Article

Salt sensitivity in chickpea (Cicer arietinumL.): Ions in reproductive tissues and yield components in contrasting genotypes

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Salt sensitivity in chickpea (Cicer arietinumL.): Ions in reproductive tissues and yield components in contrasting genotypes

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Abstract

The reproductive phase in chickpea (Cicer arietinum L.) is affected by salinity, but little is known about the underlying cause. We investigated whether high concentrations of Na(+) and Cl(-) in the reproductive structures influence reproductive processes. Chickpea genotypes contrasting in tolerance were subjected to 0, 35 or 50 mM NaCl applied to soil in pots. Flower production and abortion, pod number, percentage of empty pods, seed number and size, were evaluated. The concentrations of Na(+) , K(+) and Cl(-) were measured in various plant tissues and, using X-ray microanalysis, in specific cells of developing reproductive structures. Genotypic variation in reproductive success measured as seed yield in saline conditions, was associated with better maintenance of flower production and higher numbers of filled pods (and thus seed number), whereas seed size decreased in all genotypes. Despite the variation in reproductive success, the accumulation of Na(+) and Cl(-) in the early reproductive tissues of developing pods did not differ between a tolerant (Genesis836) and a sensitive (Rupali) genotype. Similarly, salinity tolerance was not associated with the accumulation of salt ions in leaves at the time of reproduction or in seeds at maturity. This article is protected by copyright. All rights reserved.

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... Plants such as chickpea tolerate salinity by (a) restricting the entry of Na + and Clat the roots, (b) sequestering these ions in lower leaves, thereby maintaining Na + and Cl -concentrations in young leaves at levels that do not markedly reduce photosynthesis, and/or (c) tolerating these ions in young developing tissues (Munns and Tester, 2008). Exposure to salinity increases the leaf concentration of Na + and Cl -, particularly Cl - (Kotula et al., 2015;Pushpavalli et al., 2016;Turner et al., 2013), but Na + results in much greater adverse effects than Cl - (Khan et al., 2016). A negative association between Na + in the leaves and yield in saline soil has been observed, but not universally (Pushpavalli et al., 2016;Turner et al., 2013). ...
... Na + accumulation in young and old green leaves has been associated with a greater delay to flowering, which was in turn associated with a decline in seed yield in saline soil (Pushpavalli et al., 2016) and also with a decrease in leaf photosynthesis and structural damage to the mesophyll cells (Kotula et al., 2019). Na + and Clconcentrations in reproductive tissues were not associated with yield in saline conditions or salt tolerance/sensitivity (Kotula et al., 2015). ...
... While there are conflicting results of the effect of exclusion and/or accumulation of Na + , K + and Clon the growth and yield of chickpeas that may influence the genotypic susceptibility/tolerance in saline soil (Kotula et al., 2015(Kotula et al., , 2019Pushpavalli et al., 2016;Turner et al., 2013), in the present study growth in saline soil increased Na + , K + and Clconcentrations in young leaves by 55%, 38% and 212%, respectively, and in old leaves by 41%, 47% and 124%, respectively. Thus, we conclude that salinity induced the accumulation of all three ions, particularly Clin the young leaves, but did not sequester ions in old leaves as has been suggested as a mechanism for salt tolerance. ...
