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Differential responses in water use efficiency in two varieties of Catharanthus roseus under drought stress
Abstract
Two varieties, rosea and alba, of Catharanthus roseus (L.) G. Don. were screened for their water use efficiency under two watering regimes, viz. 60 and 100% filed capacity in the present study. Drought stress was imposed at 60% filed capacity from 30 to 70 days after sowing, while the control pots were maintained at 100% filed capacity throughout the entire growth period. Leaf area duration, cumulative water transpired, water use efficiency, net assimilation rate, mean transpiration rate, harvest index, biomass and yield under the water deficit level were measured from both stressed and well-watered control plants. Water use efficiency significantly increased in both varieties under water stress. Drought stress decreased leaf area duration, cumulative water transpired, net assimilation rate, mean transpiration rate, harvest index, and biomass yield in both varieties studied. Among the varieties, rosea variety showed the best results.
... Root vegetables, including sugar beets (Sabreen et al. 2018), carrots (Zhang et al. 2021), and radishes (Henschel et al. 2022;Stagnari et al. 2018), experience reduced growth and biomass allocation among their organs when faced with water deficiency. Water scarcity often leads to an excess of reactive oxygen species (ROS), causing oxidative stress (Chaichi et al. 2017;Jaleel et al. 2008;Martinez et al. 2016;Shahid et al. 2020), which can harm proteins, RNA, DNA, and biological membranes. To counteract this, plants use enzymatic and nonenzymatic antioxidant systems to detoxify and regulate cellular ROS levels (Devireddy et al. 2021;Miller et al. 2010). ...
... Water deficit limits CO 2 assimilation and stomatal conductance (Miyashita et al. 2005;Sabreen et al. 2018); however, in our study, the application of 75% and 100% compost significantly improved these parameters. WUE indicates the ratio of water used in metabolic processes to the water lost via transpiration, and it has been reported to increase with increasing drought levels (Jaleel et al. 2008;Liu and St€ utzel 2004). In addition, compost amendment has been shown to significantly enhance WUE (Abd El-Mageed et al. 2018;Jaleel et al. 2008); however, compost amendment effects can vary due to factors such as compost quality, application rates, crop type, and environmental conditions. ...
... WUE indicates the ratio of water used in metabolic processes to the water lost via transpiration, and it has been reported to increase with increasing drought levels (Jaleel et al. 2008;Liu and St€ utzel 2004). In addition, compost amendment has been shown to significantly enhance WUE (Abd El-Mageed et al. 2018;Jaleel et al. 2008); however, compost amendment effects can vary due to factors such as compost quality, application rates, crop type, and environmental conditions. Different compost amendments have been found to have varying effects on soil characteristics and plant growth. ...
Red radish is a nutritious root vegetable crop that has a short production cycle. Water deficit limits plant productivity, affecting its quantity and quality. Compost amendment offers a potential solution to mitigate water deficit effects. This study assessed the impact of compost manure rates (0%, 50%, 75%, and 100%) and irrigation treatments (40%, 60%, 80%, and 100% of evapotranspiration) on ‘Crimson Giant’ red radish production. Significant differences in growth and quality were observed among these treatments. Compost rates of 75% and 100% improved leaf gas exchange, plant growth (leaf count, fresh weight, dry weight, and area; stem length), root development, total yield (root fresh weight, dry weight, diameter, and length), and root quality (vitamin C and total soluble solid and titratable acidity). The 100% compost and 100% irrigation combination achieved the highest yields. Under water deficit, applying 75% or 100% compost with 80% irrigation conserved 20% of water while maintaining radish output. Overall, compost amendment effectively enhanced red radish growth and production under water deficit.
... moisture stress, high temperature, imbalance nutrition etc.). Severe moisture may result in the arrest of photosynthesis, disturbance of metabolism and finally death of plant (Jaleel et al. 2008) [12] . Commercial crops like onion are exposed to a wide array of damaging agents, including biotic (viruses, bacteria, fungi, insects) and abiotic (drought, salinity, heat, cold, soil toxicity) environmental aggressions. ...
... moisture stress, high temperature, imbalance nutrition etc.). Severe moisture may result in the arrest of photosynthesis, disturbance of metabolism and finally death of plant (Jaleel et al. 2008) [12] . Commercial crops like onion are exposed to a wide array of damaging agents, including biotic (viruses, bacteria, fungi, insects) and abiotic (drought, salinity, heat, cold, soil toxicity) environmental aggressions. ...
... The responses of plants to water stress vary significantly depending on the intensity and duration of the stress, as well as on the plant species and its stage of growth [63]. Water deficit significantly influenced the growth and development of the aboveground components, including plant height, leaf area, and leaf greenness, during the early vegetative phase of this study. ...
... Morphological responses of maize under water stress The responses of plants to water stress vary significantly depending on the intensity and duration of the stress, as well as on the plant species and its stage of growth [63]. Water deficit significantly influenced the growth and development of the aboveground components, including plant height, leaf area, and leaf greenness, during the early vegetative phase of this study. ...
Rapid climate change may put future food security under threat, which emphasizes the significance of assessing the morpho-physiological and biochemical traits associated with maize tolerance against recurrent water stress at the early vegetative stage. Three maize varieties (V1, SUWAN2301; V2, SUWAN4452; and V3, S7328) and three water levels (I1, daily watering as the control; I2, watering every two days as the short stress; and I3, watering every four days as the prolonged stress) were employed in a factorial design pot experiment. During the experiment, I1’s soil moisture content (SMC) was maintained at almost 100% of its field capacity (FC), whereas I2 and I3’s volumetric SMC dropped to an average of 22.10% and 11.57%, respectively, following a stress phase. Fourteen distinct characteristics of maize were investigated at 5, 9, and 13 days after watering treatment initiation (DAWTI). The findings revealed that water levels significantly influenced all the tested traits (p < 0.05), except for a few traits at 5 or 9 DAWTI only, whereas the maize variety significantly influenced most of the studied attributes (p < 0.05). Except for proline content in leaf (PrL) and root (PrR); total soluble sugar in leaf (TSSL) and root (TSSR); and root length to shoot length ratio (RL:SL), the value of all analyzed characters was higher under I1 compared to I2 and I3. However, during the first recovery period (RP), the recovery rate (RR) of stem perimeter (SP), root length (RL), root dry weight (RDW), leaf water potential (LWP), leaf greenness (LG), and TSSL were higher in I2, whereas leaf area (LA) and RL:SL was higher in I3. However, in the second RP, the RR of plant height (PH), SP, RL, LWP, LG, and TSSL were higher in I3, whereas LA, RDW, RL:SL, PrL, PrR, and TSSR were higher in I2 compared to each other. Under I3, the RR of biochemical traits, i.e., PrL (29.45%) and TSSR (20.23%), were higher in the first RP, and PrR (20.74%) and TSSL (15.22%) were higher in the second RP. However, the variety V1 could recover more after a re-watering, and, in the second RP, it performed better in the case of LA (120.14%), PH (18.41%), SP (19.94%), RL (17.74%), Shoot dry weight (SDW) (56.82%), RDW (11.97%), LG (0.05%), PrR (42.55%), TSSL (18.54%), and TSSR (22.87%) than other varieties. The maize varieties performed differently under I1 and I3 according to the principal component analysis and stress tolerance index. The variety V1 exhibited superior performance under both water levels. The biplot analysis highlighted the importance of traits, such as PrL, RL, TSSL, TSSR, PrR, and RL:SL, in water-stressed conditions. However, re-watering following a water stress period triggered the recovery rates in most traits, particularly after the second four-day stress period, and variety V1 performed better as well. Nonetheless, more research on a genomic and molecular level is required to gain a deeper understanding of the precise processes of drought tolerance in maize, particularly under recurring water stress circumstances.
... Adequate moisture availability is necessary for optimum leaf development, maintenance of leaf greenness, assimilate production and partitioning as well as total dry matter yield. Water stress has adverse or deleterious effects on crops; the impact however depends on the severity of the water shortage and the developmental stage of the crop under stress (Chaves et al., 2002;Jaleel et al., 2008). Water stress has been reported to affect the meristematic processes during the initial phase of plant growth and establishment which, consequently, impaired plant growth, as a result of reduction in cell turgidity required for mitotic cell division, elongation and enlargement (Anjum et al., 2003;Bhatt and Srinivasa Rao, 2005;Jaleel et al., 2008). ...
... Water stress has adverse or deleterious effects on crops; the impact however depends on the severity of the water shortage and the developmental stage of the crop under stress (Chaves et al., 2002;Jaleel et al., 2008). Water stress has been reported to affect the meristematic processes during the initial phase of plant growth and establishment which, consequently, impaired plant growth, as a result of reduction in cell turgidity required for mitotic cell division, elongation and enlargement (Anjum et al., 2003;Bhatt and Srinivasa Rao, 2005;Jaleel et al., 2008). Studies are needed to increase the efficiency in the use of available water through appropriate water management options such as regulated irrigation which is one among many practices that is fast gaining ground, and appears a very promising option to achieving the goal of more crops per drop of water if properly adopted (Oiganji et al., 2010). ...
The study was conducted to evaluate the performance of two small scale irrigation schemes at north Wollo zone,
Amhara regional state using process and comparative performance indicators. The irrigation schemes were Golina
and Kokono with command area of 400ha and 80ha respectively. Primary data collection includes measuring
discharge at diversion weir, soil moisture before and after irrigation and depth of water applied. The secondary data
collection includes determination of crop types, total yields, farm gate prices of irrigated crops, area irrigated per
crop per season, and cost of production. The two schemes were compared using minimum sets of comparative
performance indicators which include agricultural, water use and physical performance indicators. The process
indicators (conveyance, application and storage) were used to check the performance of the two schemes. From the
analyses of the internal performance indicators, the conveyance, application, storage and overall efficiencies were
found to be 76.58%, 52.51%, 48.38% and 40.21% for Golina scheme and 38.02%, 65.93%, 44.89% and 25.07% for
Kokono scheme respectively. From the analysis of comparative indicators, the outputs per cropped area were found
as 1111.67 and 753.38 us
ha-1, the output per unit irrigation supply of 0.11 and 0.1us m-3
for Golina and Kokono respectively. The water use performances of the two schemes were compared, RWS found to
be 1 at both schemes, and RIS was found as 4 and 1.7 at Golina and Kokono. The irrigation ratio of Golina was
found to be 0.974 and that of Kokono was 0.51. In general, based on the assessment carried out, the Golina scheme
performed better than the Kokono scheme.
... Adequate moisture availability is necessary for optimum leaf development, maintenance of leaf greenness, assimilate production and partitioning as well as total dry matter yield. Water stress has adverse or deleterious effects on crops; the impact however depends on the severity of the water shortage and the developmental stage of the crop under stress (Chaves et al., 2002;Jaleel et al., 2008). Water stress has been reported to affect the meristematic processes during the initial phase of plant growth and establishment which, consequently, impaired plant growth, as a result of reduction in cell turgidity required for mitotic cell division, elongation and enlargement (Anjum et al., 2003;Bhatt and Srinivasa Rao, 2005;Jaleel et al., 2008). ...
... Water stress has adverse or deleterious effects on crops; the impact however depends on the severity of the water shortage and the developmental stage of the crop under stress (Chaves et al., 2002;Jaleel et al., 2008). Water stress has been reported to affect the meristematic processes during the initial phase of plant growth and establishment which, consequently, impaired plant growth, as a result of reduction in cell turgidity required for mitotic cell division, elongation and enlargement (Anjum et al., 2003;Bhatt and Srinivasa Rao, 2005;Jaleel et al., 2008). Studies are needed to increase the efficiency in the use of available water through appropriate water management options such as regulated irrigation which is one among many practices that is fast gaining ground, and appears a very promising option to achieving the goal of more crops per drop of water if properly adopted (Oiganji et al., 2010). ...
... This stress triggers dramatic morphological, physiological, biochemical, and molecular changes in the plant. Thus, drought stress in plants is characterized by a decrease in water content, reduced leaf water potential, stomatal closure, loss of turgor, and a reduction in cell growth (Jaleel et al., 2008). Although wheat needs water at all growth stages, it is more critical during the tillering, jointing, and anthesis stages (Thapa et al., 2020), as water scarcity during these phases can result in delayed germination, tillering, booting, heading, anthesis, grain filling, and maturity (Camaille et al., 2021). ...
