatively tolerant genotypes showed higher seedling vigor. The results of the second experiment demonstrated superior growth performance in relative tolerant genotypes compared to the sensitive groups. Young coffee plants belonging to relatively tolerant genotypes exhibited higher growth performance than the sensitive genotypes, with a net assimilation rate strongly correlated to relative water content, leaf number, stomatal conductance, and chlorophyll-a. In addition, a strong correlation was exhibited between the growth of young coffee plants and the surface area to volume ratio of the seeds, as well as the germination percentage. The seedling vigor index showed a strong correlation with net assimilation rate, chlorophyll content, seedling growth, and cell membrane stability. Furthermore, principal component analysis illustrated distinct clustering of genotypes based on their germination and growth-physiological performance. Overall, the findings of this study suggest that seed traits, germination, and post-germination events are integral factors in determining drought tolerance and sensitivity, as well as the growth and physiological responses of adult coffee plants.
... Drought stress is well known to reduce the growth and physiological processes of C. arabica [73]. Under drought, there is a decline in turgor pressure that leads to a reduction in cell division, elongation, and expansion, which then decreases growth and development, gas exchange, and 5 morphological, molecular, and other biochemical activities [74]. ...
... Tagliavini et al. [86] and Hussain et al. [87] reported that drought-tolerant genotypes develop deeper and more developed root systems to support the plants to acclimatize to a wide range of drought stress conditions. When drought-tolerant plants are grown under water deficit conditions, developmental changes and maximization of root number, length, density, volume, size, and diameter are more evident than for drought-sensitive plants [73]. Osakabe et al. [88], and Smith and De Smet [89] stated the elongation of the root is a vital strategy to maximize the retention of soil water content, and nutrient absorption to improve the plant root-to-shoot proportion, and subsequently reducing the plant biomass. ...
... As a result of the reduction of shoot and root growth and development under drought stress conditions, the reduction of fresh biomass and dry biomass was observed but in the relatively tolerant genotypes (Ca74112 and Ca74110)mass decrease was significantly lower than the sensitive genotypes (Ca754 and CaJ- 19). The reduction of biomass under drought stress conditions in four of the genotypes was in line with the results obtained by Dias et al. [73] and Poorter et al. [93]. 6 DaMatta and Ramalho [33], and DaMatta [94], reported the reduction of fresh and consequently dry weight in coffee plants when they were subjected to drought stress. ...
The coffee plant is highly susceptible to drought, and different genotypes exhibit varying degrees of tolerance to low soil moisture. The current study aims to investigate the connection between drought tolerance and sensitivity in terms of seed traits, germination, and post-germination events, and their influence on the growth and physiology of young coffee plants. Two consecutive experiments were conducted to examine the impact of these factors. In the first experiment, germination performance was examined for three groups of coffee genotypes: relatively tolerant (Ca74140, Ca74112, and Ca74110), moderately sensitive (Ca74158, Ca74165, and CaJ-21), and sensitive (Ca754, CaJ-19, and CaGeisha). The subsequent experiment focused on the growth and physiological responses of two relatively tolerant (Ca74110 and Ca74112) and two sensitive (CaJ-19 and Ca754) genotypes under drought stress condition. The relatively tolerant genotypes showed quicker and more complete germination compared to other groups. This was associated with higher moisture content, higher seed surface area to volume ratio, and higher coefficient of velocity of germination, coefficient of variation of germination time, and germination index. Additionally, the relatively tolerant genotypes showed higher seedling vigor. The results of the second experiment demonstrated superior growth performance in relative tolerant genotypes compared to the sensitive groups. Young plants of coffee belonging to relatively tolerant genotypes exhibited higher growth performance than the sensitive genotypes, with a net assimilation rate strongly correlated to relative water content, leaf number, stomatal conductance, and chlorophyll-a. In addition, a strong correlation was exhibited between the growth of young coffee plants and the surface area to volume ratio of the seeds, as well as the germination percentage. The seedling vigor index showed a strong correlation with net assimilation rate, chlorophyll content, seedling growth, and cell membrane stability. Furthermore, principal component analysis illustrated distinct clustering of genotypes based on their germination and growth-physiological performance. Overall, the findings of this study suggest the importance of seed traits, germination, and post-germination events are integral factors in determining drought tolerance and sensitivity, as well as the growth and physiological responses of adult coffee plants.
... This is because water needs among cocoa genotypes as reported by Ayegboyin and Akinrinde [15] vary. More so report from research conducted by Dias et al. [16] identify genotypes that possess character for good growth, high yield and efficient water use efficiency (WUE) which he said is important for breeding. Mng'omba et al. [5] in their research conclude that sustainability of water uses, and its cost implication is paramount in commercial nurseries. ...
... However, the 8 th WAS, CRINTc 5 variety having 100 ml watering rate had significantly the highest value of 5.03 cm, while the least mean value of 3.54 cm was recorded in the F3 Amazon variety when the least watering rate of 50 ml was applied. Furthermore, 150 ml of watering significantly enhanced an increased stem girth growth of 12 th WAS but at [16][17][18][19][20] th WAS stem girth becomes significantly static among the different cocoa varieties irrespective of the levels of water applications. However 150 ml watering rate applied to all the varieties did not give the thickest stem girth at 16 Table 5, the production of leaves was not significantly (p>0.05) ...
... Furthermore, 150 ml of watering significantly enhanced an increased stem girth growth of 12 th WAS but at [16][17][18][19][20] th WAS stem girth becomes significantly static among the different cocoa varieties irrespective of the levels of water applications. However 150 ml watering rate applied to all the varieties did not give the thickest stem girth at 16 Table 5, the production of leaves was not significantly (p>0.05) enhanced. ...
Cocoa genotypes exhibiting different responses to water and watering rates to growth parameters necessitate this study. Seedlings were raised from cocoa hybrids genotypes (CRIN Tc1 – 8) and F3 Amazon. The seeds after 4 days of sowing were subjected to 3 watering rates of 50 ml, 100 ml and 150 ml applied once every two days and arranged in a CRD design between December 2020 - May 2021 at Cocoa Research Institute of Nigeria (CRIN) Ibadan Nursery. Data collected include the percentage of germination at 2-4 weeks after sowing (WAS), growth parameter (plant height, girth, leaf area, number of leaves), and destructive sampling (fresh and dry weight of shoot weight, root weight and Taproot length) which were statistically analyzed with SAS tools. The watering rates had no significant effect on cocoa seedling emergence date. Least plant heights were observed when 50ml watering rate was applied on CRINTc-1 (25.00cm), CRINTc-2 (26.53cm), CRINTc-4 (24.10 cm), CRINTc-6 (27.52cm) and CRINTc-8 (28.75cm) at 20WAS. Stem girth, number of leaves and fresh root weight were not significantly enhanced by the watering levels on the cocoa genotypes. The result also reveals that the dry shoot weight was greater than the dry root weight of their corresponding treatments. The 3 watering levels had no considerable effect on the emergence of the cocoa genotypes but influenced the morphological traits, fresh and dry weight of the shoot and root parameters of the cocoa genotypes. 100 ml watering rate applied on the cocoa genotypes performed more appreciably followed by 150 ml.
... Among some 90 species of the genus Coffea, C. arabica L. (Arabica coffee) and C. canephora Pierre (Robusta coffee) economically dominate the world coffee trade, being responsible for about 99% of world bean production (Da Matta and Ramalho, 2006). Arabica coffee accounts for more than 62% of the world coffee production (Dias et al., 2007) and 90% of the world coffee market (Worku and Astatkie, 2010). Robusta coffee accounts for the rest. ...
... Biochemical traits such as improved tolerance of oxidative stress (Lima et al., 2002;Pinheiro et al., 2004) and ability to maintain assimilate export (Praxedes et al., 2005) are also considered important. Drought-tolerant coffee genotypes are able to maintain higher tissue water potential and water use efficiency than drought-sensitive ones under water-deficit conditions (DaMatta, 2004;Dias et al., 2007). Such differences are even more evident in the field, where the development of the root system is much less restricted (Da Matta et al., 2003). ...
... Arabica and Robusta) may also differ in morphological and/or physiological mechanisms that allow them to produce considerably well under limited water supply (Da Matta, 2004). Arabica coffee genotypes have been found to differ in drought adaptation mechanisms such as stomata control and soil water extraction efficiency (DaMatta and Ramalho, 2006), plant water use and biomass allocation to the stems and leaves (Dias et al., 2007) and tissue water potential (DaMatta, 2004). On the other hand, studies on Robusta coffee showed deeper root system (Pinheiro et al., 2005) and larger root dry mass in drought tolerant clones than in drought sensitive ones (DaMatta and Ramalho, 2006). ...
... La menor disponibilidad lumínica, debido a que en el momento de la evaluación el cultivo estaba bajo un sombrío transitorio de Tephrosia, fue la razón por la cual la fotosíntesis (An) en La Argentina presentó un menor valor (29%) con respecto a Campoalegre (Figura 4a), esto debido a que existe una relación directa entre la máxima tasa fotosintética que pueden alcanzar las hojas de café y el nivel de luminosidad bajo el cual crecieron y/o se adaptaron (Franck & Vaast, 2009). En este sentido, el mayor número de unidades SPAD (10%) registrado en La Argentina (Figura 4e) también fue resultado de la disponibilidad lumínica, puesto que las hojas aclimatadas a una menor cantidad de luz lograron mayores contenidos de clorofila (medida indirectamente por las unidades SPAD), dada la necesidad de las hojas de café por capturar más luz (Matos et al., 2009 El uso eficiente del agua indica que las plantas en Campoalegre crecieron sujetas a una menor disponibilidad de agua (52%) en relación con las plantas en La Argentina (Figuras 4c, 5 y 6), debido a que el valor del UEA se incrementa cuando el déficit hídrico que experimenta la planta es mayor (Dias et al., 2007) (Figuras 5 y 6) . Esto tiene concordancia con la menor precipitación registrada en el municipio de Campoalegre respecto a La Argentina. ...
... La producción de café (Prod.) es afectada al disminuir la disponibilidad de agua, debido a que en compensación al estrés hay una mayor translocación de foto-asimilados hacia las raíces que a la parte aérea de la planta (Dias et al., 2007). Campoalegre y La Argentina son localidades de cosecha de primer semestre; sin embargo, las condiciones ambientales predominantes en el 2020 originaron un patrón atípico con dos picos importantes, uno en primer y otro en segundo semestre (Figura 8). ...
... UEA, CV p vs. UEA). Esta correlación se explica puesto que a menor disponibilidad de agua se incrementan los valores de UEA (Dias et al., 2007), y como resultado, la floración durante el semestre floral es más concentrada (Arcila & Jaramillo, 2003). Por otra parte, la alta asociación entre la sincronía y la magnitud de la floración (r i vs. CV p ) y en mayor grado entre la magnitud de la floración individual y poblacional (CV p vs . ...
En la segunda fase del proyecto (2019-2021) se dio continuidad a tres investigaciones, cuyos resultados están descritos en el presente libro. En esta entrega se describen los logros alcanzados en la caracterizaron morfológica, agronómica y fisiológica, en dos ambientes contrastantes de la caficultura, de 50 accesiones de la Colección Colombiana de Café, que representan la diversidad que está disponible para el desarrollo de variedades de Coffea arabica, y que se denomina Colección Núcleo. Se identificaron accesiones etíopes silvestres que se destacan por su buen comportamiento bajo las condiciones experimentales evaluadas, con altos niveles productivos, perfiles sensoriales diferenciales, con potencial para ser incluidas dentro del Programa de Mejoramiento Genético de Cenicafé como progenitores de futuras variedades mejoradas. Fruto de las investigaciones realizadas durante la vigencia del proyecto, se seleccionaron 13 líneas mejoradas, resistentes a la roya, con excelentes características agronómicas, calidad física del grano y calidad en taza catalogada como especial, que pueden entrar a conformar las variedades comerciales vigentes. Así mismo, se establecen las recomendaciones para aquellos municipios cafeteros del departamento del Huila donde es necesario realizar el ajuste del sistema de producción, lo que significa cambiar de una caficultura a libre exposición solar a una caficultura bajo sombra. Finalmente, se evidencia cómo la implementación del número de plantas por hectárea ajustado a las condiciones propias del sistema productivo, así como la adopción de las prácticas de manejo agronómico adecuadas tienen un efecto marcado sobre la productividad y, por ende, sobre la rentabilidad del negocio cafetero.
... Exposing coffee plants continuously to high temperature coupled with precipitation stress (water deficit in wet season and excess during dry season) declines its productivity (Damatta and Ramalho 2006;Dias et al. 2007;Belachew and Teferi 2015;Craparo et al. 2015;Moat et al. 2017). For example, if expected higher temperatures occur during sensitive stages of the crop such as flowering or fruit setting, yield will be adversely affected (Bote and Struik 2011;Jassogne et al. 2013). ...
... For example, if expected higher temperatures occur during sensitive stages of the crop such as flowering or fruit setting, yield will be adversely affected (Bote and Struik 2011;Jassogne et al. 2013). In extreme cases, high temperatures occur at blossoming stage with a prolonged dry season and this may cause the abortion of crop flowers (Damatta and Ramalho 2006;Dias et al. 2007;Camargo 2010). Also, low temperatures coupled with water deficit affect the crop's photosynthesis by reducing stomata conductance and carbon metabolism (Bote and Struik 2011;Kufa and Burkhardt 2015). ...
... Also, low temperatures coupled with water deficit affect the crop's photosynthesis by reducing stomata conductance and carbon metabolism (Bote and Struik 2011;Kufa and Burkhardt 2015). Moreover, an increase in rain levels during the flowering stage will disturb the crop's fruit setting and filling, thereby declining its productivity and quality (Damatta and Ramalho 2006;Dias et al. 2007;Bote and Struik 2011;Jassogne et al. 2013;Jayakumar et al. 2016;Moat et al. 2017). ...