Article
Chickpea (Cicer arietinum L.) is a moderately salt-susceptible grain legume species. Genotypic differences in salt tolerance/susceptibility have been identified in chickpea genotypes grown in adequately-watered soil in pots with different salt concentrations, but few studies have been conducted in saline fields. This three-year study compared the growth and yield of chickpea genotypes to determine whether genotypic differences in salt tolerance/susceptibility identified in glasshouse pot experiments applied when grown in a dryland saline field. The emergence, phenology, growth, leaf ion concentration, yield and yield components of 10–20 chickpea genotypes were compared under controlled saline and water conditions in the glasshouse, and saline and non-saline conditions in the field in a semiarid environment. In the field, soil salinity and yields varied from year to year in the non-saline and saline treatments. Genotypic differences in salt tolerance and sensitivity were observed in the controlled salt and water conditions in the glasshouse. The salt tolerant and salt sensitive check genotypes, GENESIS 836 and RUPALI, respectively, grown in all three comparison years were similarly tolerant and sensitive in the glasshouse and dryland field in all three comparison years. However, other genotypes selected for salt tolerance under controlled conditions were not observed to be tolerant in the dryland field. While salinity slowed the rate of emergence and increased the time to flowering, the variation in saline yields among genotypes was associated with aboveground biomass, filled pod number and seed number at maturity in both the glasshouse and field, but not the number of emerged plants that survived to maturity or the delay in flowering. Salinity significantly increased the leaf Na⁺, K⁺ and Cl⁻ concentrations in the glasshouse and field (except in the glasshouse in 2010). Na⁺ increased in young and old leaves by 28–84%, but the concentrations of Na⁺ or K⁺ in the leaves across genotypes was not correlated with yield in saline soil. Salinity increased leaf Cl– concentrations by 80–290%; the increase in young leaves had a significant association with reduced yield among genotypes only in the glasshouse in one year. We conclude that selection under controlled soil salinity and water content in pots can identify some genotypes that are salt tolerant, but for dryland saline environments verification of their tolerance in comparable environments is essential.
... A greater number of flowers are considered to be a more important measure of tolerance during stress rather than acquiring greater root or shoot biomass [24,35]. For example, Vadez [18], found that tolerant lines produced 70 per cent and 30 per cent more flowers under salt stress at sowing and flowering, respectively [35,36]. Physiological studies have shown that salinity delays flowering time and severely affected during the pod filling stage. ...
... Physiological studies have shown that salinity delays flowering time and severely affected during the pod filling stage. Despite pollen viability, sensitive genotypes show higher occurrence of empty pods and seed abortions [24,36]. This observation suggests failure in ovule fertilisation as the main reason for pod abortion or empty pods, despite the viable pollen and pollen tube growth. ...
... Reducing the (Na + , K + and Cl -) ion accumulation in shoots by manipulating the root ion transport processes was used to explain the ion-exclusion mechanism in plants [11,40]. However, this may not be the case with chickpea where tolerant and sensitive genotypes have equal ionic concentrations in shoots [36,37]. Also, fully expanded leaves maintained high Na + and Clion concentrations compared to reproductive organs during the pod filling stage and eventually restricted ions from accumulating in flowers and developing ovules [11,41]. ...
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Introduction: The high protein value, essential minerals, dietary fibre and notable ability to fix atmospheric nitrogen make chickpea a highly remunerative crop, particularly in low-input food production systems. Of the variety of constraints challenging chickpea productivity worldwide, salinity remains of prime concern owing to the intrinsic sensitivity of the crop. In view of the projected expansion of chickpea into arable and salt-stressed land by 2050, increasing attention is being placed on improving the salt tolerance of this crop. Considerable effort is currently underway to address salinity stress and substantial breeding progress is being made despite the seemingly highly-complex and environment-dependent nature of the tolerance trait. Conclusion: This review aims to provide a holistic view of recent advances in breeding chickpea for salt tolerance. Initially, we focus on the identification of novel genetic resources for salt tolerance via extensive germplasm screening. We then expand on the use of genome-wide and cost-effective techniques to gain new insights into the genetic control of salt tolerance, including the responsive genes/QTL(s), gene(s) networks/cross talk and intricate signalling cascades.
... Plants were grown in plastic pots (8.1 L in volume) with drainage holes (see below for imposition of waterlogging treatments) filled with 5 kg of soil overlying 2 kg of coarse gravel and 1 kg of fine gravel. The soil was a red-brown sandy clay loam (Calcic Haploxeralf) of pH 8.2, electrical conductivity (EC) of 0.4 dS/m in 1:5 soil:water extract (Kotula et al. 2015). The water content (w/w) at field capacity (i.e. ...
... The water content (w/w) at field capacity (i.e. pot capacity when fully-drained) was 17.8% (Kotula et al. 2015). This soil type was suitable for all three species as M. siculus prefer neutral to alkaline soils, M. polymorpha alkaline soils (Nichols et al. 2008;Bonython et al. 2011), and T. michelianum has broad adaptation to soil pH . ...