... These studies offer profound insights, contributing to the scientific discourse on the interplay between forest drought dynamics and WUE. Jaleel et al. (2008) investigated the complex inter-relationship between forest drought and WUE of Catharanthus roseus. This research examines the WUE of two varieties, rosea and alba, subjected to divergent watering regimes. ...
This study investigates precipitation trends and drought dynamics in Moist Deciduous Forests (MDF) and Dry Deciduous Forests (DDF) over twenty years (2001–2020), with a focus on water use efficiency (WUE). Utilizing the Mann–Kendall test (MK-test), seasonal precipitation trends were analyzed, revealing nuanced patterns across forest types and seasons. The standardized precipitation index (SPI) approach was adopted to identify drought and non-drought/normal conditions. Additionally, MODIS-derived WUE dynamics were scrutinized during drought and non-drought periods to understand ecosystem responses to hydrological challenges. CHIRPS precipitation data was employed for seasonal Mann–Kendall (MK) tests, uncovering distinct trends and identification of drought and non-drought periods in MDF and DDF. The results indicate a decreasing trend in precipitation from January to May in MDF, while DDF shows no significant trend over the twenty years. The drought period (July–December of 2002) and (June-December of 2008) and the non-drought period (July–December of 2012) and (June–December of 2012) were identified for MDF and DDF, respectively. Analysis of WUE during these periods revealed resilient and resistant forest types. This study highlights the importance of understanding ecosystem responses to hydrological variability for informed forest management and conservation. The findings underline that MDF and DDF exhibit different responses to drought periods, reflecting their unique ecological attributes and environmental contexts. MDF demonstrates resilience to drought, with decreasing precipitation trends and sustained WUE during dry periods, while DDF displays resistance, characterized by reduced evapotranspiration rates and increased WUE. These empirical insights emphasize the need to comprehend diverse responses and adaptations within forest ecosystems to develop effective management and conservation strategies in the face of evolving climatic dynamics.
... Furthermore, waterdeficit stress also affects reactive oxygen metabolism in Catharanthus roseus. Jaleel et al. (2008) analyzed the changes in the reactive oxygen metabolism of Catharanthus roseus (L.) plants for H2O2 content, lipid peroxidation, and the free radical quenching systems (nonenzymatic and enzymatic antioxidants) under water (drought) stress and concluded that the water-deficit areas may be used for the cultivation of medicinal plants like C. roseus, and the economically important alkaloid production can be enhanced. The important thing is that, according to some studies it has been found that the protective effect of volatile isoprenoids can be particularly relevant under drought when stomata close, resulted in elevated leaf temperatures due to reduced transpiratory cooling of leaves. ...
Coriander (Coriandrum sativum L.) is used as an aromatic and medicinal vegetable. Plant growth regulators improve plant performance under unfavorable conditions. In this study, the interaction effects of 24-epibrassinolide (0, 0.5 and 1 µM) and three levels of drought stress (-2,-3.5 and-4.5 bars) were investigated on growth parameters and coriander leaves essential oil. The highest main stem length, diameter, shoot fresh weight, and shoot dry weight were obtained by 0.5 µM of 24-epibrassinolide (EBR) under-3.5 bar. Both 0.5 and 1 µM concentrations of 24-epibrassinolide protected leaves of chlorophyll a and b against the effects of water deficit. The plants under-3.5 and-4.5 bar water deficits showed more leaf electrolyte leakage compared to the control (-2 bar). The highest percentage of all six measured essential oil components (linalool, (e)-2-decenal, 2-hexa-decenal, carvone, α-pinene and (E)-2-dodecenal) were obtained under moderate and severe levels of regulated water deficit. Foliar spray of EBR 0.5µM under severe drought stress with-4.5 bar of matric potential increased the main essential oil compositions such as linalool, (E)-2-decenal and (E)-2-hexa-decenal.
... Total chlorophyll a, chlorophyll b, and carotenoids levels of wheat tissue were significantly reduced under salt stress conditions (Figure 1). The disorder of thylakoid membranes leads to the biosynthesis of proteolytic enzymes like chlorophyllase, causing chlorophyll degradation, damaging photosynthetic apparatus in plants (Rong-Hua et al., 2006), slowing down photosynthetic rate (Mafakheri et al., 2009), and hindering aggregated ions (Jaleel et al., 2008), thus leading to decreases in chlorophyll contents. Abd El-Hameid and Sadak (2020) and Sadak (2022) found that different photosynthetic pigment contents of sunflower and white termis plants were decreased under salinity stress levels. ...
... According to Ashraf and Foolad (2007) glycine betaine and proline by applying osmotic adjustment, reduce the negative effects of stress in the incidence of drought conditions. An increased root growth due to water stress was reported in sunflower (Tahir et al.,2002) and Catharanthus roseus ( Jaleel et al.,2008). A reduced acid invertase activity can arrest the development of reproductive tissues due to improper phloem unloading (Goetz et al., 2001). ...
Introduction Agricultural water deficit arises from both insufficient rainfall and soil water during the growing season to sustain a high crop yield. Projections show an increase in intense rain events and at the same time reduction in the number of rain days that leads to increased risk of drought as well as flood. Therefore, under rain fed conditions water scarcity is one of the most widespread limitations to crop production. Tendency of plants to keep up a high potential of water in the tissues under drought is called dehydration avoidance and tolerance that determines plant predisposition to survive from water deficiency is called drought resistance. Drought stress or low water stress has threefold effect on the plant reducing water potential, causing ionic imbalance and disturbing availability of nutrient ions. Terms like physiological unavailability of water or physiological drought are used when the plants become unable to the water from the soil due to its increased osmotic potential, although water may physically be present in sufficient quantities. Such alteration in water status leads to loss of turgor pressure, closure of stomata, significance reductions in transpiration, photosynthesis, protein synthesis and lipid metabolism. The energy requirements are increased due to more utilization in osmo-regulation to save the plants from stress damage.
... Qurg'oqchilik o'simliklarning o'sishi, hosildorligi, suv munosabatlari, membrananing yaxlitligi, pigment tarkibi va fotosintezga ta'sir qiluvchi asosiy omildir [47]. Agar qurg'oqchilik omili juda yuqori bo'lsa, o'simliklar fotosintez va metabolizmni to'xtatadi va natijada o'simlik nobud bo'ladi [24]. Qurgʻoqchilikning qishloq xoʻjaligi tuproqlariga salbiy taʼsiri tuproqning degradatsiyasiga, biologik xilma-xillikning yoʻqolishiga va qishloq xoʻjaligi hosildorligining pasayishiga, yer usti va yer osti suvlari sathining pasayishiga olib keladi. ...
This article discusses the causes and types of droughts, their effects on soil fertility, and how to prevent the
negative effects of drought stress on soil fertility. In particular, the importance of efficient land management in increasing
agricultural productivity and improving land tenure is emphasized, especially as demand for food increases due to
population growth. The article recognizes obvious changes in the natural environment and climate, as well as the annual
decrease in water resources in agriculture, which leads to soil and land drought. In the next 5-10 years, drought will have
a serious impact on soil fertility in Uzbekistan and around the world, harm the way of life of millions of people, destroy
ecosystems, and have a major impact on the productivity and quality of agricultural crops. Of great concern are the
expansion of areas affected by drought, decrease in soil fertility, and deterioration of soil properties. Drought is linked to
climate change and affects hydrology, meteorology, ecology and society. This article, based on Scopus science,
examines the extent to which droughts will intensify and their negative impacts on soil conditions over the next 20 years.
This article reviews sources aimed at elucidating the scientific basis for the application and impact of innovative methods
for mitigating drought stress and improving soil fertility
... Water stress curtails plant growth by negatively influencing numerous biochemical and physiological responses, including osmoprotectant and ROS activities, photosynthesis, chlorophyll synthesis, and gas exchange parameters (Li et al. 2021;Jaleel et al. 2008;Akram et al. 2023). The arid-environment imparts negative impact on growth and Communicated by Gábor Kocsy. ...
The application of potassium silicate fertilizers in agricultural sector is emerging as an efficient strategy in managing the effects of water stress on various crops. The current research investigates the protective role of silicon forms, namely kaolin (Al4Si4O10 (OH)8) and potassium silicate (K2SiO3) in alleviating the harmful impacts of water-deficit stress on maize. There are not sufficient reports on the protective role of these two silicon forms in alleviating water stress in maize. Maize genotypes: R-2315 (tolerant) and R-2317 (susceptible) were grown in plastic pots and water stress (60% field capacity) was applied at silking stage for 7 days. After imposition of water stress, 4% kaolin and 0.06% K2SiO3 was sprayed on plants. After 14 days of application of kaolin and K2SiO3, samples were collected. Under water stress, the treatment of kaolin and K2SiO3 significantly (p ≤ 0.001) enhanced the shoot length, root length, shoot fresh weight, root fresh weight, shoot dry weight, root dry weight, in both maize genotypes (R-2315 and R-2317). Furthermore, applications of kaolin and K2SiO3 significantly improved stomatal conductance (gs), rate of photosynthesis (A), transpiration rate (E), and relative water contents (RWC) under applied water stress. Treatments of kaolin and K2SiO3 also showed a significant decrease in oxidative stress parameters like malondialdehyde, relative membrane permeability and hydrogen peroxide (H2O2) contents by increasing activities of enzymatic antioxidants such as peroxidase, catalase and superoxide dismutase, non-enzymatic antioxidant (anthocyanins, flavonoids, ascorbic acid), and osmolytes (proline, total free amino acids, total soluble proteins, anthocyanin), under water deficit stress. Conclusively, among treatments and genotypes, application of K2SiO3 and R-2315 showed maximum improvement in growth, morphological and biochemical attributes under water stress. These findings demonstrated that kaolin and K2SiO3 foliar application could be adapted as an effective strategy to control the negative impacts of water stress in crops.
... Drought is a multidimensional stress factor affecting plants at various levels (Zhang, Zhu, et al., 2022). Water deficiency disrupts critical metabolic functions, ultimately leading to plant death (Jaleel et al., 2008). Thus, retaining more water and maintaining a higher relative water content (RWC) and preventing water loss during water deficiency is crucial for drought survival. ...
MicroRNA169 (miR169) has been implicated in multi‐stress regulation in annual species such as Arabidopsis, maize and rice. However, there is a lack of experimental functional and mechanistic studies of miR169 in plants, especially in perennial species, and its impact on plant growth and development remains unexplored. Creeping bentgrass (Agrostis stolonifera L.) is a C3 cool‐season perennial turfgrass of significant environmental and economic importance. In this study, we generated both miR169 overexpression and knockdown transgenic creeping bentgrass lines. We found that miR169 acts as a positive regulator in abiotic stress responses but is negatively associated with plant growth and development, playing multiple critical roles in the growth and environmental adaptation of creeping bentgrass. These roles include differentiated spatial hormone accumulation patterns associated with growth and stress accommodation, elevated antioxidant activity that alleviates oxidative damage induced by stress, ion‐channelling membrane components for maintaining homeostasis under saline conditions, and potential cross‐talks with stress‐regulating transcription factors such as AsHsfA and AsWRKYs. Our results unravel the role of miR169 in modulating plant development and stress responses in perennial grass species. This underlines the potential of manipulating miR169 to generate crop cultivars with desirable traits to meet diverse agricultural demands.
... No significant differences were recorded between them, with an rise rate of 68.28% and 73.49%, respectively, with comparing to the non-irrigation treatment, which recorded the lowest average for this property, amounting to 0.447. The rise in absorbing water in the male flowering stage and the irrigation cutting in the milky stage can be related to the accumulation of low-molecularweight soluble substances inside the cells such as proline and soluble sugars, Because the cells' buildup of small-molecularweight molecules keeps the swelling pressure in check, regular intracellular metabolic processes can continue even when the water level is low (Bodner et al., 2015 ), as plants adapt to water stress by increasing the capacity to absorb water (Jaleel et al., 2008). Relative Water Content: The analysis of variance Table 7 and Table 4 illustrated significant difference between the averages of this trait for the two cultivated varieties. ...