Your article is protected by copyright and all rights are held exclusively by Springer Nature B.V.. This e-offprint is for personal use only and shall not be self-archived in electronic repositories. If you wish to self-archive your article, please use the accepted manuscript version for posting on your own website. You may further deposit the accepted manuscript version in any repository, provided it is only made publicly available 12 months after official publication or later and provided acknowledgement is given to the original source of publication and a link is inserted to the published article on Springer's website. The link must be accompanied by the following text: "The final publication is available at link.springer.com". Using the yield-SAFE model to assess the impacts of climate change on yield of coffee (Coffea arabica L.) under agroforestry and monoculture systems Abstract Ethiopia economy depends strongly on Coffea arabica production. Coffee, like many other crops, is sensitive to climate change and recent studies have suggested that future changes in climate will have a negative impact on its yield and quality. An urgent development and application of strategies against negative impacts of climate change on coffee production is important. Agroforestry-based system is one of the strategies that may ensure sustainable coffee production amidst likelihood future impacts of climate change. This system involves the combination of trees in buffer extremes thereby modifying microclimate conditions. This paper assessed coffee production under: (1) coffee monoculture and (2) coffee grown using agroforestry system, under: (a) current climate and (b) two different future climate change scenarios. The study focused on two representative coffee growing regions of Ethiopia under different soil, climate and elevation conditions. A process-based growth model (yield-SAFE) was used to simulate coffee production for a time horizon of 40 years. Climate change scenarios considered were: representative concentration pathways (RCP) 4.5 and 8.5. The results revealed that in monoculture systems, the current coffee yields are between 1200 and 1250 kg ha-1 year-1 , with expected decrease between 4-38 and 20-60% in scenarios RCP 4.5 and 8.5, respectively. However, in agroforestry systems, the current yields are between 1600 and 2200 kg ha-1-year-1 , the decrease was lower, ranging between 4-13 and 16-25% in RCP 4.5 and 8.5 scenarios, respectively. From the results, it can be concluded that coffee production under agroforestry systems has a higher level of resilience when facing future climate change and reinforce the idea of using this type of management in the near future for adapting climate change negative impacts on coffee production.
... Studies by DaMatta et al. [28] and Wei et al. [29] have that drought stress on diminishes shoot and root growth in coffee and Lycium barbarum plants, respectively. However, previous research by Chekol et al. [7] and Dias et al. [30] suggest that in tolerant genotypes, enhanced growth responses are linked to water conservation mechanisms that enable coffee plants to sustain cell division and elongation processes. Studies by Caine et al. [25] and Xiong et al. [31] on rice and oak plants, respectively, also support the notion that limited water availability triggers metabolic responses favoring cellular division. ...
... Drought stress often leads to decreased photosynthesis assimilation rates and stomatal conductance, and can affect gaseous exchange parameters [26,31]. Similarly, tolerant coffee genotypes exhibited better physiological performances in these parameters compared to sensitive genotypes under drought stress [7,30]. The reduction in photosynthesis rate under drought is usually associated with stomatal closure and decreased internal CO 2 concentrations, impacting CO 2 fixation and pigment synthesis [9,37,38]. ...
Understanding the impact of drought stress on Arabica coffee physiology and metabolism is essential in the pursuit of developing drought-resistant varieties. In this study, we explored the physiological and metabolite changes in coffee genotypes exhibiting varying degrees of tolerance to drought-namely, the relatively tolerant Ca74110 and Ca74112, and the sensitive Ca754 and CaJ-19 genotypes-under well-watered conditions and during terminal drought stress periods at two time points (0 and 60 days following the onset of stress). The metabolite profiling uncovered significant associations between the growth and the physiological characteristics of coffee genotypes with distinct drought tolerance behaviors. Initially, no marked differences were observed among the genotypes or treatments. However, at the 60-day post-drought onset time point, notably higher shoot growth, biomass, CO2 assimilation, pigments, and various physiological parameters were evident, particularly in the relatively tolerant genotypes. The metabolite profiling revealed elevations in glucose, maltose, amino acids, and organic acids, and decreases in other metabolites. These alterations were more pronounced in the drought-tolerant genotypes, indicating a correlation between enhanced compatible solutes and energy-associated metabolites crucial for drought tolerance mechanisms. This research introduces GC-MS-based metabolome profiling to the study of Ethiopian coffee, shedding light on its intricate responses to drought stress and paving the way for the potential development of drought-resistant coffee seedlings in intensified agro-ecological zones.
... Studies by DaMatta et al. [28] and Wei et al. [29] have that drought stress on diminishes shoot and root growth in coffee and Lycium barbarum plants, respectively. However, previous research by Chekol et al. [7] and Dias et al. [30] suggest that in tolerant genotypes, enhanced growth responses are linked to water conservation mechanisms that enable coffee plants to sustain cell division and elongation processes. Studies by Caine et al. [25] and Xiong et al. [31] on rice and oak plants, respectively, also support the notion that limited water availability triggers metabolic responses favoring cellular division. ...
... Drought stress often leads to decreased photosynthesis assimilation rates and stomatal conductance, and can affect gaseous exchange parameters [26,31]. Similarly, tolerant coffee genotypes exhibited better physiological performances in these parameters compared to sensitive genotypes under drought stress [7,30]. The reduction in photosynthesis rate under drought is usually associated with stomatal closure and decreased internal CO 2 concentrations, impacting CO 2 fixation and pigment synthesis [9,37,38]. ...
Understanding the impact of drought stress on Arabica coffee physiology and metabolism is essential in the pursuit of developing drought-resistant varieties. In this study, we explored the physiological and metabolite changes in coffee genotypes exhibiting varying degrees of tolerance to drought—namely, the relatively tolerant Ca74110 and Ca74112, and the sensitive Ca754 and CaJ-19 genotypes—under well-watered conditions and during terminal drought stress periods at two time points (0 and 60 days following the onset of stress). The metabolite profiling uncovered significant associations between the growth and the physiological characteristics of coffee genotypes with distinct drought tolerance behaviors. Initially, no marked differences were observed among the genotypes or treatments. However, at the 60-day post-drought onset time point, notably higher shoot growth, biomass, CO2 assimilation, pigments, and various physiological parameters were evident, particularly in the relatively tolerant genotypes. The metabolite profiling revealed elevations in glucose, maltose, amino acids, and organic acids, and decreases in other metabolites. These alterations were more pronounced in the drought-tolerant genotypes, indicating a correlation between enhanced compatible solutes and energy-associated metabolites crucial for drought tolerance mechanisms. This research introduces GC-MS-based metabolome profiling to the study of Ethiopian coffee, shedding light on its intricate responses to drought stress and paving the way for the potential development of drought-resistant coffee seedlings in intensified agro-ecological zones.
... Studies by DaMatta et al. [36] and Wei et al. [37] have highlighted the impact of drought stress on diminishing shoot and root growth in coffee and Lycium barbarum plants, respectively. However, previous research by Chekol et al. [7] and Dias et al. [38] suggest that in tolerant genotypes, enhanced growth responses are linked to water conservation mechanisms that enable coffee plants to sustain cell division and elongation processes. Studies by Caine et al. [25] and Xiong et al. [39] on rice and oak plants, respectively, also support the 13 notion that limited water availability triggers metabolic responses favoring cellular division. ...
... Drought stress often leads to decreased photosynthesis assimilation rates, stomatal conductance, and transpiration rates, affecting gaseous exchange parameters [39,34]. Similarly, tolerant coffee genotypes exhibited better physiological performances in these parameters compared to sensitive genotypes under drought stress [7,38]. The reduction in photosynthesis rate under drought is usually associated with stomatal closure and decreased internal CO2 concentrations, impacting CO2 fixation and pigment synthesis [9,45,46]. ...
Understanding the impact of drought stress on Arabica coffee physiology and metabolism is essential in the pursuit of developing drought-resistant varieties. In this study, we explored the physiological and metabolite changes in coffee genotypes exhibiting varying degrees of tolerance to drought—namely, the relatively tolerant Ca74110 and Ca74112, and the sensitive Ca754 and CaJ-19—under well-watered conditions and during terminal drought stress periods over two-time intervals (0 and 60 days following the onset of stress). The Metabolites profiling conducted uncovered significant associations between growth and the physiological characteristics of coffee genotypes with distinct drought tolerance behaviors. Initially, no marked differences were observed among genotypes or treatments. However, at the 60-day post-drought onset, notable increases in shoot growth, biomass, CO2 assimilation, pigments, and various physiological parameters were evident, particularly in the relatively tolerant genotypes. Metabolite profiling revealed elevations in glucose, maltose, amino acids, organic acids, and decreases in other metabolites, more pronounced in drought-tolerant genotypes. These alterations were more pronounced in the drought-tolerant genotypes, indicating a correlation with enhanced compatible solutes and energy-associated metabolites crucial for drought tolerance mechanisms. This research introduces GC-MS based metabolome profiling to Ethiopian coffee, shedding light on the intricate responses to drought stress and paving the way for the potential development of drought-resistant coffee seedlings in intensified agro-ecological zones.
... Recently, climate change has generated increases in the intensity and severity of extreme scenarios, including prolonged drought, floods, and increasing heat waves (Fischer et al., 2016;Avila et al., 2020;Toral-Ju arez et al., 2021). Drought events are the main climatic limitation for the C. arabica crop because they gradually reduce the availability of water in the soil (to generate a water deficit), affecting important physiological processes in the plants (Dias et al., 2007;Dubberstein et al., 2020;Almeida et al., 2021). This situation is concerning in areas cultivated with coffee, particularly in regions susceptible to drought, where the use of irrigation is limited due to the little availability of water Avila et al., 2020). ...
... The decrease in the value of C pd -2.29 MPa reported in this study (Fig. 3a) showed that C. arabica plants may trigger a low elasticity of the cell wall and losses of turgor, as previously have been reported in the study of the authors Tounekti et al. (2018) and in C. arabica plants with similar values C pd between -1.5 and -2.5 MPa. Likewise, with decreases in C pd from -1.4 MPa, the decrease in leaf water content and hydraulic conductance of the plant have been confirmed, evidencing the detrimental effect of water deficit on the water absorption process in C. arabica plants (Dias et al., 2007;Miniussi et al., 2015;Tounekti et al., 2018). ...
In the coffee-growing areas of Colombia, the vulnerability of soils to conditions of water deficit has been determined and this limitation has been projected to increase its intensity and severity during extreme climatic scenarios, which constitute one of the factors limiting coffee production. The objective of this study was to evaluate the effect of prolonged water deficit conditions on the physiological performance of coffee plants cv. Castillo Ò. The evaluations were carried out in 13-month-old "Castillo Ò " variety plants established in a greenhouse which were subjected to two conditions: well-watered at field capacity and water deficit in the soil-applied through withholding the water supply for 40 days, using a completely randomized experimental design. Leaf water potential (C pd and C md), gas exchange, and chlorophyll fluorescence parameters (F v /F m and ETR) were measured. In the plants with water deficit, C pd and C md were decreased significantly. Five days after restricting the water supply, the g s was significantly reduced to 95% at the end of the experiment compared to plants without stress. The F v /F m and ETR parameters showed no sensitivity under the water deficit conditions. Plants under water deficit decreased A max by 81% , I sat by 61%, and R d by 50%, as compared to plants without stress. The transpiration and water-use efficiency decreased, while C i had a greater concentration in plants under water deficit. These results indicate the physiological performance coffee cv. Castillo Ò plants were significantly affect by prolonged conditions of soil water deficit and that the reductions in photosynthetic processes were related to stomatal limitations.
... Uganda has been reported to have substantial C. canephora diversity (Kiwuka, 2020;Kiwuka et al., 2021;Musoli et al., 2009;Ngugi & Aluka, 2019) which could be explored to identify functional diversity in regard to drought stress. But to our knowledge, intraspecific comparisons of drought-related traits in C. canephora have been limited to cultivated material (DaMatta et al., 2003;Dias et al., 2007;King'oro, 2014;Menezes-Silva et al., 2015;Pinheiro & Var, 2004;Silva et al., 2013). While the aforementioned studies give important insights into the morphological and physiological drivers of drought tolerance, exploration of the variation in drought tolerance across wild populations and potential correlations with climate need to be done. ...
... In our study, TNL and TLA were the most affected traits (Table 2) implying that genotypes responded to restricted-water mainly by minimizing transpirational water loss by reducing the number of leaves and leaf area. Differential reduction in leaf area as a response to drought stress has also been observed by other authors (DaMatta et al., 2003;Dias et al., 2007;King'oro, 2014;. Our current findings extend these observations to a wider range of genotypes including wild, feral and cultivated material. ...
Uganda lies within the drier end of the natural distribution range of Coffea canephora and contains unexplored genetic material that could be drought-adapted and useful for developing climate-resilient varieties. Using water treatment: (i) ample and (ii) restricted-water, the response of 148 genotypes were studied comprising wild, feral and cultivated C. canephora. Biomass allocation, standing leaf area and leaf area growth data were collected. Linear mixed effect models and PCA were used to the analyze effect of water treatment on genotypes from different: (i) cultivation status , (ii) genetic groups and (iii) locations. We also assessed the relationship between drought tolerance for relative growth rate in leaf area (RGRA), total number of leaves (TNL), total leaf area (TLA) and total leaf dry weight (TLDW) of genotypes at final harvest. Restricted-water reduced RGRA across genetic groups (3.2-32.5%) and locations (7.1-36.7%) but not cultivation status. For TNL, TLA and TLDW, genotypes that performed well in ample-water performed worse under restricted-water, indicating growth-tolerance trade-off. Drought tolerance in RGRA and TNL were negatively correlated with wetness index suggesting some degree of adaptation to local climate. Findings indicate a growth-tolerance trade-off within this tropical tree species and drought tolerance of Uganda's C. canephora is somewhat associated with local climate.
... In collaboration with France, experiments set up in the semi-desert Cerrado region are geared towards controlling the duration of the drought period using centralpivot irrigation [12]. Currently, Arabica coffee cultivars such as Acauã [13], Siriema [14], Catuai SH3 [15] and IPR 103 [16], in addition to clonal cultivars of Coffea canephora [17], minimize the negative effects of drought. Similarly, researchers from Yemen and, later, East Africa produced arabica coffee cultivars (e.g., SL28 in Kenya) with relatively higher drought tolerance when compared to the original Ethiopian germplasm [18]. ...
... Seeds of the ten coffee progenies described were obtained from open pollination in Experiment 1 during the first harvest (H1) and were planted in 26 L pots until the developmental stage, with five pairs of leaves for studying in Experiment 2. The cultivars Catuaí Vermelho IAC 99, Catuaí Vermelho IAC 144 and the Siriema (genotypes 11, 12 and 13, respectively) in the seedling stage were used as checks. The "Siriema" has adaptive responses to water scarcity [14] and the cultivars from the Catuai group are widely adopted by Brazilian producers. A mixture of soil, sand and cattle manure (3:3:1, v/v/v) was used as the substrate. ...