... The soil was dried in a soil-drying room at the UWA Plant Growth Facility prior to filling the pots. Soil in each pot had mineral nutrients added according to Kotula et al. (2015), but NO 3 − was excluded and replaced by salts with SO 4 2− as the anion, so that nodulation was not inhibited by high soil N-status (Pate and Dart 1961). Nutrient salts added to the soil (g/pot containing 5 kg soil) were 0.646 K 2 SO 4 , 1.123 CaSO 4 .2H 2 O, 0.954 KH 2 PO 4 , 0.125 MgSO 4 .7H 2 O, and 3.5 ml of half-strength Hoagland solution micronutrients. ...
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Aims This study evaluated the responses to and recovery from soil waterlogging, soil salinity and the combination of these stresses of the annual pasture legumes Melilotus siculus cv. Neptune, Trifolium michelianum cv. Frontier and Medicago polymorpha cv. Scimitar. The major aim was to test the tolerance of these plants to salinity and waterlogging in soil inoculated with rhizobia, adding to previous controlled-environment studies, which have used nutrient solution cultures, as well as to examine post-stress recovery. Methods Plants were grown in pots of soil inoculated with their appropriate species-specific rhizobia. Drained non-saline controls, and waterlogged non-saline, drained saline (100 mM NaCl) and waterlogged saline treatments were imposed for 3 weeks, followed by a 4 week recovery period. Results In the waterlogged saline soil, shoot dry mass of M. siculus was 63% of the control, compared to 10% for T. michelianum and 5% for M. polymorpha, and after the recovery phase was 75% of the control for M. siculus, 58% for T. michelianum and 4% for M. polymorpha. Foliar Na⁺ concentrations of T. michelianum and M. polymorpha were 2.8-fold higher than for M. siculus. Conclusions The greater tolerance of M. siculus can be attributed to regulation of leaf Na⁺ concentrations in saline conditions and the formation of aerenchymatous phellem to enhance O2 supply to roots in waterlogged soils. This controlled glasshouse study using pots of soil supports earlier nutrient solution experiments and field observations that M. siculus possesses greater tolerance of combined waterlogging and salinity, than T. michelianum and M. polymorpha.
... Several factors have been proposed to underlie the inhibition of growth and reproduction induced by salinity, including the accumulation of toxic ions such as Na + , K + deficiency, plant hormone imbalance, and carbon supply reduction Cuartero and Fernández-Muñoz, 1998;Munns, 2002;Plackett et al., 2011;Yang et al., 2017). In salt-sensitive chickpea (Cicer arietinum) plants, for example, treatment with 50 mM NaCl stimulates flower and pod abortion and reduces seed number (Kotula et al., 2015). ...
... The reproductive processes of non-halophytes are considered to be salt sensitive Vadez et al., 2007Vadez et al., , 2012Samineni et al., 2011;Turner et al., 2013;Deng et al., 2016). Salinity largely inhibits reproductive organ formation (Li et al., 2007), decreases fertility (Amzallag, 2005), and reduces pollen tube growth in the style (Baby et al., 2016); thus, it also reduces seed number (Kotula et al., 2015). For example, in Arabidopsis, NaCl (200 mM) stress for 4 h resulted in a statistically insignificant reduction in fertility, but when maintained for longer than 12 h it resulted in a maximal decrease in reproduction, such that only 5% of ovules formed seeds (Sun et al., 2004). ...
... Thus, the reproductive growth (flower differentiation and seed development) of S. salsa requires a certain concentration of external NaCl. By contrast, the reproductive growth of non-halophytes is greatly limited by NaCl (Kotula et al., 2015). ...