A study in the real world with a Randomised Complete Block Design (R.C.B.D.) utilising a split-split diagrams layout with three separate replicates was carried out at the research facility of the college's water resources and soil sciences department at the Agriculture faculty / University of Diyala in the autumn season 2022. The experiment included three stages of cutting off irrigation: male flowering, milky stage, and three concentration levels of Citrullus Colocoynthis extract. Two cultivars of Zea mays L. were used: AGN720 and JAMESON. The concentration levels were 50 ml L-1 and 100 ml L-1, respectively, and two cultivars were used: AGN720 and JAMESON Citrullus Colocoynthis extract has an anti-transpiration effect on the water balance of leaves and water use efficacy of Zea mays L. grown under water stress conditions. The most important results are as follows: the AGN720 variety recorded the best water use efficiency, with an increase of 9.04% compared to the JAMESON variety. Spraying the extract of Citrullus Colocoynthis as anti-transpiration at a concentrate level of 100 ml L-1 increased the capability of water retention, relative water content, and water use efficiency. The irrigation cut-off treatment in the milky phase stage had the best water use efficiency, saving 2.559 kg of grain m-3 water compared to the no-cut irrigation treatment.
... According to Qaderi et al. (2007), drought stress may cause stunted growth as a result of decreased cell wall flexibility and turgor, changes in plant architecture that result in decreased height, smaller leaves, fewer leaves, decreased leaf water potential, turgor pressure, stomatal closure, and reduced cell growth and expansion. Other crucial physiological mechanisms, including the production of chlorophyll, photosynthesis, respiration, nutrition, and carbohydrate metabolism, are all impacted by drought stress (Jaleel et al., 2008;Farooq et al., 2009;Li et al., 2011). Overall, these findings highlight the sensitivity of plant growth to environmental factors, particularly light quality, and quantity, as well as the impact of PEG treatment. ...
Spinach (Spinacia oleracea L.) is a highly valuable leafy vegetable, abundant in vitamins, minerals, and antioxidants, offering various health benefits such as enhancing cardiovascular health, reducing inflammation, and aiding digestion. Consequently, it is crucial to effectively cultivate and maintain spinach's quality. Light plays a pivotal role in the growth and development of plants, including spinach, where different light qualities can influence its morpho-physiological traits and overall quality. To explore this, an experiment was conducted, using three distinct LED lighting sets for spinach cultivation. Light 1 emphasized blue light, Light 2 served as the standard white light control, and Light 3 focused more on red light with occasional brief UV-C flashes. Additionally, mild water deprivation was induced using 2.5% polyethylene glycol (PEG). The results revealed that using a high red-to-blue light ratio with intermittent UV-C radiation significantly reduced various growth parameters of spinach, such as root length, shoot length, root volume, fresh and dry root and shoot weight, as well as total and relative chlorophyll contents, when compared to the control group. Furthermore, water deprivation had a negative impact on spinach's growth, affecting shoot and root length, and fresh and dry weight in all light qualities, proving to be fatal under Light 3 conditions. Therefore, it is essential to carefully select appropriate light qualities throughout the plant's life cycle to enhance the quality of spinach, especially when mild water deprivation is involved. Opting for a higher blue-to-red light ratio was found to be somewhat beneficial in improving the overall quality of spinach.
... According to Qaderi et al. (2007), drought stress may cause stunted growth as a result of decreased cell wall flexibility and turgor, changes in plant architecture that result in decreased height, smaller leaves, fewer leaves, decreased leaf water potential, turgor pressure, stomatal closure, and reduced cell growth and expansion. Other crucial physiological mechanisms, including the production of chlorophyll, photosynthesis, respiration, nutrition, and carbohydrate metabolism, are all impacted by drought stress (Jaleel et al., 2008;Farooq et al., 2009;Li et al., 2011). Overall, these findings highlight the sensitivity of plant growth to environmental factors, particularly light quality, and quantity, as well as the impact of PEG treatment. ...
Spinach (Spinacia oleracea L.) is a highly valuable leafy vegetable, abundant in vitamins, minerals, and antioxidants, offering various health benefits such as enhancing cardiovascular health, reducing inflammation, and aiding digestion. Consequently, it is crucial to effectively cultivate and maintain spinach's quality. Light plays a pivotal role in the growth and development of plants, including spinach, where different light qualities can influence its morpho-physiological traits and overall quality. To explore this, an experiment was conducted, using three distinct LED lighting sets for spinach cultivation. Light 1 emphasized blue light, Light 2 served as the standard white light control, and Light 3 focused more on red light with occasional brief UV-C flashes. Additionally, mild water deprivation was induced using 2.5% polyethylene glycol (PEG). The results revealed that using a high red-to-blue light ratio with intermittent UV-C radiation significantly reduced various growth parameters of spinach, such as root length, shoot length, root volume, fresh and dry root and shoot weight, as well as total and relative chlorophyll contents, when compared to the control group. Furthermore, water deprivation had a negative impact on spinach's growth, affecting shoot and root length, and fresh and dry weight in all light qualities, proving to be fatal under Light 3 conditions. Therefore, it is essential to carefully select appropriate light qualities throughout the plant's life cycle to enhance the quality of spinach, especially when mild water deprivation is involved. Opting for a higher blue-to-red light ratio was found to be somewhat beneficial in improving the overall quality of spinach.
... Chlorophyll contents in the leaves of quinoa plants were considerably reduced under water deficit conditions. This decline in chlorophyll contents under moisture deficit situations could be due to the inefficiency of the thylakoid membrane, with higher deprivation as compared to the production of chlorophyll contents through the synthesis of proteolytic enzymes, diminishing the process of photosynthesis and obstructing the accumulation of ions (Jaleel et al., 2008;Mafakheri et al., 2009). However, exogenously applied MLE30 significantly improved the leaves chlorophyll contents in quinoa plants. ...
... An extensive deep root system is advantageous to uptake water from deeper layers. Water stress in Catharanthus roseus has been observed to cause an increase in root development (Jaleel et al. 2008). However, in maize, water stress did not significantly decrease root development (Sacks et al. 1997). ...
The environmental stresses have no boundaries and without any warnings they hamper the plant biomass output and quality. Among these stresses, drought and salinity stress were the most significant in reducing the plant productivity. Nevertheless, because of its cumulative, subtle effects, and multifaceted nature, it negatively affects the morphological, physiological, biochemical, and molecular characteristics of plants and renders their ability to synthesize oxygen. In order to adapt to stress, plants have evolved a variety of intricate defense and adaptation mechanisms, including biochemical and physiological responses that vary depending on the species. We briefly highlight the complex adaption mechanisms and regularity network that enhance plant water stress tolerance and adaptability. The strategies used by plants under drought and saline conditions include modifications in growth pattern and structural dynamics, reduction of transpiration loss through changing stomatal conductivity, leaf rolling, root elongation, accumulation of compatible solutes, and enhancing the efficiency of transpiration, homeostatic balance between osmolytes, and delayed senescence. Approaches that are made to alleviate the stress include exogenous application of potassium, secondary metabolites, and osmoprotectants. Advanced omics technologies include trans-genomics and metabolomics were performed to increase stress tolerance. Besides nanoparticles utilization that control antioxidant enzyme activity for stress adaption in plants, improving plant tolerance by restoration of cell homeostasis, and mitigating the negative impacts of water stress are very promising for agriculture.
... Water stress is one of the major causes for crop loss worldwide, reducing average yields by 50% and over [5]. Water stress reduces plant growth by affecting various physiological and biochemical processes, such as photosynthesis, respiration, translocation, ion uptake, carbohydrates, nutrient metabolism and growth promoters [6]. ...
A field experiment was conducted at the Research and Production Station of the National Research Center in Nubaria District, Beheira Governorate, Egypt, during the 2020 /2021 to study the effect of organic (Poultry Manure) and inorganic fertilizers (Potassium Nitrate) on sunflower growth parameters under water stress conditions. The soil application of Poultry manure (0, 2, 4, 6 ton fed-1) occupied the main plots and potassium nitrate treatments applied as a foliar spray at the rates (0, 1, 2 and 3%) randomly distributed in the sub-plots. Results showed that the increase in poultry manure rates was accompanied by significant increase in chlorophyll content, relative water content and total leaf Area. Data indicated that the maximum values of the proline content were registered for the control treatment and the minimum values recorded with the application of 6-ton poultry manure fed-1 combined with 3.0% KNO3 foliar spray under sufficient and deficit irrigation treatments. Results indicated that increasing poultry manure rates was associated with significant increase of sunflower plant height, head weight, head diameter, 100 seed weight and grain yield of sunflower. Results indicated that the highest values of growth and yield parameters of sunflower were attained by application of 6.0 ton fed-1 poultry manure with a foliar spray KNO3 at a rate of 3.0% under water stress condition.
... For example, reduced leaf water potential, stomatal closure, reduced cell growth and enlargement are some effects of drought stress on crops [5]. The impairment of various physiological and biochemical functions, such as photosynthesis, respiration, nutrient metabolism, carbohydrate metabolism, chlorophyll synthesis, ion uptake and translocation, can reduce plant growth [5][6][7][8]. The area is characterized by lower soil quality than fertile lowlands, and the soil type can be classified as dystric cambisol. ...
To investigate the different responses of crops to drought stress under field conditions of Central European Climate for selected crop rotations, a field experiment was conducted at a test site in the Czech Republic from 2014 to 2021. Depending on the crop, rainout shelters were placed in late spring and early summer to study the effects of drought in the final stages of crop development. Due to these rainout shelters and the associated lower water availability for the crops during the summer, a reduction in leaf area index, biomass and yield was observed. For example, a yield decrease of more than 30% was observed for spring barley, winter rape and winter wheat compared to conditions without rainout shelters. The reduction was 25% and 18% for winter rye and silage maize, respectively, under rainout shelters. Soil moisture played a significant role in yield, where a predictive model based on monthly soil moisture explained up to 79% (winter rape) of the yield variance.
... Elevated temperatures and frequent episodes of drought driven by climate change affect developmental and physiological processes in plants, and ultimately crop yield and quality [2]. Drought stress also inhibits the growth of plants by influencing their various biochemical functions such as photosynthesis, chlorophyll synthesis, nutrient metabolism, ion uptake and translocation, respiration, and carbohydrate metabolism [3,4]. Moreover, it affects pollen development by disturbing the internal homeostasis of plant cells, possibly by altering the intracellular levels of sugars, hormones, and reactive oxygen species [5,6]. ...
Drought stress inducing pollen sterility can reduce crop yield worldwide. The regulatory crosstalk associated with the effects of drought on pollen formation at the cellular level has not been explored in detail so far. In this study, we performed morphological and cytoembryological analysis of anther perturbations and examined pollen development in two spring barley genotypes that differ in earliness and drought tolerance. The Syrian breeding line CamB (drought-tolerant) and the European cultivar Lubuski (drought-sensitive) were used as experimental materials to analyze the drought-induced changes in yield performance, chlorophyll fluorescence kinetics, the pollen grain micromorphology and ultrastructure during critical stages of plant development. In addition, fluctuations in HvGAMYB expression were studied, as this transcription factor is closely associated with the development of the anther. In the experiments, the studied plants were affected by drought, as was confirmed by the analyses of yield performance and chlorophyll fluorescence kinetics. However, contrary to our expectations, the pollen development of plants grown under specific conditions was not severely affected. The results also suggest that growth modification, as well as the perturbation in light distribution, can affect the HvGAMYB expression. This study demonstrated that the duration of the vegetation period can influence plant drought responses and, as a consequence, the processes associated with pollen development as every growth modification changes the dynamics of drought effects as well as the duration of plant exposition to drought.
... Non Commercial Use place (Jaleel et al., 2008). The consequences of imminent climate change, drought will have an intense impact on crop productivity in the future (Shanker et al., 2014). ...