This study aimed to establish a strategy for drought-tolerant selection in Arabica coffee genotypes in Brazil, combining field trials under natural conditions with controlled growth condition experiments. A group of genotypes was evaluated in the greenhouse using 28 morphological, anatomical, and physiological traits. In addition, the productivity of genotypes was evaluated in the field. Under water deficit in the greenhouse, 13 studied traits showed significant genetic variance. For these traits, the heritability coefficients estimated based on the progeny mean ranged from 65 to 92%. A selection index combined with predicted means was applied at these traits to select four progenies for drought tolerance under greenhouse conditions. Under field conditions, the selection applied to genetic values that favored positive genetic gains in four progenies, indicating the potential use of these cultivars for breeding advanced generations. The selection results of coffee plants under greenhouse conditions matched the selection results in the field in a water-deficit region by 50% based on productivity; thus, two genotypes (H419-3-3-7-16-11 and H516-2-1-1-7-2) were identified that have both the productivity and morpho-anatomical traits that confer greater drought tolerance. Finally, we discussed possible strategies for the development of drought-tolerant cultivars.
... canephoradiversity (Musoli et al. , 2009;Ngugi and Aluka, 2019;Kiwuka, 2020;Kiwuka et al. , 2021) which could be explored to identify functional diversity in regards to drought stress. But to our knowledge, intraspecific comparisons of drought-related traits in C .canephora have been limited to cultivated material e.g. in (DaMatta et al. , 2003;Pinheiro and Var, 2004;Dias et al. , 2007;Silva et al. , 2013;King'oro, 2014;Menezes-Silvaet al. , 2015). While the aforementioned studies give important insights into the morphological and physiological drivers of drought tolerance, exploration of the variation in drought tolerance across wild populations and potential correlations with climate need to be done. ...
... In our study, T NL and T L were the most affected traits (Table 2) implying that genotypes responded to drought stress mainly by minimising transpirational water loss by reducing the number of leaves and leaf area. Differential reduction in leaf area as a response to drought stress has also been observed by other authors (DaMatta et al. , 2003;Pinheiro et al. , 2004;Dias et al. , 2007;King'oro, 2014). Our current findings extend these observations to a wider range of genotypes including wild, feral and cultivated material. ...
Uganda lies within the drier end of the natural distribution range of Coffea canephora and contains unexplored genetic material that could be drought-adapted and useful for developing climate-resilient varieties. Using experimental treatments, (i) ample and (ii) restricted-water, response of 148 genotypes were studied comprising wild, feral and cultivated C. canephora. Biomass allocation, standing leaf area and leaf area growth data were collected. Linear mixed effect models and PCA were used to analyse effect of drought on genotypes from different: (i) cultivation status, (ii) genetic groups and (iii) locations. We assessed the relationship between drought tolerance for relative growth rate in leaf area (RGRA), total number of leaves (TNL), total leaf area (TL) and total leaf dry weight (TLDW) of genotypes at final harvest. Restricted-water reduced RGRA across genetic groups (3.2 – 32.5%) and locations (7.1 – 36.7%) but not cultivation status. For TNL, TL and TLDW, genotypes that performed well in ample-water performed worse under restricted-water, indicating growth-tolerance trade-off. Drought tolerance in RGRA and TNL were negatively correlated with wetness index suggesting some degree of adaptation to local climate. Findings indicate a growth-tolerance trade-off within this tropical tree species and drought tolerance of Uganda’s C. canephora is somewhat associated with local climate.
... The coffee plant plays a basic part in the social and financial life of the country's population (Bickford, 2019;Minten et al., 2014). On an annual basis, it contributes one-third of the country's export earnings (Amamo, 2014;Diro et al., 2019) and, from the field to cup coffee processing, the coffee agribusiness employs over 15 million people in Ethiopia (Dias et al., 2007;Diro et al., 2019;Minten et al., 2014). ...
... The present coffee-growing locations will become less appealing as the temperature rises (Jaramillo et al., 2011) due to the transformation of their habitats of origin. Extreme temperatures, such as lower and higher temperatures, inhibit the development and growth of the coffee plant by interfering with cellular metabolic processes (Dias et al., 2007;Silva & Mazzafera, 2008). It affects the plant's physiological and phonological processes through reducing CO 2 sequestration and then, reducing photosynthesis (Gray & Brady, 2016;Ramalho et al., 2014). ...
Climate suitability is important for coffee (Coffea arabica L.) production in climate variability-prone regions like Ethiopia. The aim of this study was to assess the current and future climate suitability for the species in the Jimma zone under moderate (RCP4.5) and worst (RCP8.5) climate change scenarios. Field surveys and Worldclim and Paleoclim databases were used to capture 224 C. arabica species’ location points and 9 bioclimatic data, respectively. The MaxEnt model with integration of ArcGis was used to simulate and characterize these data. The diagnostic outcome of the model showed that the anticipated climate change will increase the areas of suitability in the first and third coffee sub-zones, while there will be a decrease in the second sub-zone. Net suitability under the RCP4.5 would be decreased by 4.75 and 6.09% in the 2050s and 2070s, respectively. Indeed, under the RCP8.5, total suitability will be expected to be increased by 2.52% and 2.25% in the 2050s and 2070s, respectively. For the 2050s and 2070s, the suitability gap between RCP4.5 and RCP8.5 was estimated to be 401 km² and 1567 km², respectively. To summarize, with the exemption of RCP 8.5 within the 2070s, the suitability would be improved and come up short in all circumstances. To keep Arabica coffee in its original habitat, we suggest that the entire climate change adjustment procedures that are prearranged under the RCP4.5 ought to be executed to sustain the crop trees in its origin. Otherwise, moving the crop plant from impeded areas to suitable ones is crucial.
... Grafting has been used for a long time to increase the uniformity, vigor and resistance to biotic and abiotic stresses of vegetatively propagated plants (Lee & Oda 2003;Rivero et al. 2003). Genotypes of Arabica coffee have been found to differ in drought adaptation mechanisms, such as stomata control and soil water extraction efficiency (DaMatta & Ramalho 2006), plant water use, and biomass allocation to the stems and leaves (Dias et al. 2007). On the other hand, Robusta coffee showed a deeper root system (Pinheiro et al. 2005) and larger root dry mass in drought-tolerant clones, than in drought-sensitive ones (DaMatta & Ramalho 2006). ...
... After re-watering, 88.33% of the grafted coffee plants were recovered on the third day; however, only 43.33% recovered plants were observed in the non-grafted coffee plants. On the fifth day after rewatering, 100% recovered plants were recovered in the grafted coffee plants; however, only 86.66% recovered plants were observed in the non-grafted coffee plants (Table 4) As a plant adjusts to water stress condition, the biomass allocation between the roots, stems, and leaves of the plant could change (Dias et al. 2007;Worku & Astatkie 2010). Decrease in growth parameters, such as shoots and leaf area under soil moisture deficit are believed to be among the important stress avoidance and tolerance mechanisms in plants (Tesfaye et al. 2014). ...
The objective of this study was to evaluate grafting method to improve the drought tolerance of Coffea arabica. Using C. arabica species as scions, and C. robusta as rootstock, the grafted plant was compared with the non-grafted plant (C. arabica) under water deficit condition. The result shown that growth parameters such as plant height, leaf length, and leaf width of the grafted coffee plants were higher than those of the non-grafted. The leaf area, fresh and dry weight of plants were highly reduced in non-grafted coffee plants. The leaf chlorophyll content (SPAD) and chlorophyll fluorescence (Fv/Fm) values of the grafted and non-grafted coffee plants decreased significantly with increasing duration under water deficit condition. The SPAD and Fv/Fm values of the two coffee types were also increased significantly with increasing duration after re-watering. Compared to the non-grafted plants, higher values of SPAD, Fv/Fm and relative water content in the leaf were observed in the grafted coffee plants. Moreover, lower values of relative ion leakage were observed in the grafted coffee plants after three days of water withholding and one month after re-watering. On the other hand, the grafted coffee plants showed enhanced drought tolerance by reducing the percentages of wilting plant under water deficit condition, and increasing the recovery percentages after re-watering.
... The higher specific root length of Typica compared to CR95 was probably related to the greater increases in leaf area observed for this variety (i.e., increases in evaporative surface were matched by increases in root uptake capacity; Dias et al., 2007). Specific root length is inversely proportional to root tissue density and root diameter squared (Ostonen et al., 2007). ...
Traditional Arabica coffee plantations in which coffee is grown under diverse shade tree cover are increasingly recognized as a sustainable agricultural practice because of their ecological and socioeconomic benefits as well as their resilience to climate change. In addition, organic coffee production has expanded in the last decades due to premium market prices. However, the extent to which coffee and shade trees show positive (complementary) or negative (competitive) root interactions for belowground water sources in traditional agroforests under organic management is largely unknown. The present study investigated relative and absolute source contributions to water uptake of coffee and shade trees under progressive decline of soil water availability during the dry season in an organic coffee plantation characterized by dense and diverse canopy shade. We used the MixSIAR Bayesian stable isotope mixing model to determine proportional use of belowground water sources for three Arabica coffee varieties/ages and five dominant shade tree species. Corresponding absolute uptake amounts by the whole coffee crop and the whole shade tree canopy were calculated using transpiration estimates obtained from microme-teorological and stomatal conductance measurements. The absence or potential presence of competition for soil water in the studied coffee plants was investigated using a combination of stomatal conductance measurements and modeling, supported by leaf and root hydraulic trait data. Results show that the observed relative and absolute plant water uptake patterns provide evidence of vertical complementarity in belowground water use between coffee and shade trees during the dry season. Findings show that the main water source for coffee was the near-surface soil (< 5 cm depth; 44-56 %), with no distinction among coffee varieties and ages. Our data suggest that dew was an important water input to the near-surface soil and to the coffee water cycle. Soil water limitation during the driest period of the study was observed in the youngest coffee plants (5-20 years old), but not in the oldest (~80 years old). Deeper soil water (60-120 cm; 45-69 %) was the main source for the shade trees, but important differences were observed among species, showing the potential of minimizing competition for water through tree species selection. Finally, our study shows that water uptake from groundwater sources increased with increasing tree size.
... This confirmed a relative reduction in stomatal conductance and CO2 assimilation which ensure a higher efficiency of available water by cocoa during water deficit. According to Dias et al. [29] plant physiological responses to soil water availability shows that clones that combine good growth ability with high WUE during dry season would be of great advantages for use in the drought-prone areas. ...
Eleven cocoa clones namely AMAZ 15, ICS 95, IMC 47, MAN 15, PA 150, SCA 9, SPEC 54, UF 67, F3 AMAZON, N 38 and TC 2were hand pollinated and the seeds were raised for 6 months before being transplanted to the field at 6 months. Survival count of the clones was taken for 36 months starting from the first month of establishment. Data on the gas exchange characteristics of cocoa clones started when cocoa were 12 months and continued for the next 2 wet and 2 dry seasons. Majority of cocoa clones showed higher values of stomatal conductance, stomatal transpiration, photosynthetic rates, relative water content, cuticular transpiration and stomata density during wet season while eight of the eleven cocoa clones had higher water use efficiency performance in dry season. The regression analysis also showed a linear, positive and significant relationship between stomatal transpiration and stomatal density of all cocoa clones. The results showed significant differences in the abilities of cocoa clones to cope with water stress while majority of cocoa clones performances significantly differed between dry and wet seasons.
... Physiological evaluations of some of the coffee clones perceived to be drought tolerant suggested that keeping an ade-quate water status, maintenance of leaf area [5,17] and steep leaf inclinations are of utmost importance. Drought-tolerant coffee genotypes are able to maintain higher tissue water potential and water use efficiency than drought-sensitive ones under water-deficit conditions [7]. Such differences are even more evident in the field, where the development of the root system is much less restricted. ...
The growth and output of coffee are significantly hampered by drought. To lessen the effects of climate change on coffee production, it is crucial to choose genotypes of Arabica coffee that are resistant to drought. The goal of the study was to select genotypes of Wellega coffee that are drought-tolerant at the Haru Agricultural Research Sub-Center in the Oromia National Regional State, Western Ethiopia. The experiment was carried out in a controlled environment from 2017 to 2019 G. C., with three replications laid out in RCBD. For 28 days, two watering regimes—well-watered and water-stressed—were applied to fourteen genotypes of Wellega coffee. The mother trees of genotype were tested at field condition. The experiment's findings showed that the genotypes not differed significantly in terms of total dry matter, relative leaf water content, and leaf retention capacity as well as in terms of the degree of wilting and in all destructive parameters. So, to select the drought tolerance coffee genotypes the stress period should be minimized in to 15-21 days.
... physiological modifications were observed in C. arabica (Vu et al., 2018). Therefore, irrigation is highly recommended for great part of coffee areas in Brazil, as rainfed conditions negatively impact plant growth traits, such are relative growth rate or leaf area (Dias et al., 2007;Souza et al., 2016), but no differences are observed in the number of leaves or number of 2 nd order branches due to irrigation (Chemura, 2014). C. arabica genotypes show reduction in physiological and productive traits when cultivated under rainfed compared to irrigated conditions in Brazilian Cerrado, a very dry environment, with Iapar 59 cultivar highlighted as the most productive and a wild Ethiopia accession 'E237' as the less productive one (Silva et al., 2022). ...