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Halophytes are adapted to saline environments and demonstrate optimal reproductive growth under high salinity. To gain insight into the salt tolerance mechanism and effects of salinity in the halophyte Suaeda salsa, the number of flowers and seeds, seed size, anther development, ion content, and flower transcript profiles, as well as the relative expression levels of genes involved in ion transport, were analyzed in S. salsa plants treated with 0 or 200 mM NaCl. The seed size, flower number, seed number per leaf axil, and anther fertility were all significantly increased by 200 mM NaCl treatment. The Na⁺ and Cl⁻ contents in the leaves, stems, and pollen of NaCl-treated plants were all markedly higher, and the K⁺ content in the leaves and stems was significantly lower, than those in untreated control plants. By contrast, the K⁺ content in pollen grains did not decrease, but rather increased, upon NaCl treatment. Genes related to Na⁺, K⁺ and, Cl⁻ transport, such as SOS1, KEA, AKT1, NHX1, and CHX, showed increased expression in the flowers of NaCl-treated plants. These results suggest that ionic homeostasis in reproductive organs, especially in pollen grains under salt-treated conditions, involves increased expression of ion transport-related genes.
... As compared to the gathering of root and shoot mass by the plant, normal flowering and flower development in a plant is an indication of tolerance during salinity stress (Vadez et al. 2012a). The observations on number of flowers on plants under salt stress recorded by Vadez et al. (2012b) in chickpea were well supported by Kotula et al. (2015). Physiological studies have also shown delayed flowering, failure of fertilization even after the development of pollen tube resulting into poor pollen viability affecting pod filling and is also affected resulting in empty pods (Kotula et al. 2015). ...
... The observations on number of flowers on plants under salt stress recorded by Vadez et al. (2012b) in chickpea were well supported by Kotula et al. (2015). Physiological studies have also shown delayed flowering, failure of fertilization even after the development of pollen tube resulting into poor pollen viability affecting pod filling and is also affected resulting in empty pods (Kotula et al. 2015). The leaf area, dry weight, and chemical analysis by atomic absorption spectrophotometer and chloride content by Mohr's volumetric method, relative water content (Subbarao et al. 1990), membrane stability index chlorophyll content, K + /Na + estimation (Sherawat et al. 2013) and SCMR (Spad chlorophyll metre reading) and shoot sodium accumulation (Srivastava et al. 2007) can be used for screening and identifying tolerant and susceptible genotypes. ...
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The mechanism of salinity stress and plant’s response towards changes in morphological, physiological, biochemical and molecular features have been delineated in detail. Effective breeding approaches and progress in development of salt tolerant pulse crops have been highlighted. However, current leads in understanding the mechanism of salt stress and the genotypes developed may not be sufficient to enhance the productivity and availability of the pulse crops. The kind of efforts needed to improve pulse crops are rare and hence, require special attention. Therefore, integration of the traditional and modern breeding approaches including ‘omics’ technologies and biological agents are needed to address the issue of salt stress effectively. The development of stress tolerant pulse crops through genetic engineering has also shown promise. High-quality genotypic and phenotypic data including high throughput imaging approaches might lead to proper understanding of the mechanism of salt tolerance which in turn would help designing effective breeding programme for the development of pulse crops tolerant to salinity stress.
... Basal fertiliser (urea, triple superphosphate, and sulphate of potash), comprising 190 mg kg −1 N, 110 mg kg −1 P, and 130 mg kg −1 K dry soil, was mixed into the top 20 cm of soil in each rhizobox [33]. Each rhizobox received an equal amount of macro-and micro-nutrients from commercial liquid fertiliser (Thrive; Yates, Australia) on a % w/v basis, with N (11), P (2. [34,35]. ...
... Soybean seeds were surface sterilised with 1% NaClO solution, rinsed thoroughly with deionised water, placed on moistened filter paper inside Petri dishes, and seeds kept covered with aluminium foil to ensure darkness overnight to ease germination [34]. Two pre-germinated seeds were sown directly into the soil in each rhizobox (replicate), close to the glass wall and equidistant from one another. ...