... 33 To ameliorate the deteriorating effects of drought, antioxidants, such as CAT, POD, and SOD are upregulated, primarily to scavenge ROS. 46 The enzymatic activities of antioxidants was found considerably higher in plants treated with SA or HA + SA ( Figure 3). SA induced increase in activities of these antioxidants might be due to the fact that SA foliar application provides extra protection to the membranes of the plants subjected to water deficiency. ...
Background
Humic acid (HA) is an organic acid that is naturally present in soil organic matter and improves nutrient availability and the mechanisms involved in plant growth and development. Likewise, salicylic acid (SA) is an important plant hormone involved in the regulation of plant growth and development. A pot experiment was carried out to determine the effects of individual or combined HA and SA application on growth and yield of maize (Zea mays L.) under drought stress conditions. Two maize hybrids, namely, 30T60 (drought tolerant) and 75S75 (drought sensitive), were grown in semi‐controlled conditions and foliar applied with SA (1 mM), HA (100 mg L⁻¹) and their combination (HA + SA). The plants were exposed to drought stress at the tasseling stage (R1, 60 days after sowing) for 2 weeks, while control plants were given normal irrigation.
Results
The results showed that HA and SA applications significantly enhanced the gas exchange characteristics (photosynthetic rate, transpiration rate, and stomatal conductance), and antioxidant activity (catalase, guaiacol peroxidase, and superoxide dismutase) of water stressed maize plants. Foliar SA spray significantly increased the photosynthetic efficiency and activity of enzymatic antioxidants closely followed by HA + SA application that ultimately improved the yield and net benefit cost ratio of maize under water deficit conditions.
Conclusion
Our findings suggest that foliar spraying of SA at the initiation of the reproductive stage is a cost‐effective strategy to obtain a high maize yield under limited water conditions.
... Drought stress reduces turgor pressure, leaf water potential, and stomatal conductance in plants, resulting in decreased cell development and enlargement [8]. Drought stress also reduced chlorophyll content, photosynthesis, respiration, carbohydrate metabolism, nutrient uptake, and translocation [8,9]. Rice productivity will be reduced by 200-600 kg ha −1 due to variations in drought intensity and frequency (up to 20%) by 2050 [10]. ...
Rice (Oryza sativa L.) grain yield is reduced by drought stress during reproductive stages. In this work, the effects of foliar selenium (Se) spray on the reduction of drought stress are measured and the most critical stage of rice is identified. Three field experiments were carried out. In experiments I and II, the sensitive stage was determined by imposing drought stress at the panicle initiation and flowering stages by withholding irrigation for 10, 15, 20, and 25 days. In experiment III, drought stress was induced by depriving plants of moisture for 20 or 25 days. Se spray was then applied at rates of 0, 10, and 20 mg L⁻¹ to alleviate the drought, and its effects were evaluated. Overall, it was reported that the panicle initiation stage was more vulnerable to drought stress than the flowering stage, as evidenced by a larger reduction in grain yield. Employing Se as a foliar spray at a rate of 20 mg L⁻¹ under drought stress enhanced the number of filled grains m⁻², the total number of grains m⁻², and grain yield ha⁻¹ by 22.0, 4.3, and 11.0%, respectively, over water spray. This shows a positive interaction or synergistic interaction between drought tolerance and selenium application. These results demonstrate that foliage supplementation of Se at a dosage of 20 mg L⁻¹ alleviate the adverse effects of drought stress at the panicle initiation stage in rice cultivation. Se mitigated the negative effects of drought by improving the membrane stability index, relative water content, and proline content.
... The plant response towards stress depends on many factors such as, nature of plant species, developmental stage and severity as well as duration of stress (Denby & Gehring, 2005;Zhang et al., 2019;Saleem et al., 2020a). Limited water availability may destroy the cell structure and inhibit the activity of enzymes that ultimately leads towards the plant's demise (Jaleel et al., 2008). Water shortage in plants hinders the key processes of development; cell division and cell enlargement (Waraich et al., 2011). ...
... The upregulation of TIP1;1, TIP2;2, and PIP2;5 expression in phyA and phyB1B2 mutants indicates the enhancement of water transport in plants, even under water-deprivation conditions (Figure 5c). With respect to water uptake from the soil, the efficient use of water with better growth under conditions of finite water resources is considered a desired plant trait under drought conditions [67]. The level of water uptake was lower in phyA and phyB1B2 mutants (Figure 4d), indicating the regulation of water consumption and the enhancement of water use efficiency. ...
Drought stress is a severe environmental issue that threatens agriculture at a large scale. PHYTOCHROMES (PHYs) are important photoreceptors in plants that control plant growth and development and are involved in plant stress response. The aim of this study was to identify the role of PHYs in the tomato cv. ‘Moneymaker’ under drought conditions. The tomato genome contains five PHYs, among which mutant lines in tomato PHYA and PHYB (B1 and B2) were used. Compared to the WT, phyA and phyB1B2 mutants exhibited drought tolerance and showed inhibition of electrolyte leakage and malondialdehyde accumulation, indicating decreased membrane damage in the leaves. Both phy mutants also inhibited oxidative damage by enhancing the expression of reactive oxygen species (ROS) scavenger genes, inhibiting hydrogen peroxide (H2O2) accumulation, and enhancing the percentage of antioxidant activities via DPPH test. Moreover, expression levels of several aquaporins were significantly higher in phyA and phyB1B2, and the relative water content (RWC) in leaves was higher than the RWC in the WT under drought stress, suggesting the enhancement of hydration status in the phy mutants. Therefore, inhibition of oxidative damage in phyA and phyB1B2 mutants may mitigate the harmful effects of drought by preventing membrane damage and conserving the plant hydrostatus.
... Tis fnding agrees with the previous reports on wheat crops [114]. A signifcant reduction in the transpiration rate was also observed under drought stress conditions in crops such as wheat, rice, and maize [115,116]. ...
Red pepper (Capsicum annum L.) is an increasingly important economic crop in the world. Thus, this study aimed to investigate the growth, physiological, and biochemical responses of red pepper cultivars under drought stress conditions. A pot culture experiment was conducted in a completely randomized design with three replications, four treatments, and three cultivars. Totally, 36 pots and six seeds per pot were used to grow the seeds. After five weeks, the cultivars were exposed to different drought stress conditions (100% FC or control, 80% FC or low stress, 60% FC or moderate stress, and 40% FC or severe stress). All the collected data were subjected to an analysis of variance (ANOVA). Shoot length was reduced significantly ( p < 0.05 ) in the Hagerew cultivar under severe drought stress. The photosynthesis rate was reduced by 21.11% ( p < 0.05 ) in the Mitmita cultivar under severe drought stress. The highest percentage reduction of chlorophyll content (77.28%) was recorded in the Hagerew cultivar. Both Markofana and Mitmita responded to drought stress by increasing the accumulation of proline and phenolic compounds. The root-to-shoot ratio was increased significantly in both Markofana and Mitmita cultivars (27.91% and 50.92%), respectively, under drought-stress conditions. This study depicted that the cultivar Mitmita was the most drought-tolerant cultivar among the three cultivars.
... In water-deficit region, the upright roots of tree species seedlings are 10 times more in height than above-ground plant height (Larcher, 2003). Jaleel et al. (2008) reported that drought stress increased root length of Catharanthus roseus. Changes in the root system, such as size, density, length, propagation, development rate is considered as central strategy to face drought and to achieve tolerance (Tzortzakis et al., 2020). ...
This chapter explores the critical role of metabolite homeostasis in mitigating the adverse effects of abiotic stresses on plants. Abiotic stresses such as drought, salt, temperature, and heavy metal toxicity cause an excess of reactive oxygen species (ROS) and other cytotoxic chemicals, disturbing cellular balance. Plants counter these stresses by maintaining a dynamic equilibrium of ROS and antioxidants, with major enzymatic (e.g. superoxide dismutase, catalase, ascorbate peroxidase) and non-enzymatic (e.g. ascorbate, glutathione) components playing critical roles. While osmolytes including proline, glycine betaine, and trehalose aid in osmotic adjustment and maintain cellular structures, the glyoxalase system detoxifies methylglyoxal (MG). These defenses are mediated by transcription factors such as WRKY, NAC, MYB, bZIP, and AP2/ERF, which are part of genetic and epigenetic regulatory networks that govern synthesis, transport, and compartmentalization of essential metabolites. Gaining an understanding of these systems can help improve agricultural sustainability and crop development in the face of changing environmental conditions by revealing important information about plant resilience and adaptation.
Due to extended periods of below-normal rainfall and rising temperatures, drought is a significant global issue for agricultural productivity. Hydrological, agricultural, and meteorological droughts all pose different problems with regard to the availability of water for important crops, which in turn impacts plant development and yield. Depending on the crop species and stage of maturity, drought stress degrades plant metabolism and physiological processes, resulting in decreased growth and yield losses that can range from 30% to 90%. Acclimatization and adaptation are the two basic techniques that plants use to survive drought. Rapid alterations in physiological processes and chemical composition, including modifications to osmotic pressure, root and leaf size, and antioxidant systems, are all part of acclimatization. Xerophytism and succulence are two characteristics that drought-resistant plants have evolved to assist preserve cellular integrity and water balance in water-limited environments. Even with these tactics, the majority of important crops—such as maize, rice, and wheat—remain extremely vulnerable to drought stress. To lessen the effects of drought, researchers have looked into a number of strategies, including both conventional and cutting-edge methods. Conventional techniques, like the application of plant growth-promoting bacteria (PGPB) and morphological modifications, remain essential for improving drought resilience. Recent breakthroughs have provided innovative alternatives such as nanoparticle (NP) treatments and biochar, which enhance plant resilience. Biochar enhances soil moisture retention and nutrient accessibility, whereas nanoparticles augment water absorption and bolster molecular resilience under stress. Furthermore, microbial inoculants such as plant growth-promoting bacteria (PGPB) enhance nutrient and water absorption, facilitating growth in arid conditions. This review examines the impacts of drought stress on three important staple crops, emphasizing both traditional and novel approaches to lessen the consequences of drought. We highlight how combining insights from ecology, biochemistry, molecular biology, and cutting-edge technologies like biochar and nanoparticles can boost agricultural production and plant resistance in water-scarce environments.
Water is the catalyst of life and plays a profound role in plant physiological processes ranging from photosynthesis to intermolecular interactions through a hydrophobic bond. Because of the alterations due to changing environmental conditions, the plants are continuously exposed to a lack of optimum water availability, leading to impaired growth and disturbance in water transport and uptake. Drought is a prominent environmental factor that triggers various plant processes from morphological, physiological, biochemical, and molecular. Plants portray an array of drought tolerance mechanisms; these responses differ based on the type of plant species and may involve the functions of various stress genes. Reduction in plant growth and productivity due to stomatal closure affects photosynthetic efficiency, altering membrane integrity and several enzymes involved in adenosine triphosphate synthesis. Plants exhibit a range of drought tolerance mechanisms and undergo several phenological, morphological, physiological, biochemical, and molecular adaptations at the cellular, subcellular and whole plant levels. Also, drought stress induces the production of reactive oxygen species at the cellular level and is strongly protected by the increase in the enzymatic and non-enzymatic antioxidative system. This chapter/ review provides a glimpse of the effects and tolerance strategies adapted by the plant under drought stress.
The transformation of natural ecosystems by urban development presents significant challenges for plant species, particularly those with medicinal properties. These plants, rich in bioactive compounds with therapeutic effects, have been integral to traditional healing practices and remain central to modern pharmacology. However, adapting medicinal plants to urban environments characterized by pollution, climate fluctuations, and habitat fragmentation is crucial for maintaining their medicinal efficacy. In response to urban stressors, medicinal plants undergo diverse biological adaptations spanning morphology, physiology, biochemistry, gene expression, and epigenetics. These adaptations enable them to thrive amidst urban challenges and ensure the preservation of their medicinal qualities. Understanding these adaptive mechanisms is vital for cultivating high-quality medicinal plants in urban settings. This chapter delves into the biological responses of medicinal plants to urbanization, shedding light on how these responses influence their therapeutic potential. Integrating ecological and biological perspectives contributes to developing sustainable urban plant practices and conserving medicinal plant biodiversity.