In Coffea arabica, there is a small genetic distance between wild and bred genotypes. However, coffee
genotypes express differential acclimation to multiple drought cycles, allowing them to successfully deal
with water-limiting conditions. We hypothesized that bred coffee cultivars have a plant structure less
sensitive to drought than wild genotypes. Plant and leaf architecture were analyzed over the coffee strata of
two cultivars (Iapar 59 and Catuaí 99) and two wild Ethiopia accessions (‘E083’ and ‘E027’) grown under
rainfed conditions and irrigation. During two consecutive productive years, evaluations were taken at leaf
and berry expansion (BE1 and BE2) and harvest (BH1 and BH2) phenophases. The plant canopy was
divided into up to four strata of 40 cm of thickness. Topological and geometric coding of coffee trees was
performed in three botanical scales – metamers, branches, and plants in multiscale tree graphs (MTGs),
following the VPlants modeling platform. Leaf and branch area per plant increased with tree structure
development, being always significantly higher in irrigated than in rainfed plants over all phenophases. The
individual leaf area was the least sensitive to water regime in Catuaí 99, while the 2nd order axis elevation –
angle in relation to horizontal plane, ranging from 0° to 90° – of bred cultivars was less sensitive to drought
than in ‘E083’. This finding partially corroborated our hypothesis that orchestrated reprograming of leaf/
branch responses over the vertical plant profile were less sensitive to water availability in cultivars than in
wild accessions. Leaves of 2nd to 4th-order branching were roughly plagiophile, while the 1st-order leaves
were classified as extremophiles. When the coffee leaves were planophile, irrespective of genotype, this
pattern was found at the lowest, 1st plant stratum, and the newest developed 4th stratum. Such responses
were not obligatorily related to water regime, similar to branch elevation – with exception of ‘E083’, very
sensitive to drought. Taken together, our data suggest that the leaf and branch elevations in C. arabica were
more influenced by light distribution through the canopy profile – i.e., self-shading – than by water
availability.
... In West Africa, climate change and drought consistently impact livelihoods (Gautier et al., 2016). Furthermore, drought serves as a significant environmental factor influencing coffee growth and production (Dias et al., 2007). In addition to the impacts of climate change, political stability also affects the implementation of agricultural and sustainable development goals. ...
Climate change has directly impacted coffee‐producing regions in Africa. This study uses the two stage Dynamic Network Directional Distance Function (DN‐DDF) and Malmquist Productivity Index (MPI) methods to evaluate the efficiency and productivity changes of agricultural production and sustainable development in 19 African coffee‐producing countries from 2014 to 2018. According to the empirical results, Central African Republic, Ethiopia, Liberia, Uganda, and Zambia have the highest overall efficiency. This study has three main contributions: (1) using a two‐stage model to evaluate the impact of agricultural production efficiency on sustainable development efficiency, (2) using a dynamic model with forest area as a cross‐period variable to reflect the real‐world phenomenon of coffee relying on forest mixed planting, and (3) objectively evaluating the impact of extreme weather on agricultural production by using rainfall as an exogenous variable to address previous research shortcomings. The results of this study can promote the improvement of agricultural production efficiency in African coffee‐producing countries and provide important reference value for sustainable development goals.
... Some crops show postpone drought tolerance mechanism by having deep root growth in the soil; likewise, DaMatta [5] and Blum [46] reported that plants characterized with deep and vigorous root systems are drought tolerant. Due to their deep root trait, the 120 robusta clones showed drought tolerance with minimum leaf area decreasing per tree; but, for 46 clones having shallow root, drought sensitivity was observed under moisture deficit [4,47]. Similarly, finding elucidated that root length, root thickness and root volume were positively correlated with leaf water potential under water deficit [48]. ...
... La tasa de transpiración de plantas enteras fue estimada gravimétricamente (Dias et al., 2007), y calculada usándose los datos de la duración de la transpiración (h), área foliar total (AFT) y variaciones de peso de las macetas, entre antes de la mañana (P1) y el medio día (P2): ...
La tolerancia a la inundación del suelo en algunas plantas leñosas ha sido asociada a la manutención de la conductancia hidráulica de la planta. Para evaluar la existencia de una relación de esta variable con la tolerancia a la inundación del suelo en plantas de dos clones (120 e 109A) de Coffea canephora (caracterizados, respectivamente, como tolerante y sensible a sequía) fueron realizadas mediciones de potencial hídrico foliar, transpiración y conductancia hidráulica de la planta. Los clones fueron sometidos a dos tratamientos de irrigación (control e inundación), por seis días, seguidos de 40 días de reoxigenación (recuperación). La inundación ocasionó disminuciones de potencial hídrico de medio día, transpiración y de absorción de agua radicular, con pérdida de 70% en la conductancia hidráulica en ambos clones. A pesar de que el clone 120 mostró menor afectación por déficit hídrico, se concluye que el C. canephora es sensible a los efectos de la inundación del suelo.
... In view of the above, Dias et al. (2007), found that when the vegetative growth of coffee was not reduced in relation to monoculture, there was possibly no competition, due to the high potential for extracting water and nutrients from the soil, that is, the existence of dynamic interactions between the species. According to Godoy et al. (2017), when there is competition between plants for light, it favors plant growth in height in comparison to monoculture. ...
The insertion of the tree component in coffee production is a strategy from an economic and environmental perspective. Thus, the objective of this study was to evaluate the temporal influence on the agronomic and productive performance of the coffee crop under the interference of different tree species as a function of spacing. The experiment was set in the municipality of Santo Antônio de Amparo-MG, in 2012, and conducted in a randomized block design with four replications. The treatments were: cultivar ‘Catuai Vermelho IAC 99’ in monoculture (3.40 m x 0.65 m) and intercropped with African mahogany, teak and pink cedar, in two spacings (9 x 13.6 m and 18 x 13.6 m), in coffee rows. Three coffee rows were fixed between rows, totaling 13.6 m. The following variables were evaluated: height (m), stem diameter (cm), crown diameter (m), productivity (bags ha⁻¹) and yield (l/sc) for coffee. From the evaluations, there is a significant effect of height, productivity and yield for the coffee crop. The system intercropped with tree species did not influence coffee productivity and yield until the 3rd harvest and, for the 5th harvest, intercropping with mahogany favored productivity, although the accumulated productivity did not show any treatment effect.
Keywords
Acrocarpus fraxinifolius ; Coffea arabica ; Khayana ivorensis ; Tectona grandis ; agroforestry system
... Within a certain range, the content of glycyrrhizin in licorice is positively correlated with soil water 20,21 . Drought stress reduces plant photosynthesis and affects plant growth [22][23][24] . In potted licorice plants, the content of glycyrrhizic acid is lowest when the soil moisture is 12% and decreases when it is higher than 14% 25 . ...
Wild licorice in China is mainly distributed in northern China, such as Gansu, Ningxia, and Inner Mongolia Provinces. The origin of wild licorice has varied among historical periods. The cultivated origin of planted licorice has the same as 59.26% of wild licorice. The distribution of cultivated licorice was shifted to the northwest relative to that of wild licorice. The yield and quality of cultivated licorice vary greatly from different origins, showing a certain pattern of variation from west to east. The same batch of licorice seedlings was planted at 8 sites overlapping the main licorice production areas in China. The yield and quality of licorice in the Baicheng experimental plot were low. The yield of licorice in the Jingtai and Altay experimental plots was high, but the quality was poor. The quality of licorice in Chifeng and Yuzhong experimental sites was high, but the yield was low. Principal component analysis of environmental and soil factors generated five characteristic roots with a cumulative contribution rate of 80%, three of which were related to soil and referred to as the soil charge factor, soil water factor, and soil nutrient factor, and the load coefficients of the water and nutrient factor were the largest. Soil conditions, especially water and nutrients, might have a substantial effect on the observed changes in the licorice production area. Generally, the regulation of water and nutrients merits special attention when selecting areas for the production and cultivation of licorice. This study can provide reference for the selection of cultivated licorice production areas and the research of high-quality cultivation techniques.
... Moreover, additional adverse effects on coffee plants included a reduction in net photosynthesis, transpiration rate, net carbon assimilation rate, and an increase in long-term water-use efficiency (WUE). These effects may lead to crop yield losses and modifications in the quality and postharvest preservation of coffee products, as well as the risk of pest and disease attacks [81][82][83][84][85]. In addition, significant alterations may occur in the expression of genes associated with abiotic stress and senescence. ...
Coffee production is fragile, and the Intergovernmental Panel on Climate Change (IPCC) reports indicate that climate change (CC) will reduce worldwide yields on average and decrease coffee-suitable land by 2050. This article adopted the systematic review approach to provide an update of the literature available on the impacts of climate change on coffee production and other ecosystem services following the framework proposed by the Millenium Ecosystem Assessment. The review identified 148 records from literature considering the effects of climate change and climate variability on coffee production, covering countries mostly from three continents (America, Africa, and Asia). The current literature evaluates and analyses various climate change impacts on single services using qualitative and quantitative methodologies. Impacts have been classified and described according to different impact groups. However, available research products lacked important analytical functions on the precise relationships between the potential risks of CC on coffee farming systems and associated ecosystem services. Consequently, the manuscript recommends further work on ecosystem services and their interrelation to assess the impacts of climate change on coffee following the ecosystem services framework.
... The genotypes 1, 2, 8, 9, 10, 11 and 12 originate from the Paraíso group; 4, 5 and 6 from the Araponga group; and 7 from the Pau-Brasil group. The "Siriema" has adaptive responses to water scarcity (Dias et al. 2007) and the cultivars from the Catuaí group are widely adopted by Brazilian producers. ...
The development of more drought-tolerant cultivars is essential for the maintenance of global agricultural production. This study aimed to perform an early selection of drought-tolerant Coffea arabica genotypes by evaluating their functional divergence using morphological, anatomical and physiological analyses. Seedlings of 14 genotypes were subjected to the drought stress imposed by irrigation for 18 days. Growth and anatomical parameters, leaf water potential and gas exchanges were measured. Under irrigated conditions and prolonged drought (18 days), the divergence among the genotypes was determined mainly by morphological traits, such as leaf area, stem diameter and, consequently, shoot dry mass. Under moderate drought (14 days), parameters such as water potential, cuticle thickness, stomatal density, number of xylem vessels and water-use efficiency were important for the divergence of the group with the highest ability to maintain its water status. The genotypes 1, 2, 4, 11 and 12 have characteristics that contributed to the maintenance of water status, such as greater cuticle thickness, stomatal density, smaller number of xylem vessels and phloem thickness, bigger root length and greater water-use efficiency. The functional divergence combining morphological, anatomical and physiological analyses in response to the moderate drought indicated the early selection of the genotypes 1, 2,4, 11 and 12 as more drought tolerant during the seedling stage.
KEYWORDS:
Coffee; water-use efficiency; leaf water potential
... This could be due to their ability to maintain water potential through moderate water use rates, similar to drought-tolerant C. canephora clones that have higher WUE and better control of water loss due to transpiration attributable to stomatal closure (DaMatta et al., 2003). As a result, dehydration is postponed without reducing leaf area, photosynthesis, and total biomass values because of the activation of the ABA and nitric oxide signaling pathways (Dias et al., 2007;Marraccini et al., 2012;Silva et al., 2013). In contrast, variety Caturra (susceptible to water deficit) reduced its total biomass in water deficit conditions as compared with the irrigation at field capacity. ...
Approximately 26% of the coffee grown in Colombia is located in areas presenting water deficit, with some of these areas also presenting high solar brightness. This combination reduces coffee production, thus affecting the income of 31% of the country’s coffee-growing families. To identify accessions of the Colombian Coffee Collection (CCC) that are tolerant to water deficit, 65 genotypes were evaluated in screenhouse conditions using two soil moisture treatments: (1) soil at field capacity (60% moisture) and (2) water deficit conditions, with soil at 50% field capacity (30% moisture). After five months, total biomass was determined as the sum of the biomass of leaves, stems, and roots, and values analyzed according to the Student's t test for independent samples at a level of significance of 5%. Reducing irrigation under water deficit conditions usually delays accession growth, which is reflected in decreased biomass. However, the total biomass of nine Ethiopian introductions of Coffea arabica (CCC238, CCC254, CCC284, CCC372, CCC474, CCC536, CCC537, CCC555, CCC1147), six diploid accessions (CCC1030, EA.20, EA.209, EA.227, EA.229, EA.287), and three interspecific hybrids of Caturra x Coffea canephora (25, 640, 702) in water deficit conditions did not differ statistically from the total biomass obtained in treatments with irrigation at field capacity. Because these introductions present adaptation mechanisms to water deficit, they retain their leaves without reducing their leaf area or total biomass and should accordingly be considered as candidates for evaluation in dry regions to determine their tolerance to water deficit based on effects on production or biomass. Key words: Coffea arabica; Coffea canephora; interspecific hybrids; total dry biomass; water stress.
... It is estimated that nearly 50% of reduction in agricultural production is due to drought and other abiotic stresses [1,2]. Long period and high intensity of drought stress not only delays the growth of plants, but also results in changes of the morphological structure and the physiological processes, or even death [3,4]. In order to resist drought stress, plants maintain basic life activities through specific cellular and molecular activities, including the expression of drought-tolerant genes and the accumulation of drought-related proteins [5][6][7]. ...
Miscanthus lutarioriparius is a species of bioenergy crop unique to China. It is widely distributed in the south of China with high resistance to drought and salt stress. To date, the molecular mechanism of the adaption to drought stress in M. lutarioriparius is little known. In this study, RNA-seq technology was employed to analyze the transcriptome changes of diploid and tetraploid M. lutarioriparius after drought treatment. It was found that the number of differentially expressed genes in diploid M. lutarioriparius was much higher than tetraploid, whereas the tetraploid M. lutarioriparius may require fewer transcriptional changes. While the transcriptional changes in drought-tolerant tetraploid M. lutarioriparius are less than that of diploid, more known drought-tolerant pathways were significantly enriched than drought-sensitive diploid M. lutarioriparius. In addition, many drought-tolerance-related genes were constitutively and highly expressed in tetraploid under either normal condition or drought stress. These results together demonstrated that drought-tolerant tetraploid M. lutarioriparius, on the one hand, may preadapt to drought by constitutively overexpressing a series of drought-tolerant genes and, on the other hand, may adapt to drought by actively inducing other drought-tolerant-related pathways. Overall, this study could deepen our understanding of the molecular mechanism of drought-tolerance in bioenergy plants.
... Nevertheless, both inadequate temperatures and water availability conditions are the main environmental constraints to plant development and production [27]. However, some cultivars show a significant resilience under drought, extreme temperatures, and full sunlight, triggering a wide number of energy dissipation and antioxidant mechanisms [19,[30][31][32][33] as well as by changing the lipid matrix of their chloroplast membranes [34][35][36]. For instance, genotypes of both C. arabica and C. canephora can display different drought tolerance levels, although in general, C. canephora is thought to be more tolerant than C. arabica to prolonged periods of drought, as empirically observed in coffee plantations [28]. ...