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Root-system architecture is vital for improving soybean (Glycine max L.) growth and nutrient uptake. We characterised root-system architecture and shoot traits of 30 soybean genotypes in a semi-hydroponic system 35 days after sowing (DAS) and validated eight genotypes with contrasting root-system architecture in 1.5 m-deep rhizoboxes at the flowering stage. Among them, two genotypes were selected for evaluation through to maturity. Abundant variation (coefficient of variation values ≥ 0.25) was observed in 11 of 13 measured roots and shoot traits during the early growth stage. After late growth stages, strong positive correlations were found between root traits and shoot traits, except for specific root length and diameter. Seed yield and yield traits at final harvest significantly differed between two contrasting soybean genotypes. The large-rooted genotype had a higher harvest index than the small-rooted genotype. Soybean genotypes with larger root systems had a long time to flowering than those with smaller root systems. Genotypes with large-root systems had 106% more leaf area, and 245% more shoot dry weight than those with small systems, presumably due to high canopy photosynthesis to supply the demand for carbon assimilates to roots. Total root length, and root: shoot ratio-traits data collected in the rhizobox study, strongly correlated with the same traits in the semi-hydroponic phenotyping system. We found genetic variation and phenotypic plasticity in other root and shoot traits such as taproot depth, root dry weight, specific root length, and average root diameter among the tested genotypes. Phenology, particularly time to flowering, was associated with root system size. Some root and shoot traits in the semi-hydroponic phenotyping system at the seedling stage produced similar rankings at the later phenological (flowering) stage when grown in the soil-filled rhizoboxes. The soybean genotypes characterised by vastly different root traits could be used for further glasshouse and field studies to improve adaptation to drought and other specific environments.
... Salinity adversely affects chickpea germination (Khalid et al., 2001), vegetative growth (Lauter and Munns, 1986a;Khan et al., 2015), and especially reproductive processes (Vadez et al., 2007(Vadez et al., , 2012Samineni et al., 2011;Turner et al., 2013;Khan et al., 2017). There is, however, variation for salt tolerance within cultivated chickpea genotypes (Vadez et al., 2007;Turner et al., 2013), but the physiological mechanisms conferring these differences in salt tolerance are not fully understood Kotula et al., 2015). ...
... Two desi-type chickpea (Cicer arietinum L.) genotypes that are classified as either salt tolerant (Genesis836) or salt sensitive (Rupali) based on previous experiments with salinized soil (Turner et al., 2013, Kotula et al., 2015 or nutrient solution (Khan et al., , 2016 were used. Seeds were washed with 0.04% (w/v) sodium hypochlorite, the seed coat was pricked, and the seeds were imbibed in aerated 0.5 mM CaSO 4 for 3 h and then placed on plastic mesh floating on 10% strength nutrient solution (Khan et al., , 2016Supplementary Table S1 at JXB online). ...
Article
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Salinity tolerance is associated with Na 'exclusion' from, or 'tissue tolerance' in, leaves. We investigated whether two contrasting chickpea genotypes, salt-tolerant Genesis836 and salt-sensitive Rupali, differ in leaf tissue tolerance to NaCl. We used X-ray microanalysis to evaluate cellular Na, Cl and K concentrations in various cell-types within leaflets and also in secretory trichomes of the two chickpea genotypes in relation to photosynthesis in control and saline conditions. Transmission electron microscopy was used to assess the effects of salinity on the ultrastructure of chloroplasts. Genesis836 maintained net photosynthetic rates (A) for the 21 d of salinity treatment (60 mM NaCl), whereas A in Rupali substantially decreased after 11 d. Leaflet tissue [Na] was low in Genesis836 but had increased markedly in Rupali. In Genesis836, Na was accumulated in epidermal cells but was low in mesophyll cells, whereas in Rupali cellular [Na] was high in both cell types. The excessive accumulation of Na in mesophyll cells of Rupali corresponded with structural damage to the chloroplasts. Maintenance of photosynthesis and thus salinity tolerance in Genesis836 was associated with an ability to 'exclude' Na from leaflets and in particular from the photosynthetically-active mesophyll cells, and to compartmentalise Na in epidermal cells.