The Himalayan forests are vulnerable to climate change leading to disturb the current flow of critical ecosystem services to the dependent population. Present study attempts to evaluate the current vulnerability status of major forest types in Nagaland, India due to climate change along with identifying the hot spots for mitigating the vulnerability of the forests. Vulnerability of mixed moist deciduous, pine, wet hill and wet temperate forests were evaluated using the IPCC framework. Local Moran's I analysis, hot spot analysis and a histogram analysis of the vulnerability were made in QGIS. Field data such as Shannon-Wiener Index and Importance Value Index along with secondary data such as edaphic factors, vegetation factors and climatic variables were used for vulnerability analysis. Analysis results that mixed moist deciduous forests had the highest area in under high-high clusters, hot spots and was highly vulnerable. The result suggests that very dense or moderately dense forest cover were less vulnerable than low density forests in the region. The study provides baseline information along with identification of vulnerable hot spot forests for future climate change policy and management of resources at the division level. The study suggests strengthening the less dense forests along with increasing the biodiversity through suitable strategy for mitigating the vulnerability.
Global warming and resulting climate abnormalities put plants under abiotic stress, which can have an adverse effect on their survival and productivity. These stressors impact diverse aspects of plant morphology, physiology, and biochemistry, disrupting ion homeostasis, antioxidant defence mechanisms, synthesis of osmoprotectants, and phytohormones including abscisic acid, salicylic acid, ethylene, and jasmonic acid mediating defence responses against abiotic stresses. This leads to disturbed plant osmotic regulation, reduced ion toxicity, and reduced reactive oxygen species (ROS). Importantly, plants are not merely subjected to additive effects of abiotic stresses, but also to complex interactions between them. In addition to their common stress responses, plants exhibit unique responses to combined stresses. They activate stress-responsive genes and proteins and synthesise various phytohormones and metabolites to mitigate the damage caused by multiple stressors. It is crucial to understand the intricate interactions between different abiotic stresses in order to comprehensively understand their impact on plant morphology, physiology, and biochemistry. The insights gained from such studies will facilitate the development of strategies to boost plant resilience and productivity during climate change.
Study’s Excerpt/Novelty This study presents a novel screening of 107 groundnut genotypes for drought tolerance under controlled water-stress and non-stress conditions, providing a comprehensive evaluation of their morphological and physiological traits. Significant differences were identified, with genotypes ICGV-IS-07902, ICGX-5M-00017/5/P5/P2, and ICGV-IS-13978 emerging as the top performers in drought tolerance. These findings offer valuable baseline information for breeding programs aimed at enhancing groundnut production in drought-prone regions, suggesting specific genotypes for further development and potential variety release. Full Abstract The importance of leguminous crops such as groundnut cannot be overemphasized globally. Due to the increase in global warming, water scarcity threatens the environment, thereby affecting plant growth and metabolic activities in both semi-arid and arid zones of the world. Drought stress has severely hindered groundnut yield because pod yield and other growth characteristics have been severely affected. Therefore, mitigating this hindrance requires a conscious selection of suitable genotypes that could withstand drought threats to groundnut production. The study aimed to identify drought-tolerant genotypes suitable for the groundnut breeding program. One hundred and seven (107) groundnut genotypes were screened for drought tolerance during the 2018 dry season in a split-plot design under non-stress and water-stress conditions. The mean squares for the morphological and physiological traits showed a highly significant (P≤0.01) difference between the genotypes under water stress and combined conditions. The mean performance using the Rank Summation Index revealed ICGV-IS-07902 as the top-performing genotype, followed closely by ICGX-5M-00017/5/P5/P2 and ICGV-IS-13978 while RS006F4B1-45(B) was the least ranked under water stress condition. Based on the PCA ranking under water-stress conditions, genotypes ICGV-IS-13115, RS006F4B1-45®, ICGV-IS-07853, ICGV-IS-13989, and RS006F4B-534 were the top 5 drought tolerant while genotypes ICGV-IS-07828, 12CS-010, ICGV-IS-07809, RS006F4B1-45(B) and ICGV-IS-07904 were the least 5 drought susceptible. The genotypes ICGV-IS-13115, RS006F4B1-45®, ICGV-IS-07853, and ICGV-IS-13989 were observed to be better for drought tolerance with high pod yield. It is suggested that these genotypes could be recommended for further breeding and variety release adapted to drought conditions.
A field experiment was carried out during the 2021-2022
agricultural season in two locations (Agricultural Research Station in
Grdarash and ARD company in Gueer location) To study wheat
response to three factors, including three kinds of arable land that
previously cultivated with (Legume, Vegetable and Wheat crop) with
using two bread wheat cultivars Hawler 2 and Hawler 4 (H2 and H4),
and three seeding rates (120, 140, and 160 kg ha-1). The experiment
was carried out according to the randomized complete block design
and the system of factorial experiment within a split plot with three
replications. Arable lands occupied the main plots and two bread
wheat cultivars in sub-plot and seeding rates were distributed
randomly in sub-sub-plot within each of the arable lands and cultivars.
The results revealed that legume field recorded maximum value
for the most of studied traits in Grdarash location, such as number of
grains spike-1, above ground biomass, thousand grain weight, grain
yield, spike density, harvest index and Protein content (48.361 grains,
1482.2 kg ha-1, 40.051 g, 6269.4 kg ha-1, 5.137 grain cm-1, 42.973, and
12.555 %) respectively, besides that, vegetable field recorded the
highest value on some similar traits as legume field, identical (spike
length, number of grains spike-1, grain yield, spike density, and
harvest index ( 9.781 cm, 49.428 grains, 6088.9 kg ha-1, 5.076 grain
cm-1, and 42.978), but wheat field showed the highest alone on
number of spikes m-2 (600.39 spikes). Whereas, in Gueer location
legume field recorded maximum value alone on gluten content
(33.722 %), and wheat field recorded highest on plant height, above
ground biomass, number of grains spike-1, and grain yield (75.156 cm,
1328.0 kg ha-1, 53.233 grains and 4955.6 kg ha-1) respectively.
VII
As for the cultivars, Hawler 4 surpassed on Hawler 2 in more
the studied traits at both locations. So that, Hawler 4 gave it maximum
value on (plant height, spike length, thousand grain weight, harvest
index, gluten content, and hectoliter weight (91.340 cm, 9.784 cm,
38.803 g, 42.952, 35.703 %, and 0.802 kg L-1) respectively, in
Grdarash location.
On the other hand, in Gueer location Hawler 4 recorded the
highest value of (plant height, number of spikes m-2, spike length,
thousand grain weight, grain yield, harvest index) by recording
(82.207 cm, 353.85 spike, 9.940 cm, 42.250 g, 4829.6 kg ha-1, and
40.172) respectively, both Seeding rates (140 kg ha-1 and 160 kg ha-1)
was affected significantly on wheat traits. which 140 kg ha-1 gave it
highest value on harvest index by recording (42.155) and (above
ground biomass with number of spike-1) at 160 kg ha-1 gave it highest
value by recording (1475.8 kg ha-1, 534.06 spike) in Grdarash
location. but (160 kg ha-1) seeding rate in Gueer location recorded
maximum value on plant height, above ground biomass, number of
spikes m-2 and grain yield (75.656 cm, 1290.0 kg ha-1, 378.66 spikes
and 4852.8 kg ha-1).
Besides that, triple interaction in Grdarash location was
significant, grain yield was a significant effect in legume field with
both cultivars (Hawler 2 and Hawler 4) at 160 kg ha-1 recorded
maximum value (6783.3 and 6650.0 kg ha-1) although protein content
gave it maximum value in legume field with both cultivars at three
different seeding rates so, vegetable field with Hawler 2 and Hawler 4
at 140 kg ha-1 recorded highest value (12.366 and 12.400 %) but in
Gueer location interaction between three-factors on grain yield was
significant which recorded maximum in (legume field × Hawler 4 ×
160 kg ha-1) by (5483.3 kg ha-1) also, wheat field gave it highest value
VIII
with Hawler 4 at 140 kg ha-1 by (5466.7 kg ha-1), protein content
recorded highest value in (wheat field × Hawler 2 × 160 kg ha-1) by
12.766 %, gluten content recorded highest value in (legume field ×
Hawler 4 × 120 kg ha-1) by 35.000 % and with the same field and
cultivar at 160 kg ha-1 recorded maximum value (34.666 %).
In nature, plants are always subjected to various abiotic stresses such as drought, salinity, high temperatures and so on. Among these drought is a worldwide problem, responsible for limiting the growth, physiology and productivity of plants, thus has become a challenge for global food security towards growing population. Proso millet (Panicum miliaceum L.) belonging to family Poaceae grows under wide environmental conditions and different soil profile. In this view, an experiment was conducted to investigate the range of tolerance and change of metabolic activities of Proso millet under drought stress. The control plants were irrigated regularly and treated plants were irrigated at 3, 5, 7, day intervals up to 60day interval drought (DAS). The root and leaf samples were collected on 30 DAS, 45 DAS and 60 DAS respectively for morphological and biochemical analysis. It was found that with increasing duration of water deficit, tremendous increases of antioxidants activities were recorded at all growth stages compared to control on 7DID at 60DAS. Furthermore, a decreased rate of growth, biomass and chlorophyll content was recorded in treated plants than control. Therefore, it can be concluded that proso millet has affinity to survive under prolonged drought stress and can help to understand the mechanism of photosynthetic efficacy for improving crop productivity.
A major portion of maize is produced under rainfed conditions in the tropics with relatively poor yield because of the unpredictable and irregular distribution of seasonal rainfall, as well as a decline in pre-rainy season rainfall due to climate change, so identification of sustainable production options is utmost needed. Thus, the present studies were conducted in a greenhouse (GH) to ascertain the water stress-tolerant traits of maize and at the field level in the tropical environment of Thailand to see the stimulating possibility of the ascertained traits in a locally popular cultivar using ethephon. Depending on tolerance level, three maize genotypes (Suwan 2301 > Suwan 4452 > S 7328) were tested under different water conditions—well-watered, short-term, and long-term water stress—in the GH. At the field level, the locally popular maize cultivar Suwan 5819 was examined with six ethephon levels (doses in g a.i. ha⁻¹ of ethephon, i.e., T1, 281 at V6 stage; T2, 281 at V6 + 281 at V10 stage; T3, 281 at V10 stage; T4, 562 at V6 stage; T5, 562 at V6 + 562 at V10 stage; T6, 562 at V10 stage) against no ethephon application (T0) under rainfed conditions. Maize suffered from the scarcity of sufficient rainfall during 26–39 days after planting (DAP) and 43–63 DAP in the field. The yield index (YI) was identified from biplot analysis as one of the suitable standards for drought tolerance checks for maize at GH as well as at field level in the tropics. The YI value of observed agro-physio-biochemical traits of maize in GH showed that relative water content (RWC, 1.23), stem base diameter (SBD, 1.21), total soluble sugar (TSS, 1.15), proline (Pr, 1.13), aboveground plant biomass (APB, 1.13), root weight (RW, 1.13), relative growth rate (RGR, 1.15), specific leaf weight (SLW, 1.12), and net assimilation rate (NAR, 1.08) were the most desirable. Efforts were made to stimulate these traits under water stress at the field level. Ethephon application as T1 helped to gain higher kernel yield (KY) (5.26 t ha⁻¹) with the support of higher RWC (90.38%), proline (24.79 µmol g⁻¹ FW), TSS (1629 mg g⁻¹ FW), SBD (24.49 mm), APB (271.34 g plant⁻¹), SLW (51.71 g m⁻²), RGR (25.26 mg plant⁻¹ day⁻¹), and NAR (0.91 mg cm⁻² day⁻¹) compared to others, especially no ethephon application. Furthermore, the attributes SLW, SBD, Pr, heat utilization efficiency (HUE), 100-kernel weight, TSS, electrolyte leakage, and lodging percentage showed a substantial direct effect and significant correlation with KY. Aside from higher KY, ethephon application as T1 tactics resulted in higher values of energy efficiency (1.66), HUE (2.99 kg ha⁻¹ °C days⁻¹), gross margin (682.02 USD ha⁻¹), MBCR (3.32), and C absorption (6.19 t C ha⁻¹), indicating that this practice may be a good option for maize sustainable production under rainfed conditions.