Drought is a major threat to coffee, compromising the quality and quantity of its production.
We have analyzed the core proteome of 18 Coffea canephora cv. Conilon Clone 153 and C. arabica cv. Icatu plants and assessed their responses to moderate (MWD) and severe (SWD) water deficits. Label-free quantitative shotgun proteomics identified 3000 proteins in both genotypes, but less than 0.8% contributed to ca. 20% of proteome biomass. Proteomic changes were dependent on the severity of drought, being stronger under SWD and with an enrolment of different proteins, functions, and pathways than under MWD. The two genotypes displayed stress-responsive proteins under SWD, but only C. arabica showed a higher abundance of proteins involved in antioxidant detoxification activities. Overall, the impact of MWD was minor in the two genotypes, contrary to previous studies. In contrast, an extensive proteomic response was found under SWD, with C. arabica having a greater potential for acclimation/resilience than C. canephora. This is likely supported by a wider
antioxidative response and an ability to repair photosynthetic structures, being crucial to develop new elite genotypes that assure coffee supply under water scarcity levels.
... Kondisi fisik dan hidrologis tanah yang memadai merupakan kondisi kunci untuk pengembangan tanaman kopi secara penuh, yang merupakan premis untuk kualitas kopi karena persyaratan kualitas buah dan biji kopi dan keseragaman tanaman kopi. Kandungan air dalam zone perakaran tanaman kopi merupakan salah satu faktor utama pertumbuhan dan vigor produktif tanaman kopi, terutama karena kopi umumnya ditanam pada sistem lahan kering tadah hujan(Pinheiro et al., 2005;Dias et al., 2007). Pengetahuan tentang dinamika air tanah di zona perakaran tanaman kopi sangat strategis karena dapat memprediksi keberhasilan kebun kopi. ...
Water is one of the limiting factors in the growth of coffee plants. If plants experience a lack of water, it can inhibit plant growth and, at a critical level, can lead to drought stress and plant damages. The available soil water to plants can be estimated from the level of soil moisture index. The monitoring of soil moisture status can be used in improving the management of coffee plantations. Soil Moisture Index (SMI) is a method that can be used to estimate the level of soil moisture using remote sensing technology using NDVI and LST values. The purpose of this study was to analyze the status and distribution of soil moisture at the coffee plantation; analyze the relationship between vegetation index and soil moisture; and analyzed the relationship between soil moisture status using the SMI method and soil moisture measured in coffee plantations. Results showed that the soil moisture index obtained from Landsat 8 OLI/TIRS image processing had an average value of 0.60. The average soil moisture index at the study site is 1.05. Soil moisture index from the Landsat 8 OLI/TIRS image has a significant positive effect on soil moisture at the study site (y = 7.4996x – 3.4789; R2 = 0.7146**). It is suggested that the SMI method can be used to estimate soil moisture in the coffee plantation.
... Relationship between shoot and root growth is altered during water deficit condition. D water deficit condition, the plant spends more energy towards growth of root as it needs to go deeper in search of water and so the growth of roots is high [16]. Shoot growth and plant performance majorly dependent on the root growth for getting water and minerals. ...
In the present global climate change scenario, drought stress is the major threat to agriculture productivity and yield. Water stress leads to physiological, biochemical and molecular changes in the plants. Green gram (Vigna radiata L.) contains 23% protein and is widely used as a protein source in the diet. Seed germination and early seedling stages are more susceptible stages for drought. Pranic agriculture (PA) is an ancient agriculture method where energy as prana is applied to the crop during stress to enhance yield. A pilot study was carried out by imposing stress at seedling stage by withholding water for 6 days and then re-watered and kept for recovery. Pranic treatment was given to the seedlings at the time of stress. Pranic treated seedling showed significantly (p< .001) higher shoot length (20.68 cm), root length (7.87 cm), Root/ Shoot ratio (0.38) leaf area (6.73 cm 2) and seedling fresh weight (0.51 g), when compared with the control (19.06, 5.06, 0.27, 3.15 and 0.40) respectively. Pranic treatment also showed in overcoming stress effect and recovery. Root growth and leaf area reduction were found to be beneficial to combat drought stress and recovery. Pranic treated seedling showed better plant growth, survival and recovery as compared to control seedlings. PA may help to overcome drought and other abiotic stress problems in agriculture. Further field investigations and exact stress management mechanism involved need to be studied.
... At farm scale, these strategies typically include irrigation, water-saving technologies, conservation of soil water through mulching, shade management (e.g. shading systems with tree species, agroforestry, etc.), and diversification of farm activities (DaMatta, 2004a;Dias et al., 2007;Silva et al., 2008;Worku and Astatkie, 2010;Haggar and Schepp, 2012;Jassogne et al., 2013;Assis et al., 2014;Bisang et al., 2016;Boreux et al., 2016). Mulching is a practice consisting of spreading a layer of materials (i.e. ...
An improved understanding of the benefits and uptake of drought mitigation strategies under a changing climate is critical to ensure effective strategies are developed. Here, using 10 years (2008–2017) of farm data from 558 farmers distributed across the major robusta coffee-producing provinces in Vietnam, we analysed coffee farmers’ perceptions on drought and its impacts; we then quantified the impacts of drought on yield and farm profit, and finally, assessed the effectiveness of mitigation strategies. While drought reduced robusta coffee yield by 6.5% on average across all provinces, the impacts on gross margins were noticeable, with an average 22% decline from levels achieved in average-rainfall-condition years. Yield reductions from drought were consistent with farmers’ perceptions, being on average − 9.6%. With irrigation being typical in coffee farming in Vietnam, the majority of surveyed farmers (58%) adopted mulching in drought years and had a 10.2% increase in economic benefits compared to their counterparts who did not. Furthermore, the chances of adopting mulching as an adaptation strategy decreased generally for every one unit increase in perceived drought impact or when shifting from surface water to groundwater in drought years. Although coffee farming remained profitable in drought years, our findings have potential relevance for the design of policies to address drought risks and encourage more resilient adaptation strategies for Vietnam and other coffee-producing countries experiencing similar climatic conditions.
... Although plant traits that increase WUE may conflict with growthpromoting traits, there is potential to improve WUE without necessarily reducing biomass production. 22 As an important indicator of plants' ability to obtain assimilates, biomass plays a vital role in plant morphological construction and organs development. 23 The biomass allocation ratio of plant organs is related to their habitats, and usually adjusted according to the conditions of the habitats, and thus can increase plant tolerance to the drought stress. ...
Differentiate mechanism of wheat species in response to contrasting drought stress gradients implies a cue of its long-term domestication. In the present study, three water regimes including well-watered control (WW, 80% field water capacity (FC)), moderate drought stress (MS, 50% FC,) and severe drought stress (SS, 30% FC) were designed to reveal different responses of eight wheat species (four tetraploid and four hexaploid) representing different breeding decades and genetic origins to drought stresses. The data indicated that 50% FC and 30% FC fell into the soil moisture threshold range of non-hydraulic and hydraulic root signal occurrence, respectively. In general, grain yield, grain number/spike weight per plant, aboveground biomass, harvest index (HI) and water use efficiency (WUE) were significantly higher in hexaploid species than those of tetraploid species under drought stress (P < .05). Particularly, non-hydraulic root signal was triggered and continuously operated under 50% FC, while hydraulic root signal was observed under 30% FC, respectively. Under 80% FC, the allometric exponent (ɑ) of M aboveground vs M root decreased from tetraploid to hexaploid (both were of <1), indicating that during the domestication, the hexaploid species allocated less biomass to root system. For the relationship of M ear vs M vegetative , the ɑ value was significantly greater in the hexaploid species, showing that hexaploid wheat distributed more biomass to ear than tetraploid to improve yield. Under 50% FC, this trend was enhanced. However, under 30% FC, there was no significant difference in the ɑ value between two species. Additionally, correlation analyses on yield formation affirmed the above results. Therefore, drought tolerance tended to be enhanced in hexaploid species under the pressure of artificial selection than that of tetraploid species. When drought stress exceeded a certain threshold, both species would be negatively seriously affected and followed a similar mechanism for better survival. ARTICLE HISTORY
... Coffee plants have a common set of response mechanisms allowing them to cope with single stress events, including high irradiance, drought, cold, and heat (Nunes et al., 1993;Pinheiro et al., 2004;Ramalho et al., 2014b;Martins et al., 2019). Under water shortage, drought-tolerant coffee genotypes reduce g s to avoid excessive transpiration and trigger antioxidant molecules (DaMatta et al., 2003;Pinheiro et al., 2004;Dias et al., 2007). Regarding heat stress, recent studies showed that coffee can maintain photosynthetic performance up to 37°C, well above what was traditionally assumed (DaMatta et al., 2018). ...
This study unveils the single and combined drought and heat impacts on the photosynthetic performance of Coffea arabica cv. Icatu and C. canephora cv. Conilon Clone 153 (CL153). Well-watered (WW) potted plants were gradually submitted to severe water deficit (SWD) along 20 days under adequate temperature (25/20°C, day/night), and thereafter exposed to a gradual temperature rise up to 42/30°C, followed by a 14-day water and temperature recovery. Single drought affected all gas exchanges (including Amax ) and most fluorescence parameters in both genotypes. However, Icatu maintained Fv/Fm and RuBisCO activity, and reinforced electron transport rates, carrier contents, and proton gradient regulation (PGR5) and chloroplast NADH dehydrogenase-like (NDH) complex proteins abundance. This suggested negligible non-stomatal limitations of photosynthesis that were accompanied by a triggering of protective cyclic electron transport (CEF) involving both photosystems (PSs). These findings contrasted with declines in RuBisCO and PSs activities, and cytochromes (b559 , f, b563 ) contents in CL153. Remarkable heat tolerance in potential photosynthetic functioning was detected in WW plants of both genotypes (up to 37/28°C or 39/30°C), likely associated with CEF in Icatu. Yet, at 42/30°C the tolerance limit was exceeded. Reduced Amax and increased Ci values reflected non-stomatal limitations of photosynthesis, agreeing with impairments in energy capture (F0 rise), PSII photochemical efficiency, and RuBisCO and Ru5PK activities. In contrast to PSs activities and electron carrier contents, enzyme activities were highly heat sensitive. Until 37/28°C, stresses interaction was largely absent, and drought played the major role in constraining photosynthesis functioning. Harsher conditions (SWD, 42/30°C) exacerbated impairments to PSs, enzymes, and electron carriers, but uncontrolled energy dissipation was mitigated by photoprotective mechanisms. Most parameters recovered fully between 4 and 14 days after stress relief in both genotypes, although some aftereffects persisted in SWD plants. Icatu was more drought tolerant, with WW and SWD plants usually showing a faster and/or greater recovery than CL153. Heat affected both genotypes mostly at 42/30°C, especially in SWD and Icatu plants. Overall, photochemical components were highly tolerant to heat and to stress interaction in contrast to enzymes that deserve special attention by breeding programs to increase coffee sustainability in climate change scenarios.
... As maize is usually a winter condition and due to low rainfall, the growth of maize and yield of maize are severely affected by drought stress [3]. Under drought stress, plant photosynthesis can significantly decrease, consequently reducing the amount and energy of metabolites [4] required for the proper development of both the aboveand belowground biomass [5]. In severe water shortage conditions, the roots will shrink and in the leaves induced deposition. ...
This chapter discussed on mitigating effects of rice husk biochar to the drought effect on maize ("BARI Hybrid Bhutta 9"). Four doses of rice husk biochar at 0, 5, 10, and 20 t/ha were applied in soil before sowing of seed. Drought treatments were maintained at 60% of field capacity and 40% of field capacity by watering every alternate day, and 80% of field capacity (control) was also maintained as well-watered treatment. Plant growth and physiological parameters were studied at 6th leaf, 10th leaf, 14th leaf, tasseling stage, cob initiation stage, and maturity stage, and yield contributing parameters were studied after harvest. Soil physical and chemical properties were studied before sowing and after harvest of crop. Drought stress reduced plant morphological growth and affected physiology and yield of maize. Mitigation of drought stress in maize was well associated with the reduction of proline content, maintenance of water-related traits, exudation rate and enhanced chlorophyll content and SPAD value, as well as dry matter production. Rice husk biochar improved the growth and yield performance of maize under drought condition. Biochar application at 20 t/ha was the best treatment to improving drought tolerance in maize.
... Long-term WUE is an important trait associated with yield and adaptation to water deficit (Monti et al., 2006;Rajabi et al., 2008). The ability to recognize genotypes that combine high yield with high WUE is essential when breeding crops for drought-prone areas (Acosta-Rangel et al., 2018;Dias et al., 2007;dos Santos et al., 2016). Although the importance of screening large numbers of crops under similar agricultural management has been recognized, many breeding programs fail due to inappropriate clone choice for a certain region as a consequence of inadequate knowledge of the potential of clones and their growth and productivity under different site conditions (Rajabi et al., 2008). ...
In order to assess the response of cocoa trees to drought, changes in water status, gas exchange, leaf carbon isotopic ratio ( δ¹³ C), photochemical activity, and leaf N and chlorophyll content during the rainy and dry season were measured in 31 Venezuelan cocoa clones (17 Trinitarios, 6 Criollos, and 8 Modern Criollos) grown in a common garden. Drought caused a 40% decrease in water potential ( ψ ) in all but the Modern Criollos, and a reduction in net photosynthetic rate ( A ) and stomatal conductance ( gs ) without an increase in instantaneous water use efficiency (WUE) in 93% of clones, and an increase in δ¹³ C (long-term WUE) in 74% of clones; these responses suggest differences in tolerance to drought among clones. A positive correlation between A and both gs and leaf N content was found for all genotypes. Leaf N content, chlorophyll content, and photochemical activity were reduced during drought, suggesting that metabolism was also inhibited. The best performance during drought was shown by Modern Criollos with the highest WUE, while five Trinitario clones seemed to be less sensitive to drought, since neither chlorophyll, N, total soluble protein concentration, nor gs changed with drought, indicating that those Trinitario clones, with lower A , have a conservative water use. Modern Criollos showed no reductions in either ψ or gs ; A remained unchanged, as did WUE, which was the highest, suggesting that these clones would be more successful in environments with low water availability. Our results indicate large variation in physiological response to drought over a range of parameters, suggesting possible differences in tolerance among clones.