... Medias con letras iguales no difieren según la prueba de comparación múltiple de Duncan HSD ** y * = diferencias para el 5 % y 1 % respectivamente por t-student; (±)=error estándar de la media Variedad Na*10 -2 ( g kg -2 ) K *10 -2 ( g kg -2 ) Cu ( mg kg -1 ) Mn ( mg kg -1 ) En estudios recientes en este cultivo frente al estrés salino, se reportaron niveles bajos de Na + en algunos órganos y tejidos reproductivos y se infiere que es poco probable que afecten adversamente los procesos reproductivos (15,32,33). ...
Article
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Chickpea (Cicer arietinum L.) is considered a species sensitive to salinity, but there are differences in the degree of tolerance to this type of stress. The present study was carried out to determine the tolerance to salinity of some cuban cultivars of chickpea and its relationship with indicators of the development and accumulation of ions in the different organs of the plant. For this, eight chickpea cultivars exposed to two treatments, 0 and 50 mM NaCl, were studied. The results showed that the cultivars Nac-29, Nac-5HA and JP-94 were the ones that showed the highest degree of tolerance to salinity. The cultivar N-29 turned out to be more tolerant and although it diminished its growth, the results show that it also accumulated less quantity of ions in the different organs of the plant, in the two conditions of imposed salinity. Therefore, it can be inferred that the reduction in growth was related to some inability of the chickpea plants to prevent high concentrations of saline ions from reaching the leaves, resulting in considerable variability in the degree of tolerance to salinity the cultivars evaluated
... season delays the onset of podding in chickpea, exposing the crop to higher temperature and terminal drought (Berger et al., 2012), while in India, chickpea production has expanded to the warmer central and southern states where it is exposed to increasing terminal drought and heat stress. Salinity is an increasing issue for chickpea production globally, when the crop is grown on marginal lands, where irrigation is salinizing cropping areas, or when grown in heavy, alkaline, sodic soils (Canci & Toker, 2009;Kotula et al., 2015;Li et al., 2018). Thus, all three stresses (drought, heat and salinity) are of global importance and adversely affect crop production, even though they play out differently according to region. ...
Article
Chickpea crops are often exposed to a combination of drought, heat and salinity stresses during the reproductive stage. Previous efforts have largely focused on these stresses in isolation, such that we do not understand whether genotypes tolerant to one stress can withstand other stresses. Around 22–44 chickpea genotypes contrasting for tolerance to drought, salinity or heat in previous studies were exposed to terminal drought (TD, 3 experiments) and to salinity (SAL, 1 experiment). A priori stress tolerance to any of the listed stresses was generally reflected in drought and salinity tolerance in the present study. Thus, the drought‐, heat‐ and salt‐tolerant groups (DT, HT and ST) produced higher seed yield, had earlier phenology, higher harvest indices and seed yield transpiration efficiencies compared with sensitive groups (DS, HS and SS). However, tolerance did not select for prescriptive water use patterns. Despite our efforts to remove the confounding effects of phenology, 4–9 days variation in flowering time made a significant difference in productivity and differentiated tolerant from sensitive counterparts. In TD1, TD2 and SAL, all tolerant groups yielded similarly under stress conditions. This showed the existence of cross‐tolerance in chickpea where tolerant genotype selected for an individual stress can yield well under other stresses too.
... Our results implied that some pomegranate cultivars had a higher ability of K and Ca transport into shoots and leaves, and then maintained a suitable K/Na or Ca/Na ratio for normal metabolism [31,39,40]. These results were similar to those on oak (Quercus virginiana) [37] and chickpea (Cicer arietinum) [41] in saline conditions, in which it was reported that the higher capacity for K and Ca transport to the aerial part would contribute to mitigating the ion toxicity in leaf cells. Mg serves as a chlorophyll component and activator involved in photosynthesis, and the decrease of leaf Mg concentration might be one reason for photosynthesis impairment (Table 5) [42]. ...