Drought hampers global rice production. Abscisic acid (ABA) plays versatile roles under different environmental stresses. While the link between drought and ABA is known, its effect on ABA biosynthesis genes and metabolites is unclear. This study explored the impact of drought on various metabolites, namely beta‐carotene, zeaxanthin, antheraxanthin, violaxanthin, neoxanthin, and candidate genes viz. zeaxanthin epoxidase ( ZEP ) and 9‐ cis epoxycarotenoid dioxygenase ( NCED ) of ABA biosynthesis pathway in rice cultivars (N22 and IR64) at anthesis {65 DAT (Days after transplanting)} with different stress levels. In stressed plants, zeaxanthin significantly increased (92%), while the concentration of beta‐carotene, antheraxanthin, violaxanthin and neoxanthin decreased as drought stress progressed. The concentration of metabolites in roots was notably lower than in leaves in both genotypes. The ZEP expression was upregulated in roots (8.24‐fold) under drought stress. Among five NCED isoforms, NCED 3 showed significant upregulation (7.29‐fold) in leaf and root tissue. NCED 1 was significantly downregulated as stress progressed and was negatively correlated with ABA accumulation. NCED 2, NCED 4 and NCED 5 showed no significant change in their expression. Drying and rolling of rice leaves was observed after imparting drought stress. The findings revealed that drought stress significantly influenced the expression of candidate genes and the concentration of metabolites of the ABA biosynthesis pathway. There was a significantly higher accumulation of ABA in N22 leaves (47%) and roots (30%) compared to IR64. The N22, a drought‐tolerant genotype, exhibited significantly higher concentrations of intermediates and demonstrated increased expression of ZEP and NCED 3, potentially contributing to its resilience against drought.
Lipids are a principal component of plasma membrane, acting as a protective barrier between the cell and its surroundings. Abiotic stresses such as drought and temperature induce various lipid-dependent signaling responses, and the membrane lipids respond differently to environmental challenges. Recent studies have revealed that lipids serve as signal mediators forreducing stress responses in plant cells and activating defense systems. Signaling lipids, such as phosphatidic acid, phosphoinositides, sphingolipids, lysophospholipids, oxylipins, and N-acylethanolamines, are generated in response to stress. Membrane lipids are essential for maintaining the lamellar stack of chloroplasts and stabilizing chloroplast membranes under stress. However, the effects of lipid signaling targets in plants are not fully understood. This review focuses on the synthesis of various signaling lipids and their roles in abiotic stress tolerance responses, providing an essential perspective for further investigation into the interactions between plant lipids and abiotic stress.
Basmati rice is inherently sensitive to various environmental stresses. Abrupt changes in climatic patterns and freshwater scarcity are escalating the issues associated with premium-quality rice production. However, few screening studies have selected Basmati rice genotypes suitable for drought-prone areas. This study investigated 19 physio-morphological and growth responses of 15 Super Basmati (SB) introgressed recombinants (SBIRs) and their parents (SB and IR554190-04) under drought stress to elucidate drought-tolerance traits and identify promising lines. After two weeks of drought stress, several physiological and growth performance traits significantly varied between the SBIRs (p ≤ 0.05) and were less affected in the SBIRs and the donor (SB and IR554190-04) than SB. The total drought response indices (TDRI) identified three superior lines (SBIR-153-146-13, SBIR-127-105-12, SBIR-62-79-8) and three on par with the donor and drought-tolerant check (SBIR-17-21-3, SBIR-31-43-4, SBIR-103-98-10) in adapting to drought conditions. Another three lines (SBIR-48-56-5, SBIR-52-60-6, SBIR-58-60-7) had moderate drought tolerance, while six lines (SBIR-7-18-1, SBIR-16-21-2, SBIR-76-83-9, SBIR-118-104-11, SBIR-170-258-14, SBIR-175-369-15) had low drought tolerance. Furthermore, the tolerant lines exhibited mechanisms associated with improved shoot biomass maintenance under drought by adjusting resource allocation to roots and shoots. Hence, the identified tolerant lines could be used as potential donors in drought-tolerant rice breeding programs, administered for subsequent varietal development, and studied to identify the genes underlying drought tolerance. Moreover, this study improved our understanding of the physiological basis of drought tolerance in SBIRs.
Rice (Oryza sativa L.) is a major food crop which is widely consumed throughout the world, it consumes alarge amount of water during its life cycle. Regarding global climate change, it is turning into a more significant concern. One of the most severe restrictions in rice production is drought situation. In this situation rice is impeded in a number of ways, including decreased germination, plant height, biomass, tiller count, and another leaf and root traits, reduced photosynthesis, transpiration, stomatal conductance, water use efficiency, relative water content, chlorophyll content, photosystem II activity, membrane stability, carbon isotope discrimination, and abscisic acid content, as well as biochemical (accumulation of osmoprotectants like proline, sugars, polyamines, and antioxidants) and molecular (altered expression of genes encoding transcription factors and defence related proteins) levels, due to drought stress condition. Rice production is severely limited by drought stress, which causes significant monetary losses. It has become imperative to improve crop productivity on the drought-prone rainfed areas with a priority in light of the current and projected world food demand.
An array of organic compounds synthesized by plants for counteracting adverse environmental conditions and pathogens are called plant secondary metabolites. These phytochemicals are exclusive and impeccable sources of various high-demand, lifesaving, and commercially important pharmaceuticals. Elicitation is the significant approach of triggering physiological modifications and stimulating plant protection mechanisms by adding elicitors for the improved secretion of secondary metabolites. The effect of various biotic and abiotic elicitors on in vitro plant cultures and hairy root cultures for the increased accumulation of metabolites has been witnessed in majority of medicinal plants. Further, full exploration of research in this particular area will open up new horizons in secondary metabolite synthesis pathways and metabolomics. Here in this review, we focus on the mechanism and attributes of elicitation, types of elicitors, and its effect on plant secondary metabolite production.
An essential macronutrient for plants, calcium (Ca2+) is needed for a variety of functions both under normal and stressful situations. It displays characteristics of a structural component and acts as a secondary messenger during several physiological processes. It behaves as a signaling molecule while under stress. It manifests a variety of symptoms, such as weakening the cell wall, at lower concentrations or in insufficient situations, demonstrating its significant significance at peak levels. Calcium is taken up by roots through a variety of channels or proteins that are positioned on the plasma membrane. These channels are divided into three categories based on their electrophysiological properties: voltage-independent channels (VICs), hyperpolarization-activated channels (HACCs), and depolarization-activated channels (DACCs). Protein channels allow it to enter the cytosol, where it is then exported towards the apoplast or xylem by Ca2+/H+ antiporters or Ca2+-ATPases. In addition to these, Ca2+ also functions as a secondary messenger throughout physiological, stress-related, and developmental events. The interaction of pumps and influx exporters/channels, also known as calcium signatures, is what causes the signal to be produced. The primary decoding proteins for reactions are calmodulins (CaM), calmodulin-like proteins (CMLs), calcineurin B-like proteins (CBLs), CBL-interacting protein kinases (CIPKs), and calcium-dependent protein kinases (CDPKs/CPKs). After the signals have been processed, transporters, transcription factors, and channels then transmit them into outputs, which lead to the shutting of stomata and gene expression. Ca2+ homeostasis is also preserved during signaling by several transporting components that control the outflow and import of Ca2+, respectively. These transporters include Ca2+-ATPases, Ca2+/H+ exchangers, Mechanosensitive channels (MSLs), Cyclic nucleotide-gated channels (CNGCs), Two Pore Channels (TPCs), Glutamate-like Receptor channels (GLRs), and Ca2+/cation exchangers (CCXs). Due to their sessile nature, plants have been subjected to a range of environmental challenges, including nutrient deficit, metal stress, temperature stress and drought. To investigate the many roles that calcium plays, this review has gone into detail about the various processes via which Ca2+ has been studied to play a part throughout these stresses.
In the present investigation, ‘rosea’ and ‘alba’ varieties of Catharanthus roseus (L.) G. Don. seeds were grown with different concentrations (15, 30, 45 and 60 mM) of sodium chloride (NaCl), in order to study the effects of salinity on germination behaviour, seedling vigour (root and shoot length), lipid peroxidation (LPO) and proline metabolism. It was found that germination was delayed at lower salinity levels and inhibited at higher salinity regimes. NaCl treatment caused a serious decrease in the early seedling growth by means of reduced seedling vigour at higher salinity levels. The LPO was estimated as thiobarbituric acid reactive substances (TBARS) and found increased under salt stress. Glycine betaine (GB) and proline (PRO) contents significantly accumulated in both the varieties of seedlings under salt stress. Under NaCl stress, the activity of proline oxidase (PROX) decreased and the γ-glutamyl kinase (γ-GK) activity increased.
Potted plants of Asteriscus maritimus (L.) Less were submitted to water stress (during two consecutive cycles, irrigation water was withheld for 5 days followed by a recovery period of 25 days) and saline stress (150 days of exposure to 0, 70 and 140 mM NaCl daily irrigation) in order to assess the effect on leaf water relations and growth parameters. Plants under saline and water stress conditions showed lower biomass and an early reduction in leaf expansion growth. Both stresses promoted a substantial degree of stomatal regulation; but, in spite of this, the plants showed signs of leaf tissue dehydration, decreases in RWC and Ψpd values. However, salt-treated plants, developed a NaCl inclusion mechanisms, underwent osmotic adjustment, which was able to maintain leaf turgor. Under both stress conditions gl was independent to plant water status in the range between –0.8 and 1.0 MPa. Under water stress conditions, midday leaf water potential showed a threshold value (around −1.1 MPa), below which leaf conductance remained constant. In the salt-treated plants, the gradual closure of the stomata over a wide range of Ψmd may be important in maintaining some level of photosynthesis.
Groundnut (Arachis hypogea L.), is an important legume cash crop for the tropical farmers and its seeds contain high amounts of edible oil (43–55%) and protein (25–28%). Even though it is a fairly drought-tolerant, production fluctuates considerably as a result of rainfall variability. To develop a water stress response function in groundnut, research works have been done to improve the performance under varying degrees of stress at various physiological stages of crop growth. This review summarizes recent information on drought resistance characteristics of groundnut with a view toward developing appropriate genetic enhancement strategies for water-limited environments. It is suggested that there are considerable gains to be made in increasing yield and stabilizing the yield in environments characterized by terminal drought stress and by shortening crop duration. Many traits conferring dehydration avoidance and dehydration tolerance are available, but integrated traits, expressing at a high level of organization are suggested to be more useful in crop improvement programs. Possible genetic improvement strategies are outlined, ranging from empirical selection for yield in drought environments to a physiological–genetic approach. It was also suggested that in view of recent advances in understanding drought resistance mechanisms, the later strategy is becoming more feasible. It is summarized that application of knowledge into practice in a systematic manner can lead to significant gains in yield and yield stability of the worlds groundnuts production. Research is needed to develop transferable technology to help farmers of arid and semi-arid regions. Increasing soil moisture storage by soil profile management and nutrient management for quick recovery from drought are some of the areas that need to be explored further.
The effect of water stress on growth, Na+ and K+ accumulation and water utilization was investigated in plants of two populations of Atriplex halimus L. originating from Kairouan (Tunisia) and Tensift (Morocco). Water deficit was applied by withholding water for 22 days. All plants remained alive until the end of the treatment although growth was strongly reduced in both populations. Water stress decreased CO2 assimilation in saturating conditions, mainly in the population obtained from Kairouan, suggesting an impact of drought on the dark phase of photosynthesis, beside a decrease in stomatal conductance which was recorded mainly in the population obtained from Tensift. The two studied populations did not differ in their water consumption, as indicated by similar soil gravimetric water content and plant transpiration. However, water use efficiency increased under stress conditions in the population from Tensift but not in the population from Kairouan. Thelatter population displayed a larger capacity for osmotic adjustment. A drought-induced specific increase in Na+ concentration was also reported in both populations. It is concluded that in A. halimus, water stress resistance estimated in terms of biomass production, could be associated with higher WUE rather than with with a greater osmotic adjustment and that sodium may assume a specific physiological function in this xerohalophytic C4 species.