In the context of global climate change, exploring how plant adaptation and responses to drought vary among different regions are crucial to understanding and predicting its geographic distribution. In this study, to explore the drought adaptation and responses of the dominant species in the semi‐arid Eurasian Steppes and their differences among the different regions in terms of growth, physiology, and RNA‐seq transcriptome, Stipa krylovii was chosen as the study material, and a seed source (three regions: eastern, middle, and western regions) × soil moisture treatment (three treatments: control, light drought, and heavy drought) two‐factor experiment was conducted. (1) Four growth traits for individuals from the western region were significantly lower than those from the other two regions. By Kyoto Encyclopedia of Genes and Genomes (KEGG) functional enrichment analysis on gene expressions of individuals from each treatment, unique enriched pathways were found under heavy drought. (2) The decrease in the number of tillers with the increasing drought was much lower for individuals from the western region than those from the other two regions. The differentially expressed genes (DEGs) of individuals from the eastern, middle, and western regions between heavy drought versus control were 4887, 1900, and 4896. By KEGG functional enrichment analysis, individuals from the eastern and middle regions mainly regulated energy metabolism and metabolism of other amino acids; and those from the western region mainly regulated biosynthesis of other secondary metabolites and carbohydrate metabolism. (3) Clustering analysis based on gene expressions separated the western region from the other two regions under the same drought treatment. This study indicates that drought adaptation and responses of S. krylovii vary among different regions, especially between individuals from the western region and the other two regions. These findings are essential to understanding the adaptive evolution of population and germplasm resource protection for this important species.
Ethiopian coffee production is greatly hampered by frequent droughts.This study aimed to evaluate the performance of a drip irrigation system for coffee production on a farm. Additionally, it estimated the amount of water required for coffee crops. An experiment was conducted on a 5-year-old coffee plant with 2m spacing between lines and 2m between plants. Catch cans were used to evaluate the system performance of the installed drip irrigation system. Based on these, the average hydraulic characteristics of the installed drip irrigation system, distribution uniformity was 93.55%, Christiansen uniformity coefficient was 95.40%, flow variation was 18.52%, and coefficient of variation was 5.59%. Coffee plants grew and produced more when irrigation was used. A fresh cherry yield of 6785 kg ha-1 was obtained under irrigated coffee and 2346 kg ha-1 under non-irrigated coffee. Compared to non-irrigated coffee, irrigated coffee had the highest crop water use efficiency of 2.5 kg ha-1 mm-1, and the lowest was obtained 1.7 kg ha-1 mm-1, under non-irrigated coffee. Similarly, irrigated coffee had the highest irrigation water use efficiency (3.6 kg m-3), whereas non-irrigated coffee had the lowest (1.4 kg m-3). These findings show that drip irrigation, compared to non-irrigated coffee plants, enhances yield and water use efficiency by 65% and 60%, respectively. In order to boost production, yield, yield components, and irrigation water use efficiency, drip irrigation is a helpful irrigation technique in locations with limited water resources and extended drought spells. Int. J. Agril. Res. Innov. Tech. 13(1): 42-47, June 2023
Dry land with low fertility causes low productivity. Ameliorant of rice husk charcoal (RHC) has potential to improve soil properties and increasing rice productivity. This study investigates the RHC effect on soil properties, rice growth and yield in the dry land. The experimental research was held in Gunungkidul, with randomized complete block design consists of 6 treatments and 3 replications. The treatment was dose of RHC, consisting of without RHC (Control), RHC at dose of 1 ton ha ⁻¹ (RHC1), 2 ton ha ⁻¹ (RHC2), 3 ton ha ⁻¹ (RHC3), 4 ton ha ⁻¹ (RHC4), and 5 ton ha ⁻¹ (RHC5). The results showed that giving RHC increased soil pH to 6.43 and decreased soil Eh to 54 mV. RHC at a dose of 3 ton ha ⁻¹ (RHC3) was chosen as alternative, producing dry grain by 4.94 ton ha ⁻¹ , dry straw by 6.31 ton ha ⁻¹ , carbon absorption in grain by 2.65 ton ha ⁻¹ and straw by 2.92 ton ha ⁻¹ , and reduces the percentage of empty grain up to 5.38%. Ameliorant of RHC improves soil properties, better growth, increasing rice productivity, better grain quality, and maintains environmental quality through carbon absorption.
Increased evidence has shown that hydrogen sulfide (H2S), a novel gasotransmitter, could enhance drought resistance in plants by inducing stomatal closure, with concurrent enhancement of photosynthetic efficiency, but little is known about the mechanism behind this contradictory phenomenon. This study examined the regulating mechanism of H2S in response to drought stress from stomatal and non-stomatal factors in Chinese cabbage. The results showed that exogenous H2S could increase the accumulation of photosynthetic pigments and alleviate the damage caused by drought stress. It also regulated the expression in transcriptional level and the activity of ribulose 1,5-bisphosphate carboxylase/oxygenase (BrRuBisCO) under drought stress. The large subunit of BrRuBisCO was found to be modified by S-sulfhydration, which might be the reason for its increased enzyme activity. The fluxes of Cl−, K+, and H+ in the guard cells were detected by non-invasive micro-test techniques while under drought stress. The results indicated that H2S signaling induced a transmembrane Cl− and H+ efflux and inhibited K+ influx, and the Cl− channel was the main responders for H2S-regulated stomatal movement. In conclusion, H2S signal not only activated the ion channel proteins located in the guard cell membrane to induce stomatal closure, but also regulated the transcriptional expression and the activity of RuBisCO, a non-stomatal factor to enhance the photosynthetic efficiency of leaves. There is therefore a beneficial balance between the regulation of H2S signaling on stomatal factors and non-stomatal factors due to drought stress, which needs to be better understood to apply it practically to increase crop yields.
Wild licorice in China is mainly distributed in northern China, such as Gansu, Ningxia, and Inner Mongolia Provinces. The origin of wild licorice has varied among historical periods. The origin of cultivated licorice in 59.26% of the cities that possess it was the same as that of wild licorice. The distribution of cultivated licorice was shifted to the northwest relative to that of wild licorice. Substantial variation was observed in the yield and quality of cultivated licorice in different production areas in China, and geographic variation was observed from west to east. The same batch of licorice seedlings was planted at 8 sites overlapping the main licorice production areas in China. The yield and quality of licorice in Baicheng experimental plot were low. The yield of licorice in the Jingtai and Altay experimental plots was high, but the quality was poor. The quality of licorice in Chifeng and Yuzhong experimental sites was high, but the yield was low. The HPLC fingerprint similarity of licorice samples from Baicheng, Jilin, and Suide, Shaanxi was low. Principal component analysis of environmental and soil factors generated five characteristic roots with a cumulative contribution rate of 80%, three of which were related to soil and referred to as the soil charge factor, soil water factor, and soil nutrient factor. The load coefficients of the water and nutrient factor were the largest, indicating that soil conditions had a substantial effect on the yield and quality of cultivated licorice. Soil conditions, especially water and nutrients, might have a substantial effect on the observed changes in the licorice production area. Generally, the regulation of water and nutrients merits special attention when selecting areas for the production and cultivation of licorice.
Coffee is the most frequently consumed functional beverage world wide. The average daily coffee consumption is increasing. This crop, which plays an important role in the global economy is under great threat from climate change. To with stand the current climate change, farmers have to learn crop cultivation techniques, strategies to protect crops from diseases, and understand which type of seed varieties to use to avoid crop loss. The present review briefly discusses the coffee cultivation techniques, impact of climate changes on coffee production, processing techniques of coffee, and the importance of coffee in our society, including its chemical composition and prevention against, major diseases. Furthermore, the importance and role of advanced nanotechnology along with molecular approaches for coffee crop improvement and facing challenges are explained.
Aquaporin proteins are very important for water transport across the plasma membrane. In this study, the plasma membrane intrinsic protein PIP2;7 cloned from Saussurea involucrata was overexpressed in Arabidopsis thaliana. Transgenic lines showed rapid growth, with increased leaf numbers and leaf sizes, due to high rates of photosynthesis, transpiration, and stomatal conductance. Moreover, SiPIP2;7 conferred drought resistance in Arabidopsis by improving water use efficiency and intracellular osmotic pressure via a decrease in the stomatal density and increases in intracellular Cl⁻. These phenotypes were attributed to the effects of SiPIP2;7 on the relative expression levels of target genes related to the stomatal development and ion transport. Moreover, SiPIP2;7 gene improve drought resistance and fruit yield of tomato. These results indicated that the SiPIP2;7 gene is effective for breeding new varieties with high drought resistance and yield.
This review was focused on agronomic practices influenced negative impacts of climate change. Coffee is the only crop which more than 25 million people in the world depend on, and the second most important commodity next to oil. However, in recent decades, coffee production has been influenced by severity of climatic changes. Agronomic practices have great function in sustain coffee production due to their attribution in buffering climatic change. Thus, this review conducted with the intension of agronomic practices task in buffering of climatic change impacts in coffee production and productivity. Because of climate change, the optimum production zone for coffee is projected to decrease up to 40% and at the end of this century, temperature will rise by 4-6°C. This severity and hazardless will tremendous in developing countries which extremely vulnerable to the risk. Furthermore, deforestation due to over population and absence of awareness in agroforestry are another problem increases the risk of climate change. Familiarity of contributions of agronomic practices in mitigating climate change is less recognizing and practiced informally than improve and scientific way. However, shading has capacity to reduce air temperature by 4°C, banana intercropping with coffee contributed as sources of income in off season for coffee yield. Finally, agronomic practices such as shading, mulching, irrigation, intercropping, pruning and soil conservation practices are the best option for sustaining coffee production and for buffering the direct and indirect impacts of climatic changes.
Crop production faces many challenges, due to changing environmental conditions and evolving needs for new plant-derived materials. Soil water deficit, a consequence of present-day global climate changes, is considered as major environmental limitation for crop plants. Different studies clearly show that soil water deficit substantially influences the metabolism, viability, physiology, dry matter production, dry matter partitioning, and yield of many plants. The effect of soil water deficit on the dry matter production and growth rate varies with phonological stage and intensity of water deficit. Dry matter accumulation is a complex process, under a strong influence of the environment, cultivar and their interaction. The accumulation of crop biomass follows a typical sigmoid pattern. Total dry matter production is a good estimator of the degree of adaptation of a genotype to the environment in which it is grown. Differences in total dry matter accumulation in genotypes reflect differences in photosynthetic production. Partitioning of assimilated carbon among sink organs is a critical factor that controls the rate and pattern of plant growth. Soil water deficit not only limits the size of the source and sink tissues but the phloem loading, assimilate translocation, and dry matter portioning are also impaired. However, the extent of effects varies with the plant species, stage, duration, and severity of water deficit. Plants exposed to soil water deficit show a common response however, the extent of damage caused by water deficit depends greatly on the duration of the water shortage, the genotypes of the exposed plants, and their stage of growth. There is ample need to develop soil water deficit tolerance in crop plants by exploring suitable strategies. The development of genetically engineered plants, by the introduction and/or overexpression of selected genes, would be one feasible strategy. However, plant adaptation to soil water deficit is a multigenic response which is very complex in nature. Thus the task of identifying the traits that correlate with stress tolerance is incredibly difficult for researchers.
Plants in nature are continuously exposed to several biotic and environmental limitations. Among these limitations, soil water deficit is one of the most adverse factors of plant growth and productivity and is considered a severe threat for sustainable crop production in the conditions of changing climate. Scarcity of water is a severe environmental constraint to plant productivity. Soil water deficit-induced loss in crop yield probably exceeds losses from all other causes, since both the severity and duration of the limitations are critical. Various management strategies have been proposed to cope with soil water deficit. Soil water deficit reduces leaf size, stem extension, and root proliferation, disturbs plant–water relations, and reduces water use efficiency. Plants display a variety of physiological and biochemical responses at cellular and whole-organism levels towards prevailing soil water deficit, thus making it a complex phenomenon. CO2 assimilation by leaves is reduced mainly by stomatal closure, membrane damage, and disturbed activity of various enzymes, especially those of CO2 fixation and adenosine triphosphate synthesis. Low molecular weight osmolytes, including glycine betaine, proline, and other amino acids, organic acids, and polyols are crucial to sustain cellular functions under soil water deficit. Plant growth substances such as salicylic acid, auxins, gibberellins, cytokinins, and abscisic acid modulate the plant responses towards soil water deficit. Polyamines, citrulline, and several enzymes act as antioxidants and reduce the adverse effects of water deficit. Soil water deficit is a multidimensional phenomenon affecting plants at various levels of their organization. The effect of and plant response to soil water deficit at the whole plant and crop level is most complex because it reflects the integration of these environmental limitation effects and responses at all underlying levels of organization over space and time.
Drought is among the major factors that adversely affect coffee production in most parts of Ethiopia. Hararghe coffee is despite its economic importance in the world market and in the national economy of the country; its productivity is very low primarily because of periodic soil moisture deficit stresses and many other factors. Therefore, this experiment was conducted to screen and evaluate Hararghe coffee genotypes for drought tolerant in response to soil moisture stresses. A total of nineteen coffee genotypes; fourteen promising coffee selections and five released varieties were evaluated for morphological and physiological drought stress traits using Completely Randomized Design with three replications. The experiment was conducted at Mechara Agricultural Research Center in a rain shelter. Eight pairs of true leaf coffee seedlings were subjected to two watering regimes (water-stress by withholding irrigation and well-watered control). The analysis of variance results revealed significant variation among coffee genotypes for water deficit stress. Therefore, based on preliminary observations and visual assessments of recovery plants, the genotypes were grouped into three categories of drought tolerance; sensitive, moderately sensitive and relatively tolerant. However, genotypes from each category should also be tested for their morphological, physiological and biochemical responses to drought in order to identify more tolerant types and come up with a recommendation for further selection and breeding works for drier coffee growing areas of the country.