Article
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Pomegranate (Punica granatum L.) is widely grown in arid and semiarid regions, where the salinization may have developed through irrigation. A greenhouse experiment was conducted to investigate NaCl stress on growth, photosynthesis, and nutrients of 18 pomegranate cultivars. One group was irrigated twice a week with a nutrient solution. The other group was watered twice a week with the same nutrient solution and 200 mM NaCl for five weeks. Dry weight, shoot length, new shoot number, root length and number, leaf area, leaf relative water content, and net photosynthesis of salt-treated plants were negatively impacted by salt stress, and there was a significant difference among cultivars. Few foliar damages were observed. Na content of plants significantly increased in all cultivars, while P, S, K, Ca, Mg, Si, Al, Zn content of plants decreased under salt stress. Fe, Mn, and Cu content increased in most cultivars. Pomegranate accumulated supraoptimal Na mostly in roots and transported more K and Ca to shoots, which was attributed to maintaining a higher ratio of K/Na and Ca/Na in the aerial part of plants. Ten of the 18 cultivars were considered salt-tolerant, which would offer a reference for pomegranate cultivation on saline lands.
... Leguminous crops are believed to be quite sensitive to salt stress, which is one of the main constraints of the enhancement of pulse production on saline lands (Farooq et al., 2017). It is well-known that chickpea is especially susceptible to salt stress at the reproductive stage of growth (Kotula et al., 2015), and firstly, the crop roots suffer (Tejera et al., 2006) resulting in worse productivity (Singla & Garg, 2005;Sohrabi et al., 2008). It has been proved that salinity stress causes decrease in the crop growth rate by 20%, plant height by 15%, and total biomass of the plants by 28% (Atieno et al., 2017). ...
Article
Chickpea (Cicer arietinum L.) is one of the main pulse crops cultivated mostly in the arid and semi-arid regions of the world, very often on saline lands. The problem is that it has not been clearly determined yet what is the safe salinity degree for obtaining uniform and vigorous sprouts of the crop without significant suppression in the parameters of initial growth and development. The goal of our study was to determine the effect of different NaCl concentrations in solutions on chickpea germination and initial growth to determine the safe degree of salinity for the crop cultivation. The study was carried out in greenhouse conditions of Kherson State Agrarian University. We studied the effect of five different gradually increasing degrees of NaCl solutions on the germination percentage and initial growth of chickpea (variety Rosanna, kabuli type) that was germinated in laboratory conditions in flasks filled with sand, at the temperature of 25 oC. A significant decrease in all the studied parameters was observed with the increase of salinity degree. However, we think that a considerable decrease of the crop germination and initial growth started with NaCl concentration of 1.79 g/L: germination percentage decreased by 33.9%, plant height – by 7.8 cm, root length – by 5.5 cm in comparison to the control variant (not saline conditions). Therefore, we conclude that the chickpea can be efficiently cultivated on slightly-saline lands. Besides, the results of linear regression analysis revealed that the most susceptible stage of chickpea growth and development is germination because this stage had strong close inter-connection with the degree of salinity. Further growth of the crop was less affected by the salinity stress. We recommend cultivation of chickpea on the saline lands only with a slight salinity level.
... Free-draining pots contained gravel at the bottom and 3.5 kg sand and soil mixed (1:1) [pH 6.7 and electrical conductivity (EC) 0.46 dS m −1 at 1:5 w/v soil/water] at the top. Soil was collected from Mukinbudin (30 • 78 S, 118 • 31 E), Western Australia ( Kotula et al., 2015). Each freedraining pot (19-cm height × 21-cm diameter) was placed in a sealed base pot (24-cm height × 26-cm diameter). ...