The effect of paclobutrazol, a plant growth regulator, on antioxidant defense system was investigated in Catharanthus roseus (L.) G. Don. plants subjected to NaCl stress. The growth parameters were significantly reduced under 80mM NaCl treatment;
however, this growth inhibition was less in paclobutrazol-treated (15mgl−1plant−1) plants. The non-enzymatic antioxidants ascorbic acid and reduced glutathione were affected under NaCl stress and they increased
significantly under paclobutrazol treatment when compared to NaCl treated as well as control plants (P≤0.05). The activity of antioxidant enzyme ascorbate peroxidase showed a significant enhancement under salinity stress.
The catalase activity decreased in roots of NaCl-treated plants, but recovered with paclobutrazol treatment. The results suggested
that paclobutrazol have significant role in contributing salt stress tolerance of C. roseus by improving the components of antioxidant defense system.
We exposed cuttings of two sympatric species of Sect. Tacamahaca Spach, Populus cathayana Rehder and Populus przewalskii Maximowicz, to two watering regimes in a greenhouse. In the semi-controlled environmental study, two watering treatments which were watered to 100 and 25% of field capacity were used, respectively. The effects of water deficit on early growth, biomass allocation and water use efficiency (WUE) were investigated. We found that there were significant interspecific differences in early growth, dry matter allocation and water use efficiency between two sympatric Populus species. Compared with P. cathayana, P. przewalskii showed higher shoot height, dry matter accumulation, number of leaves, total leaf area, fine root mass, fine root/total root ratio and water use efficiency under both well-watered and water-stressed treatments. On the other hand, P. przewalskii also showed higher root mass/foliage area ratio, root/shoot ratio and carbon isotope composition than P. cathayana under water-stressed treatment. The results suggested that there were different water-use strategies between two sympatric Populus species, P. przewalskii with higher drought tolerance may employ a conservative water-use strategy, whereas P. cathayana with lower drought tolerance may employ a prodigal water-use strategy. The findings confirm the existence of interspecific genetic differences in early growth, dry matter allocation and water use efficiency as affected by water stress, these variations in drought responses may be used as criteria for species selection and tree improvement.
The research was performed to define the effect of water deficit on early growth, biomass allocation and biochemical constituents, proline metabolism and yield of five varieties of bhendi (Abelmoschus esculentus (L.) Moench.) plants. We found that there were significant differences in early growth, dry matter accumulation, biochemical constituents and proline metabolism among the five varieties. The root length, shoot length, total leaf area, fresh weight and dry weight were significantly reduced under drought-induced stress treatment. The proline content and g-glutamyl kinase were significantly enhanced and proline oxidase activities were reduced. Drought stress caused an increase in the free amino acid and glycinebetaine content.
The sensitivities of rate of assimilation of CO2 and rate of transpiration of water vapour to change in stomatal aperture are examined. We suggest that stomatal aperture is adapted to equalise the marginal benefit of assimilation and the marginal cost of transpiration. We show how the temporal and spatial variation of stomatal aperture is determined by the variation in external environment and leaf internal physiological properties. We indicate how the increase in cost of transpiration relative to the benefit of assimilation may determine the decline in stomatal aperture with decrease in the amount of water available to the roots of a plant, even though the plant may suffer no immediate lesion due to shortage of water.
The interaction of plants through their influence on their common environment is examined. We show that rate of transpiration in communities may be much less sensitive to change in stomatal aperture than in the single plant. The implications of that are discussed.
AIM: To evaluate the antioxidant potential and indole alkaloid variations in different parts of two varieties (rosea and alba) of Catharanthus roseus. METHODS: The antioxidant potentials were examined in terms of non-enzymatic antioxidant molecules and activities of antioxidant enzymes. The non-enzymatic antioxidant molecules studied were ascorbic acid, α-tocopherol and reduced glutathione. The estimated antioxidant enzymes were superoxide dismutase, ascorbate peroxidase, catalase, peroxidase and polyphenol oxidase. The analyses were carried out in the field-collected samples. The antioxidant and alkaloid profiles were estimated from roots, stems, leaves, flowers and pods. RESULTS: The roots and stems had higher antioxidant content when compared with other parts of the plant. The lowest content was found in flowers and pods. The rosea variety was good performer in terms of antioxidant and alkaloid contents. The activities of antioxidant enzymes were higher in leaves when compared with other parts. But indole alkaloid content was found to be higher in the roots of rosea variety. CONCLUSION: The pink-flowered rosea variety of Catharanthus roseus is more suitable for cultivation in terms of antioxidant and alkaloid contents.
Glasshouse experiments at two developmental stages (tuber initiation and tuber bulking) of potatoes (Solanum tuberosum L.) were conducted to investigate plant water relation and leaf gas exchange characteristics during progressive soil drying. Leaf relative water content (RWC), leaf water potential (C l), root water potential (C r), stomatal conductance (g s), photosynthesis (A), and xylem sap abscisic acid (ABA) concentration ([ABA] xylem) were determined in well-watered (WW) and drought-stressed (DS) plants. At both stages, RWC and C l were hardly affected, significant decreases of the two parameters occurred only at severe soil water deficits; however, g s decreased much early at 2 and 1 days after imposition of stress (DAIS) at tuber initiation and tuber bulking, respectively, and coincided with decrease of C r and increase of [ABA] xylem ; while A decreased 2 days later than g s at each stage. Analyses of the pooled data of the two stages showed that g s was linearly correlated with [ABA] xylem at mild soil water deficits (i.e. C r > À0.3 MPa); photosynthetic water use efficiency, viz. A/g s , increased linearly with decreasing g s until the latter reached 0.2 mol m À2 s À1 , below this point, it decreased sharply. The results suggest that at mild soil water deficits, g s of potato is seemingly controlled by xylem-borne ABA. As a consequence of A being less sensitive than g s to soil drying, photosynthetic water use efficiency, i.e. A/g s , is increased at mild soil water deficits.
An investigation was carried out with paclobutrazol (PBZ) in order to study its effect on the photosynthetic and anatomical characteristics of Catharanthus roseus (L.) G. Don. The chlorophyll content and related parameters like net photosynthetic rate, transpiration rate and internal CO2 concentration were measured from control and treated plant samples. The anatomical characteristics, viz., leaf thickness, epidermis and cuticle, palisade layer, spongy layer and vascular bundle were studied. The root alkaloid ajmalicine was extracted and estimated from both treated and control plant roots. Photosynthetic pigment increased under PBZ treatment. PBZ treatment increased the net photosynthetic rate and internal CO2 concentration, but reduced transpiration. PBZ treatment increased the thickness of the leaf, epidermis and cuticle, palisade layer and spongy layer but reduced the diameter of xylem vessels significantly when compared to control, however the phloem elements had shown an increased diameter as compared to control in the PBZ treated plants. There was a significant enhancement in ajmalicine content under PBZ treatment when compared to control plants. The results suggested that the application of PBZ have significant effects on photosynthetic and anatomical responses thus can be used for improving productivity in medicinal plants.
Assimilate fluxes to/from various organs (J of sunflower (Helianthus annuus L.) were estimated in order to examine the following hypotheses: (1) plants with small storage capacity in stems as a result of short stature are able to maintain greater Jhead with consequently larger floret survival than taller plants when exposed to water stress before anthesis; and (2) plants with long stems (i.e. greater capacity to store assimilates) are able to maintain a greater Jseed than short-stature plants when exposed to water stress after anthesis.Assimilate fluxes were estimated using a budget accounting for labile carbohydrates, structural biomass and synthesis respiration, and maintenance respiration. Glasshouse-grown plants of three cultivars of different stature were compared under four water regimes.The reduction in floret number caused by water stress before anthesis was not related with Jhead. This, together with a greater concentration of labile carbohydrate in the heads of stressed plants relative to the well-watered controls, indicated that the survival of florets of water-stressed plants was probably not limited by assimilate availability.Seed filling depended strongly on stem assimilates as indicated by a significant negative association between Jseed and Jstem in the seed-filling period. The apparent contribution of stem assimilates to seed yield was cultivar dependent but was not strictly associated with plant height. The implications for selection of cultivars with improved mobilisation of stem assimilate to seeds are discussed.
The effects of triadimefon, a triazole compound on the antioxidant potentials and root alkaloid ajmalicine content were studied in two varieties, rosea and alba of Catharanthus roseus (L.) G. Don., an important medicinal plant. The plants of both the varieties were subjected to 15 mg l−1 triadimefon treatment by soil drenching on 53, 68 and 83 days after planting (DAP). The plants were harvested on 60, 75 and 90 days after planting and the antioxidant potentials and ajmalicine content were estimated. The antioxidant potentials viz., ascorbic acid (AA), α-tocopherol and reduced glutathione (GSH) were found increased under triadimefon treatment. The antioxidant enzymes like superoxide dismutase (SOD), ascorbate peroxidase (APX) and catalase (CAT) activities showed slight changes in both the varieties under triadimefon treatment when compared to control plants. Indole alkaloid ajmalicine content increased significantly under triadimefon treatment. The increase in ajmalicine content was more in rosea variety than in alba variety. These preliminary results suggest that, the application of triadimefon may be a useful tool to increase the alkaloid production in medicinal plants.
For adapted cultivars under normal crop densities, biological yield is largely determined by the pool of available resources, e.g. water, nutrients and photosynthetically active radiation, while the nature and intensity of intraspecific competition plays an important role in determining the magnitude of harvest index (HI). Water deficits can drastically reduce the HI from its genetic potential to zero. This study was conducted to determine the effect of drought-weighted intraspecific competition on the HI and, consequently, the grain yield in spring wheat populations along a natural moisture gradient in northwestern China. Along the natural moisture gradient (annual mean rainfall decreased 328→204→185 mm per year, supplemented with 70 mm of irrigation), culm size inequality (as measured by the Gini coefficient of above-ground biomass per culm) always increased, and Lorenz curves were more concave. HI decreased significantly in 1999 (0.364→0.345→0.307) and 2000 (0.341→0.303→0.251). There was a significant negative correlation between the Gini coefficient and the HI of spring wheat along the moisture gradient (R2=0.92, P<0.01). These results suggested that size hierarchies in spring wheat populations are closely correlated with the water regime in the field, and that under greater drought stress there are relatively more smaller plants with lower HI (size-dependent reproductive allocation). Size inequality is an index of competitive status in plant populations under stress environments. Agriculturally, greater size inequality may result in a competitive cost for energy and photosynthetic products, in other words, growth redundancy, which is detrimental to reproductive allocation and consequently, grain yield. The results support the view that stand uniformity in field crops is an important mechanism for increasing grain yield.
Aspen (Populus tremuloides Michx.) seedlings were grown in sand culture and subjected to mild and severe water deficit stress by withholding watering. Severely-stressed seedlings were also rewatered for 24 h to determine the effects of water deficit stress and stress recovery on root water flow properties. Both stress levels and stress recovery treatment reduced leaf stomatal conductance and shoot water potentials. However, root volume flux density and hydraulic conductivity were inhibited only by the severe water deficit stress and did not recover within 24 h following rewatering. The inhibition of root hydraulic conductivity in severely-stressed plants was accompanied by an increase in the proportion of apoplastic root water flow, as determined by the trisodium 3-hydroxy-5,8,10-pyrenetrisulfonate fluorescent tracer dye. In all treatments and control, the mean activation energy values for root water flow were lower than 6 kcal mol−1, pointing to the presence of AQP-mediated transport. However, compared with earlier studies using solution culture-grown aspen seedlings, mercuric chloride had relatively little effect on root volume flux density. We interpreted this result as likely due to limited penetration of the root cortex by mercuric chloride through the exodermal layer.