Droughts are major natural disasters that affect many parts of the world all years and recently
affected one of the major conilon coffee-producing regions of the world in state of Espírito Santo,
which caused a huge crisis in the sector. Therefore, the objective of this study was to conduct an
analysis with technical-scientific basis of the real impact of drought associated with high temperatures
and irradiances on the conilon coffee (Coffea canephora Pierre ex Froehner) plantations located in the
north, northwest, and northeast regions of the state of Espírito Santo, Brazil. Data from 2010 to 2016
of rainfall, air temperature, production, yield, planted area and surface remote sensing were obtained
from different sources, statistically analyzed, and correlated. The 2015/2016 season was the most
affected by the drought and high temperatures (mean annual above 26 °C) because, in addition to the
adverse weather conditions, coffee plants were already damaged by the climatic conditions of the
previous season. The increase in air temperature has higher impact (negative) on production than the
decrease in annual precipitation. The average annual air temperatures in the two harvest seasons that
stood out for the lowest yields (i.e. 2012/2013 and 2015/2016) were approximately 1 °C higher than in
the previous seasons. In addition, in the 2015/2016 season, the average annual air temperature was
the highest in the entire series. The spatial and temporal distribution of Enhanced Vegetation Index
values enabled the detection and perception of droughts in the conilon coffee-producing regions of
Espírito Santo. The rainfall volume accumulated in the periods from September to December and
from April to August are the ones that most affect coffee yield. The conilon coffee plantations in these
regions are susceptible to new climate extremes, as they continue to be managed under irrigation
and full sun. The adoption of agroforestry systems and construction of small reservoirs can be useful
to alleviate these climate effects, reducing the risk of coffee production losses and contributing to the
sustainability of crops in Espírito Santo.
Maize is a staple cereal after wheat and rice. It is an important source of carbohydrate, protein, iron, vitamin B and minerals for many poor people in the world. In developing countries maize is a major source of income in resource-poor farmers. As maize is used both as silage and as crop residue and the grains of maize are usually used for food, starch and oil extraction industrially, the demand for maize is rising day by day. Therefore, it is imperative for improvement of maize to meet the increasing demand. This book entitled "Maize - Production and Use" highlights the importance of maize and the improved management approaches for improving the productivity of maize in the era of changing climate.
Overall, drought and unfavourable temperatures are the major climatic limitations for coffee production. These limitations are expected to become increasingly important in several coffee growing regions due to the recognized changes in global climate, and also because coffee cultivation has spread towards marginal lands, where water shortage and unfavourable temperatures constitute major constraints to coffee yield. In this review, we examine the impacts of such limitations on the physiology, and consequently on the production of mainly Coffea arabica and C. canephora, which account for about 99 % of the world coffee bean production. The first section deals with climatic factors and the coffee plant’s requirements. The importance of controlling oxidative stress for the expression of drought and cold tolerance abilities is emphasized in the second section. In the third section, we examine the impacts of drought on cell-water relations, stomatal behaviour and water use, photosynthesis and crop yield, carbon and nitrogen metabolism, root growth and characteristics, and on drought tolerance. In the fourth section, the impacts of low positive and high temperatures on coffee physiology are discussed; some insights about effects of negative temperatures are also presented. Finally, the last section deals with shading in harsh environments as a mean of buffering climatic fluctuations, as well as of increasing environmental sustainability in coffee exploitation.
Influence of short-term water stress on plant growth and leaf gas exchange was studied simultaneously in a growth chamber experiment using two annual grass species differing in photosynthetic pathway type, plant architecture and phenology:Triticum aestivum L. cv. Katya-A-1 (C3, a drought resistant wheat cultivar of erect growth) andTragus racemosus (L.) All. (C4, a prostrate weed of warm semiarid areas). At the leaf level, gas exchange rates declined with decreasing soil water potential for both species in such a way that instantaneous photosynthetic water use efficiency (PWUE, mmol CO2 assimilated per mol H2O transpired) increased. At adequate water supply, the C4 grass showed much lower stomatal conductance and higher PWUE than the C3 species, but this difference disappeared at severe water stress when leaf gas exchange rates were similarly reduced for both species. However, by using soil water more sparingly, the C4 species was able to assimilate under non-stressful conditions for a longer time than the C3 wheat did. At the whole-plant level, decreasing water availability substantially reduced the relative growth rate (RGR) ofT. aestivum, while biomass partitioning changed in favour of root growth, so that the plant could exploit the limiting water resource more efficiently. The change in partitioning preceded the overall reduction of RGR and it was associated with increased biomass allocation to roots and less to leaves, as well as with a decrease in specific leaf area. Water saving byT. racemosus sufficiently postponed water stress effects on plant growth occurring only as a moderate reduction in leaf area enlargement. For unstressed vegetative plants, relative growth rate of the C4
T. racemosus was only slightly higher than that of the C3
T. aestivum, though it was achieved at a much lower water cost. The lack of difference in RGR was probably due to growth conditions being relatively suboptimal for the C4 plant and also to a relatively large investment in stem tissues by the C4
T. racemosus. Only 10% of the plant biomass was allocated to roots in the C4 species while this was more than 30% for the C3 wheat cultivar. These results emphasize the importance of water saving and high WUE of C4 plants in maintaining growth under moderate water stress in comparison with C3 species.
Eight perennial C-4 grasses from the Jornada del Muerto Basin in southern New Mexico show five-fold differences in relative
growth rates under well- watered conditions (RGRmax). In a controlled environment, we tested the hypothesis that there is an inverse relationship (trade-off) between RGRmax and the capacity of these species to tolerate drought. We examined both physiological (gas exchange) and morphological (biomass
allocation, leaf properties) determinants of growth for these eight species under three steady-state drought treatments (none=control,
moderate, and severe). When well watered, the grasses exhibited a large interspecific variation in growth, which was reflected
in order-of-magnitude biomass differences after 5 weeks. The species had similar gas-exchange characteristics, but differed
in all the measured allocation and morphological characteristics, namely tiller mass and number, root:shoot ratio, dry-matter
content, and specific leaf area (SLA). Drought affected tillering, morphology, and allocation, and reduced growth by 50 and
68% (moderate and severe drought, respectively) compared to the well-watered controls. With the exception of SLA, none of
these variables showed a significant species-by-treatment interaction. We calculated three indices of drought tolerance, defined
as the ratio in final biomass between all the possible ”dry”/”wet” treatment pairs: severe/moderate, moderate/control, and
severe/control. We found no significant correlation between these drought tolerance indices, on the one hand, and three indices
of growth potential (greenhouse RGRmax, final biomass in the control treatment, and final:initial biomass ratio in controls), on the other. Based on these controlled-environment
results, we hypothesize that the commonly reported correlation between plant growth potential and drought tolerance in the
field may in some cases be explained by differential effects of plants on soil-water content rather than by differences in
species responses to drought.
Growth, photosynthesis and water use efficiency of two Sahel dominant C4grasses:Schoenefeldia gracilis Kunth and Dactyloctenium aegyptium (L) P. Beauv were studied under well-watered and drought conditions. D. aegyptium had a faster rate of development than S. gracilis and responded to water-deficits by decreasing leaf area in the earlier stages of development. However, under water-stress the overall reduction of leaf area suffered by S. gracilis was greater than in D. aegyptium. The decrease in net photosynthesis observed under water-deficits resulted mainly from stomatal closure. Analysis of correlation between long-term water-use efficiency and several physiological, structural and growth characteristics shows that long-term water-use efficiency in D. aegyptium was positively correlated with relative growth rates. The reduction in growth resulting from water-deficits was compensated by an increase in the short-term water-use efficiency associated with stomatal closure. In S. gracilis, the long-term water-use efficiency under moderate water-deficits increased but was not positively correlated with relative growth rate; it was associated with a high allocation to non-photosynthetic (support and vascular) tissues. The possible implications of this behaviour for the different ‘strategies’ for plant survival in the arid climate of the Sahel are discussed.
The allocation of biomass to different plant organs depends on species, ontogeny and on the environment experienced by the plant. In this paper we first discuss some methodological tools to describe and analyse the allocation of biomass. Rather than the use of shoot:root ratios, we plead strongly for a subdivision of biomass into at least three compartments: leaves, stems and roots. Attention is drawn to some of the disadvantages of allometry as a tool to correct for size differences between plants. Second, we tested the extent to which biomass allocation of plants follows the model of a 'functional equilibrium'. According to this model, plants respond to a decrease in above-ground resources with increased allocation to shoots (leaves), whereas they respond to a decrease in below- ground resources with increased allocation to roots. We carried out a meta-analysis of the literature, analysing the effect of various environmental variables on the fraction of total plant biomass allocated to leaves (leaf mass fraction), stem (stem mass fraction) and roots (root mass fraction). The responses to light, nutrients and water agreed with the (qualitative) prediction of the 'functional equilibrium' theory. The notable exception was atmospheric CO2, which did not affect allocation when the concentration was doubled. Third, we analysed the quantitative importance of the changes in allocation compared to changes in other growth parameters, such as unit leaf rate (the net difference between carbon gain and carbon losses per unit time and leaf area), and specific leaf area (leaf area: leaf biomass). The effects of light, CO2 and water on leaf mass fractions were small compared to their effects on relative growth rate. The effects of nutrients, however, were large, suggesting that only in the case of nutrients, biomass allocation is a major factor in the response of plants to limiting resource supply.
This paper briefly reviews some selected traits (leaf area, crown architecture, water-use efficiency and carbon isotope discrimination, water relations and root characteristics), which may be explored in breeding programmes to tolerance to drought stress in arabica and robusta coffee.
Effects of water supply on gas exchange, carbon isotopic composition, and relative growth rate were compared among seedlings from three populations of ponderosa pine (Pinus ponderosa Dougl. ex Laws.) grown in a controlled environment chamber. The three populations were chosen to represent high, moderate and low drought tolerance. There was no indication that drought tolerance was related to high water-use efficiency. Populations differed (P < 0.05) in relative growth rate (RGR), but did not differ (P > 0.10) in gas exchange variables or carbon isotope ratio (delta(13)C). Well-watered seedlings had significantly higher RGR, xylem pressure potential (Psi(xpp)), net photosynthesis (A), stomatal conductance to water vapor (g), and lower delta(13)C and instantaneous water-use efficiency than water-stressed seedlings. With decreasing Psi(xpp), A decreased linearly, whereas g decreased exponentially. Seedlings of the highly drought-tolerant population were more sensitive to water availability than seedlings from the other populations; they used water quickly when water was available, but closed their stomata in response to water stress. We conclude that, in ponderosa pine, the drought avoidance mechanism is more important for survival and growth in arid and semiarid environments than the efficient use of water.
To investigate the effects of soil water content on growth and transpiration of Japanese cedar (Cryptomeria japonica D. Don) and Hinoki cypress (Chamaecyparis obtusa (Siebold et Zucc.) Endl.), potted seedlings were grown in well-watered soil (wet treatment) or in drying soil (dry treatment)
for 12 weeks. Seedlings in the wet treatment were watered once every 2 or 3 days, whereas seedlings in the dry treatment were
watered when soil water content (Θ; m3 m−3) reached 0.30, equivalent to a soil matric potential of −0.06 MPa. From Weeks 7 to 12 after the onset of the treatments,
seedling transpiration was measured by weighing the potted seedlings. After the last watering, changes in transpiration rate
during soil drying were monitored intensely. The dry treatment restricted aboveground growth but increased biomass allocation
to the roots in both species, resulting in no significant treatment difference in whole-plant biomass production. The species
showed similar responses in relative growth rate (RGR), net assimilation rate (NAR) and shoot mass ratio (SMR) to the dry
treatment. Although NAR did not change significantly in either C. japonica or C. obtusa as the soil dried, the two species responded differently to the dry treatment in terms of mean transpiration rate (E) and water-use efficiency (WUE), which are parameters that relate to NAR. In the dry treatment, both E and WUE of C. japonica were stable, whereas in C. obtusa, E decreased and WUE increased (E and WUE counterbalanced to maintain a constant NAR). Transpiration rates were lower in C. obtusa seedlings than in C. japonica seedlings, even in well-watered conditions. During soil drying, the transpiration rate decreased after Θ reached about 0.38
(−0.003 MPa) in C. obtusa and 0.32 (−0.028 MPa) in C. japonica. We conclude that C. obtusa has more water-saving characteristics than C. japonica, particularly when water supply is limited.
Container-grown seedlings of Acacia tortilis Forsk. Hayne and A. xanthophloea Benth. were watered either every other day (well watered) or every 7 days (water-stressed) for 1 year in a greenhouse. Total plant dry mass (T(dm)), carbon allocation and water relations were measured monthly. Differences in leaf area (LA) accounted for differences in T(dm) between the species, and between well-watered and water-stressed plants. Reduction in LA as a result of water stress was attributed to reduced leaf initiation, leaf growth rate and leaf size. When subjected to prolonged water stress, Acacia xanthophloea wilted more rapidly than A. tortilis and, unlike A. tortilis, lost both leaves and branches. These differences between species were attributed to differences in the allocation of carbon between leaves and roots and in the ability to adjust osmotically. Rapid recovery in A. xanthophloea following the prolonged water-stress treatment was attributed to high cell wall elasticity. Previous exposure to water stress contributed to water-stress resistance and improved recovery after stress.
Effects of water availability on seedling growth were analysed in eight Mediterranean species naturally occurring in the Balearic Islands. Seedlings were grown outdoors during summer under two irrigation treatments: field capacity and 35% of field capacity. The relative growth rate (RGR) strongly depended on the growth form, from highest values in herbs to lowest in woody perennials. The main component associated with interspecific variation in RGR was the specific leaf area (SLA), and a quantitative grouping of the different growth forms appeared along the regression line between both parameters. The slow-growing species, i.e. woody perennial shrubs, had the lowest SLA and the fast-growing perennial herbs, the highest, while woody semi-deciduous shrubs appeared intermediate. Decreases in RGR due to water stress were analysed in terms of the relative contribution of the leaf mass ratio (LMR), SLA and the net assimilation rate (NAR). Pooling all species, the decrease in RGR caused by water deficit was mainly explained by decreases in SLA. However, this general pattern was strongly dependent of growth form. Thus, in the woody perennial plants, the decrease in RGR was accompanied by a three-fold decrease in NAR which, however, increased in perennial herbs. SLA increased with decreasing water supply in woody perennial plants, and decreased in woody semi-deciduous shrubs and perennial herbs. Finally, decreases in LMR partly explained decreases in RGR in perennial herbs and woody perennial shrubs. This different response of the different growth forms may reflect differences in seedling adaptation and surviving strategies to drought periods.
*
Drought is a major environmental constraint affecting growth and production of Coffea canephora. Selection of C. canephora clones has been largely empirical as little is known about how clones respond physiologically to drought. Using clones previously shown to differ in drought tolerance, this study aimed to identify the extent of variation of water use and the mechanisms responsible, particularly those associated morphological traits. *
Clones (14 and 120, drought-tolerant; 46 and 109A, drought-sensitive, based on their abilities to yield under drought) were grown in 120-L pots until they were 12-months old, when an irrigation and a drought treatment were applied; plants were droughted until the pressure potential (psi(x)) before dawn (pre-dawn) reached -3.0 MPa. Throughout the drought period, psi(x) and stomatal conductance (g(s)) were measured. At the end of the experiment, carbon isotope ratio and parameters from pressure-volume curves were estimated. Morphological traits were also assessed. *
With irrigation, plant hydraulic conductance (K(L)), midday psi(x) and total biomass were all greater in clones 109A and 120 than in the other clones. Root mass to leaf area ratio was larger in clone 109A than in the others, whereas rooting depth was greater in drought-tolerant than in drought-sensitive clones. Predawn psi(x) of -3.0 MPa was reached fastest by 109A, followed progressively by clones 46, 120 and 14. Decreases in g(s) with declining psi(x), or increasing evaporative demand, were similar for clones 14, 46, and 120, but lower in 109A. Carbon isotope ratio increased under drought; however, it was lower in 109A than in other clones. For all clones, psi(x), g(s) and K(L) recovered rapidly following re-watering. Differences in root depth, K(L) and stomatal control of water use, but not osmotic or elastic adjustments, largely explained the differences in relative tolerance to drought stress of clones 14 and 120 compared with clones 46 and 109A.
Photosynthetic gas exchange, plant-water relations characteristics, and stable carbon isotope discrimination (Delta) were evaluated for five Coffea arabica L. genotypes growing under two soil moisture regimes in the field. The Delta of leaf tissue was strongly correlated (r = -0.95) with inherent water use efficiency (ratio of assimilation to stomatal conductance; A/g). The variation in inherent water use efficiency (WUE) among genotypes was 30% for plants irrigated weekly. The higher WUE exhibited by some of these plants resulted from reduced g rather than increased photosynthetic capacity at a given g. Withholding irrigation for 1 month caused Delta to decline substantially in expanding leaf tissue of all genotypes. A strong correlation (r = 0.92) was found between Delta and plant hydraulic efficiency estimated as the ratio of g to the diurnal range in leaf water potential (Psi(l)). The Delta values for plants irrigated weekly adequately predicted drought-induced changes in Delta (r = 0.99) and midday Psi(l) (r = 0.95). The results indicated that Delta might be used to evaluate several aspects of plant performance and response to specific environmental conditions, once suitable background physiological data have been gathered.
The allocation of biomass to different plant organs depends on species, ontogeny and on the environment experienced by the plant. In this paper we first discuss some methodological tools to describe and analyse the allocation of biomass. Rather than the use of shoot:root ratios, we plead strongly for a subdivision of biomass into at least three compartments: leaves, stems and roots. Attention is drawn to some of the disadvantages of allometry as a tool to correct for size differences between plants. Second, we tested the extent to which biomass allocation of plants follows the model of a 'functional equilibrium'. According to this model, plants respond to a decrease in above-ground resources with increased allocation to shoots (leaves), whereas they respond to a decrease in below-ground resources with increased allocation to roots. We can-led out a meta-analysis of the literature, analysing the effect of various environmental variables on the fraction of total plant biomass allocated to leaves (leaf mass fraction), stem (stem mass fraction) and roots (root mass fraction). The responses to light, nutrients and water agreed with the (qualitative) prediction of the 'functional equilibrium' theory. The notable exception was atmospheric CO2, which did not affect allocation when the concentration was doubled. Third, we analysed the quantitative importance of the changes in allocation compared to changes in other growth parameters, such as unit leaf rate (the net difference between carbon gain and carbon losses per unit time and leaf area), and specific leaf area (leaf area: leaf biomass). The effects of light, CO2 and water on leaf mass fractions were small compared to their effects on relative growth rate. The effects of nutrients, however, were large, suggesting that only in the case of nutrients, biomass allocation is a major factor in the response of plants to limiting resource supply.
Coffee plants of five Arabica and one Canephora genotypes were raised in containers with 0.02 nr1 of soil, under a clear plastic shelter. When they were 18 months old, irrigation was withheld until the first signs of wilting appeared. This occurred four to five days after withholding irrigation, when the pre-dawn water potential of young fully expanded leaves of the plagiotropic branches was about -2.4 MPa. Control plants remained under daily irrigation. The pressure-volume technique was used to estimate volume averaged water relations properties of sample leaves. The turgor loss point was approximately -1.6 MPa for control plants and -2.0 MPa for stressed plants, an osmotic adjustment of approximately 22%. The Canephora genotype showed a slightly higher adjustment. The relative water content at the turgor loss point remained at approximately 93%, irrespective of genotype or treatment. The maximum bulk modulus of elasticity did not change significantly with water deficit, remaining at about 24 MPa, except for a slight increase in the Canephora genotype. The specific leaf area of the Arabica genotypes decreased about 20%, as compared with a 10% decrease for the Canephora genotype.
Foliar C isotope discrimination (Δ) and yield of green coffee (Coffea arabica L.) beans were evaluated for seedling populations from 14 diverse coffee cultivars growing in Hawaii. A was negatively correlated with yield of green coffee beans. The 2% variation in A observed in leaves sampled about 2 months after completion of the first harvest corresponded to a 3-fold variation in yield. Substantial variation in A exists among coffee cultivars, and foliar A analyses show promise as a means of selecting superior genotypes of long-lived woody crops.
Publisher Summary The potential for increased irrigation is limited, so that future population increases will need to be fed from higher food production per unit land area and without the aid of increased irrigation resources. Thus, for improved food production, rainfall and irrigation water will be used more efficiently and the importance of understanding and managing crop water deficits is a necessity. Clearly, improving the drought resistance of our food and fiber crops is of strategic importance and progress should be sustained. Although the new technologies of genetic engineering hold considerable promise, they will need to be coupled to traditional breeding and agronomy if these new technologies are to be fully utilized. In this chapter, the development of ideas and methodologies that have emerged during the past decade are reviewed and evaluated.
A method of length estimation based on Newman's (1966) line intersect principle was developed and tested during a programme of root growth investigation in wheat. The length of sample roots when spread over a flat surface was found to relate to the number of intercepts made with the vertical and horizontal lines of an underlying grid. The versatility of the method was tested using 1/2 × 1/2, 1 × 1, 2 × 2 and 3 × 3 cm grid square sizes. Length estimates to 10 m required a maximum of 5-6 min for coefficients of variation of 5% or less.
In environments where the amount of water is limiting growth, water-use efficiency (biomass production per unit water use) is an important trait. We studied the relationships of plant growth and water use efficiency with the pattern of biomass allocation, using 10 wheat cultivars, grown at two soil moisture levels in a growth chamber. Allocation pattern and relative growth rate were not correlated, whereas allocation pattern and water use efficiency were. Variation in transpiration per plant resulted from variation in the rate of transpiration per unit leaf area or root weight, rather than from differences in leaf area or root weight per plant. Transpiration per unit leaf area or root weight was lower when the leaf area or root weight per unit plant weight was larger. Also, the efficiency of water use at the plant and leaf levels was higher for plants with a higher leaf area per unit plant weight, and it was not correlated with the plant’s growth rate. Differences in water-use efficiency at the leaf level were related to variation in stomatal conductance, rather than in the rate of photosynthesis. A high photosynthetic water-use efficiency was associated with a low efficiency of nitrogen use for photosynthesis.
The impact of seed size on germination and seedling growth, as affected by water stress, was studied for five tree species from tropical dry forest of India, viz. Albizia
procera,
Acacia
nilotica,
Phyllanthus
emblica,
Terminalia
arjuna and Terminalia
chebula. Germination tests were conducted under five osmotic potential levels. Seedlings from large (LS) and small (SS) seeds were grown at four soil moisture levels. Observations were made on height, leaf area, biomass and other growth traits such as relative growth rate (RGR), net assimilation rate (NAR), specific leaf area (SLA), and root:shoot (R:S) ratio. Seeds of pioneer species and large seeds, within species, germinated earlier, and with increasing water stress, per cent germination and germination velocity declined. RGR was inversely related with drought tolerance. R:S ratio increased, RGR and SLA declined, but NAR increased with water stress. Notwithstanding successional status, the slow-growing species registered minimum reduction in biomass due to water stress. The response of LS and SS seedlings also differed for some of the growth variables. Increase in NAR could be a compensatory response to water stress, and the marked allocational plasticity could help maximize capture of the limited resource. Seedlings from smaller seeds, particularly of fast-growing species, would be able to cope with mild drought by morphogenetic and physiological plastic response in a better way than those from large seeds. However, seedlings from large seeds had greater survival than those from smaller seeds under intense water stress.
Improvements in drought tolerance of crop plants require research focused on physiological processes. In 2002 and 2003 pot experiments with sugar beet were conducted in a greenhouse. Two (2002) or three (2003) different genotypes were subjected to three watering regimes (100, 50 and 20% of water holding capacity). Gas exchange, chlorophyll fluorescence and water-use efficiency (WUE) as parameters of possible relevance for drought stress tolerance in sugar beet were investigated. It was studied whether 13C discrimination (Δ) is suitable as an indirect measure for WUE of sugar beet.DM yield, photosynthesis rate, transpiration rate and stomatal conductance decreased with increasing severity of drought stress. In contrast, internal CO2 partial pressure remained relatively stable and effective quantum yield of photosynthesis was reduced only under severe drought, which points at non-stomatal inhibition of photosynthesis. Different sugar beet genotypes showed significant differences in DM yield, but interactions between genotype and water supply did not occur, indicating that genotypic differences in drought tolerance did not exist. In accordance with that, drought-sensitivity of gas exchange and chlorophyll fluorescence was the same in different genotypes. Δ was higher in the leaves than in the taproot. Reductions in Δ in drought-stressed plants corresponded to about 24% higher WUE. Differentiating between plant organs, only leaf Δ was negatively correlated with WUEL whereas taproot Δ and WUET were unrelated. Δ was therefore proven to be a sensitive indicator for water availability during the growing period. However, similar as other parameters relevant for drought stress tolerance it requires investigations in broader genetic material of sugar beet to detect genotypic differences.
1. To test hypotheses concerning adaptation and acclimation of tree species to shaded habitats we determined the growth, biomass partitioning and morphology of seedlings of nine near-boreal tree species in high- and low-light greenhouse environment (25 and 5% of full sunlight, respectively), comparable to sunlit gap and shaded microsites in boreal forests. The species differ widely in shade tolerance, seed size and leaf life span.
2. In low light, all species allocated proportionally more biomass to stems and less to roots, but the same to foliage, compared with the high-light environment. At a common size, all species had finer leaf morphology (higher specific leaf area, SLA) but coarser root morphology (lower specific root length, SRL) in low than high light. From a whole plant perspective, all species enhanced leaf area per unit plant mass (leaf area ratio, LAR) in low light and root length per unit plant mass (root length ratio, RLR) in high light.
3. Shade-intolerant deciduous species had higher RGR, SLA and SRL than larger seeded evergreens: ranking from Populus, Betula and Larix spp., then to five evergreen Pinus, Picea and Thuja spp., which were generally comparable in these traits. There were no changes in growth rankings of species between high- and low-light environments, nor consistent differences among species in biomass partitioning. Hence, species differences in leaf and root morphology (SLA, SRL) drove whole plant patterns, such as Populus, Betula and Larix had greater total leaf area and root length per unit plant mass (LAR and RLR, respectively) than the evergreens. Interspecific variation in RGR in both high and low light was positively correlated (r≈ 0·9) with SLA, SRL, LAR and RLR, and negatively correlated (r≈–0·9) to seed mass and leaf life span.
4. These data suggest that SLA, SRL, NAR and RGR are closely associated with variation in life-history traits and that variation in leaf and root structure more strongly influences patterns of RGR among species and light environments than does biomass partitioning.
Everyone who grows plants, whether a single geranium in a flower pot or hundreds of acres of corn or cotton, is aware of the importance of water for successful growth. Water supply not only affects the yield of gardens and field crops, but also controls the distribution of plants over the earth's surface, ranging from deserts and grasslands to rain forests, depending on the amount and seasonal distribution of precipitation. However, few people understand 'fully why water is so important for plant growth. This book attempts to explain its importance by showing how water affects the physiological processes that control the quantity and quality of growth. It is a useful introduction for students, teachers, and investigators in both basic and applied plant science, including botanists, crop scientists, foresters, horticulturists, soil scientists, and even gardeners and farmers who desire a better understanding of how their plants grow. An attempt has been made to present the information in terms intelligible to readers with various backgrounds. If the treatment of some topics seems inadequate to specialists in certain fields, they are reminded that the book was not written for specialists, but as an introduction to the broad field of plant water relations. As an aid in this respect, a laboratory manual is available with detailed instructions for some of the more complex methods (J. S. Boyer in "Measuring the Water Status of Plants and Soils," Academic Press, San Diego, 1995).
We examined the relationships among productivity, water use efficiency (WUE) and drought tolerance in 29 genotypes of Populus x euramericana (Populus deltoides x Populus nigra), and investigated whether some leaf traits could be used as predictors for productivity, WUE and drought tolerance. At Orléans, France, drought was induced on one field plot by withholding water, while a second plot remained irrigated and was used as a control. Recorded variables included stem traits (e.g. biomass) and leaf structural (e.g. leaf area) and functional traits [e.g. intrinsic water use efficiency (Wi) and carbon isotope discrimination (Delta)]. Productivity and Delta displayed large genotypic variability and were not correlated. Delta scaled negatively with Wi and positively with stomatal conductance under moderate drought, suggesting that the diversity for Delta was mainly driven by stomatal conductance. Most of the productive genotypes displayed a low level of drought tolerance (i.e. a large reduction of biomass), while the less productive genotypes presented a large range of drought tolerance. The ability to increase WUE in response to water deficit was necessary but not sufficient to explain the genotypic diversity of drought tolerance.
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