Environmental stresses trigger a wide variety of plant responses, ranging from altered gene expression and cellular metabolism to changes in growth rates and crop yields. A plethora of plant reactions exist to circumvent the potentially harmful effects caused by a wide range of both abiotic and biotic stresses, including light, drought, salinity, high temperatures, and pathogen infections. Among the environmental stresses, drought stress is one of the most adverse factors of plant growth and productivity. Understanding the biochemical and molecular responses to drought is essential for a holistic perception of plant resistance mechanisms to water-limited conditions. Drought stress progressively decreases CO2 assimilation rates due to reduced stomatal conductance. Drought stress also induces reduction in the contents and activities of photosynthetic carbon reduction cycle enzymes, including the key enzyme, ribulose-1,5-bisphosphate carboxylase/oxygenase. The critical roles of proline and glycine-betaine, as well as the role of abscisic acid (ABA), under drought stress conditions have been actively researched to understand the tolerance of plants to dehydration. In addition, drought stress-induced generation of active oxygen species is well recognized at the cellular level and is tightly controlled at both the production and consumption levels in vivo, through increased antioxidative systems. Knowledge of sensing and signaling pathways, including ABA-mediated changes in response to drought stress, is essential to improve crop management. This review focuses on the ability and strategies of higher plants to respond and adapt to drought stress.
Water is a key factor influencing the yield and quality of crops. Plants mainly adapt to water deficits by biochemical changes and osmotic adjustment (OA). Research on drought tolerance of field crops has been done intensively, but there is little work to be done in medical plants. Traditional Chinese medicine (TCM) has a long history of several thousand years. TCM is playing an important role in daily life in China and applied widely in clinical experience on the globe. More and more wild medical plants are cultivated and introduced. It is known that ecological and environmental conditions are vital to cultivation and efficient component accumulation of medical plants. This study is concerned about biochemical changes of three genotypes of Radix Astragali during water deficient periods and we evaluated the relative ability of their drought tolerance on the above basis. We analyzed the effect of soil water deficits on antioxidant enzymes activity and osmoregulation substances in R. Astragali leaves of three genotypes collected on day 0, 5, 10, 15, 20 and 25 after onset of water deprivation. Under water deficient conditions, biochemical changes include protecting enzyme system, for instance superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD). Osmoregulation matters include proline (Pro) and soluble sugar. Antioxidant enzyme activities and Pro, and soluble sugar content correlated between water deficient degree and time course. Antioxidant enzyme activities increased before 20 days, then decreased at the end of experiment. Proline content increased gradually, and soluble sugar content reached the highest on day 20. The order of the ability of drought tolerance in three genotypes of R. Astragali is Mongolia>Wild>Hebei by using index of drought tolerance. The research results are instructive for cultivation and introduction of R. Astragali under different conditions of water status.
In the present study, a pot culture experiment was conducted to estimate the ameliorating effect of propiconazole (PCZ) on drought stress in cowpea (Vigna unguiculata (L.) Walp.) plants. From 30 days after sowing (DAS), the plants were subjected to 3, 6 and 9 days interval drought (DID) stress and drought stress with PCZ at 15 and 15 mg l(-1) PCZ alone and 1 day interval irrigation was kept as control. The plant samples were collected on 34 DAS (3 DID), 37 DAS (6 DID) and 40 DAS (9 DID). The plants were separated into root, stem and leaf for estimating the antioxidant contents and activities of antioxidant enzymes. Individual and combined drought stress and PCZ treatments increased ascorbic acid (AA), alpha-tocopherol (alpha-toc) contents, superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and polyphenol oxidase (PPO) activities when compared to control. The PCZ treatment mitigated the adverse effects of drought stress by increasing the antioxidant potentials and thereby paved the way for overcoming drought stress in V. unguiculata plants.
Catharanthus roseus (L.) G. Don plants were grown in different water regimes in order to study the drought induced osmotic stress and proline (PRO) metabolism, antioxidative enzyme activities and indole alkaloid accumulation. The plants under pot culture were subjected to 10, 15 and 20 days interval drought (DID) stress from 30 days after sowing (DAS) and regular irrigation was kept as control. The plants were uprooted on 41DAS (10DID), 46DAS (15DID) and 51DAS (20DID). The drought stressed plants showed increased aminoacid (AA), glycine betaine (GB) and PRO contents and decreased proline oxidase (PROX) and increased gamma-glutamyl kinase (gamma-GK) activities when compared to control. The antioxidative enzymes like peroxidase (POX) and polyphenol oxidase (PPO) increased to a significant level in drought stressed plants when compared to control. The drought stressed C. roseus plants showed an increase in total indole alkaloid content in shoots and roots when compared to well-watered control plants. Our results suggest that the cultivation of medicinal plants like C. roseus in water deficit areas would increase its PRO metabolism, osmoregulation, defense system and the level of active principles.
The present investigation was conducted to determine whether CaCl(2) increases Catharanthus roseus drought tolerance and if such tolerance is correlated with changes in oxidative stress, osmoregulation and indole alkaloid accumulation. C. roseus plants were grown under water deficit environments with or without CaCl(2). Drought induced oxidative stress was measured in terms of lipid peroxidation (LPO) and H(2)O(2) contents, osmolyte concentration, proline (PRO) metabolizing enzymes and indole alkaloid accumulation. The plants under pot culture were subjected to 10, 15 and 20 days interval drought (DID) stress and drought stress with 5mM CaCl(2) and 5mM CaCl(2) alone from 30 days after planting (DAP) and regular irrigation was kept as control. The plants were uprooted on 41 DAS (10 DID), 46 DAS (15 DID) and 51 DAS (20 DID). Drought stressed plants showed increased LPO, H(2)O(2), glycine betaine (GB) and PRO contents and decreased proline oxidase (PROX) activity and increased gamma-glutamyl kinase (gamma-GK) activity when compared to control. Addition of CaCl(2) to drought stressed plants lowered the PRO concentration by increasing the level of PROX and decreasing the gamma-GK activities. Calcium ions increased the GB contents. CaCl(2) appears to confer greater osmoprotection by the additive role with drought in GB accumulation. The drought with CaCl(2)-treated C. roseus plants showed an increase in total indole alkaloid content in shoots and roots when compared to drought stressed and well-watered plants.
A pot culture experiment was conducted to estimate the drought stress mitigating effect of ketoconazole (KCZ), a fungicide cum plant growth regulator, in Catharanthus roseus plants. The plants under pot culture were subjected to drought stress and drought stress with KCZ from 30 days after sowing (DAS) and regular irrigation was kept as control. Antioxidant contents and activities of antioxidant enzymes were estimated from root, stem and leaf of both control and treated plants. The alkaloid ajmalicine was extracted and estimated from the roots of control, drought stressed and KCZ treated plants. Individual and combined drought stress and KCZ treatments increased ascorbic acid, alpha-tocopherol contents, superoxide dismutase, ascorbate peroxidase, catalase and polyphenol oxidase activities when compared to control. There was a significant enhancement in ajmalicine production under KCZ treated plants under drought stress when compared to well watered control as well as drought stressed plants. The KCZ treatment resulted in partial mitigation of drought stress by increasing the antioxidant potentials in C. roseus plants.
The effect of plant growth promoting rhizobacteria (PGPR) like Pseudomonas fluorescens on growth parameters and the production of ajmalicine were investigated in Catharanthus roseus under drought stress. The plants under pot culture were subjected to 10, 15 and 20 days interval drought (DID) stress and drought stress with Pseudomonas fluorescens at 1mgl(-1) and 1mgl(-1)Pseudomonas fluorescens alone from 30 days after planting (DAP) and regular irrigation was kept as control. The plants were uprooted on 41 DAS (10 DID), 46 DAS (15 DID) and 51 DAS (20 DID). Drought stress decreased the growth parameters and increased the ajmalicine content. But the treatment with Pseudomonas fluorescens enhanced the growth parameters under drought stress and partially ameliorated the drought induced growth inhibition by increasing the fresh and dry weights significantly. The ajmalicine content was again increased due to Pseudomonas fluorescens treatment to the drought stressed plants. From the results of this investigation, it can be concluded that, the seedling treatments of native PGPRs can be used as a good tool in the enhancement of biomass yield and alkaloid contents in medicinal plants, as it provides an eco-friendly approach and can be used as an agent in water deficit stress amelioration.
Catharanthus roseus (L.) G. Don. plants were grown with NaCl and CaCl2 in order to study the effect of CaCl2 on NaCl-induced oxidative stress in terms of lipid peroxidation (TBARS content), H2O2 content, osmolyte concentration, proline (PRO)-metabolizing enzymes, antioxidant enzyme activities, and indole alkaloid accumulation. The plants were treated with solutions of 80 mM NaCl, 80 mM NaCl with 5 mM CaCl2 and 5 mM CaCl2 alone. Groundwater was used for irrigation of control plants. Plants were uprooted randomly on 90 days after sowing (DAS). NaCl-stressed plants showed increased TBARS, H2O2, glycine betaine (GB) and PRO contents, decreased proline oxidase (PROX) activity, and increased gamma-glutamyl kinase (gamma-GK) activity when compared to control. Addition of CaCl2 to NaCl-stressed plants lowered the PRO concentration by increasing the level of PROX and decreasing the gamma-GK activities. Calcium ions increased the GB contents. CaCl2 appears to confer greater osmoprotection by the additive role with NaCl in GB accumulation. The antioxidant enzymes superoxide dismutase (SOD), peroxidase (POX) and catalase (CAT) were increased under salinity and further enhanced due to CaCl2 treatment. The NaCl-with-CaCl2-treated C. roseus plants showed an increase in total indole alkaloid content in shoots and roots when compared to NaCl-treated and untreated plants.
An experiment was conducted in two varieties, rosea and alba, of Catharanthus roseus plants with two watering treatments viz., 100 and 60% of field capacity, to understand the effects of water deficit on early growth, biomass allocation and photosynthetic pigment responses. We found that there were significant differences in early growth, dry matter accumulation and pigment variations between the two varieties. The root length, shoot length, total leaf area, fresh and dry weights were significantly reduced under water stress treatments. There was a significant reduction in the photosynthetic pigment contents in both the varieties. The rosea variety was more affected due to water deficit when compared to alba variety.
In the present work, we have analysed the changes in the reactive oxygen metabolism of Catharanthus roseus (L.) G. Don. plants in terms of H(2)O(2) content, lipid peroxidation and the free radical quenching systems (non-enzymatic and enzymatic antioxidants) under drought stress. In addition to this, the root alkaloid ajmalicine was extracted and quantified from both control and drought stressed plants. The H(2)O(2) content was analysed from both stressed and unstressed control plants. Lipid peroxidation was estimated as thiobarbituric acid reactive substances. The non-enzymatic antioxidants viz., ascorbic acid, alpha-tocopherol and reduced glutathione contents, antioxidant enzymes like superoxide dismutase, ascorbate peroxidase, and catalase were extracted and estimated from the samples. The alkaloid ajmalicine was extracted and quantified from shade dried root samples and found significantly increased over control. From the results of this investigation, it can be concluded that the water deficit areas may be well used for the cultivation of medicinal plants like C. roseus and the economically important alkaloid production can be enhanced in the plant level.
Triadimefon (TDM), a systemic fungicide with non-traditional plant-growth regulator properties, was administered to Catharanthus roseus (L.) G. Don. plants in order to determine its effects on oxidative injury in terms of H2O2 content, lipid peroxidation (LPO), electrolyte leakage (EL), protein and amino acid contents, as well as proline metabolism. The LPO, estimated as thiobarbituric acid-reactive substances (TBARS), decreased under TDM treatment. It was found that H2O2 and EL were reduced under TDM treatment when compared to control. TDM treatment caused a significant increase in the protein and amino acid contents. Glycine betaine (GB) and proline (PRO) significantly accumulated in C. roseus under stress arisen from fungicide applications. Proline oxidase (PROX) activities reduce the PRO content and gamma-glutamyl kinase (gamma-GK) accelerates the synthesis of PRO. Under TDM treatment, the activity of PROX decreased and the gamma-GK activity increased. From our results, it is suggested that fungicide triadimefon causes activation of metabolic processes in the medicinal plant Catharanthus roseus. These findings are of great significance for the cultivation of this medicinal plant, as it was previously reported that TDM causes an enhancement of antioxidant metabolism and ajmalicine production in C. roseus.
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