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In the Eastern Gangetic Plain of South Asia field pea (Pisum sativum L.) is often grown as a relay crop where soil waterlogging (WL) causes germination failure. To assess if selection for WL tolerance is feasible, we studied the response to WL stress at germination stage in a recombinant inbred line (RIL) population from a bi-parental cross between WL-contrasting parents and in a diversity panel to identify extreme phenotypes, understand the genetics of WL tolerance and find traits for possible use in indirect selection. The RIL population and the diversity panel were screened to test the ability of germination under both waterlogged and drained soils. A total of 50, most WL tolerant and sensitive, genotypes from each of both the RIL and the diversity panel were further evaluated to assay testa integrity/leakage in CaSO4 solution. Morphological characterization of both populations was undertaken. A wide range of variation in the ability to germination in waterlogged soil was observed in the RIL population (6–93%) and the diversity panel (5–100%) with a high broad-sense heritability (H2 > 85%). The variation was continuously distributed indicating polygenic control. Most genotypes with a dark colored testa (90%) were WL tolerant, whereas those with a light colored testa were all WL sensitive in both the RIL population and diversity panel. Testa integrity, measured by electrical conductivity of the leakage solute, was strongly associated with WL tolerance in the RIL population (rG = −1.00) and the diversity panel (rG = −0.90). Therefore, testa integrity can be effectively used in indirect selection for WL tolerance. Response to selection for WL tolerance at germination is confidently predicted enabling the adaptation of the ancient model pea to extreme precipitation events at germination.
... Chickpea (Cicer arietinum L.) is an economically important crop cultivated worldwide, and rich in carbohydrates, fats and proteins used in human and animal nutrition (Rasool et al., 2015). Chickpea is sensitive to several stresses, such as water deficit and salinity which reduce its growth, performance and yield (Kotula et al., 2015;Ahmad et al., 2016). Patel et al. (2012) reported the negative impacts of salinity stress on chickpea growth and performance which were then improved upon PGPR inoculation. ...
Article
High salinity restricts crop growth and yield. Plant growth-promoting soil rhizobacteria boost crops growth and ameliorate the adverse effects of salt stress through regulating several physiological, biochemical and molecular processes. This study investigated the effects of Azospirillum lipoferum FK1 strain on chickpea (Cicer arietinum L.) growth and performance under saline conditions (0, 75 and 150 mM NaCl). Salt stress adversely decreased growth, biomass yield, nutrient acquisition, chlorophyll content, gas exchange parameters and total phenolic and flavonoid content of chickpea plants. However, salt stress induced the carotenoid content, osmolytes level, electrolyte leakage, H2O2 content, malondialdehyde level, and levels of enzymatic and non-enzymatic antioxidants in chickpea. Moreover, the expressions of three antioxidants genes (CAT, APX and SOD) and six genes conferring abiotic stress tolerance (PAL, PPO, CHS, CHI, DREB2A and IFS) was induced by high salinity. On the other hand, inoculation of salt-treated chickpea plants with Azospirillum lipoferum FK1 significantly improved nutrient acquisition, growth, biomass, photosynthetic pigment synthesis, osmolytes level, gas exchange attributes, phenols and flavonoids content, and enzymatic and non-enzymatic antioxidant levels in chickpea plants when compared to those exposed to NaCl only. Moreover, inoculated plants revealed lower levels of electrolyte leakage, H2O2 and MDA under saline conditions in relative to plants subjected to salt alone. Inoculated plants exhibited the highest expression level of the antioxidants genes and genes conferring salt tolerance under 150 mM NaCl concentration. Taken together, these findings demonstrated the beneficial role of Azospirillum lipoferum FK1 in alleviating the inhibitory impacts of salinity on chickpea growth via modulating osmolytes, antioxidants machinery and stress-related genes expression.
... Salt sensitivity has been studied in chickpea using various approaches: studying the expression changes in genes such as lipid transfer proteins (Car LTPs), late embryogenesis abundant 1 and 2 (Car LEA1, Car LEA2) (Romo et al., 2001), early responsive to dehydration (ERD1 to ERD16) (Alves et al., 2011), and LEA-related hydrophilins (Battaglia et al., 2008); plasma membrane (PM) H + -ATPase (SOS1) and vacuolar (V) H + -ATPase and H + -PPase; osmotic stress-induced calcium-dependent protein kinases (CDPKs) and calcineurin B-like (CBL) proteins (for Ca 2+ -dependent pathways for the regulation of ion homeostasis and plant salt tolerance through Na + extrusion) ( Bartles and Sunkar, 2005); salt-regulated TFs such as WRKY33 and MYB51, salt tolerance zinc finger (STZ), and dehydration responsive element (DRE)-binding TFs (DREBs); physiological parameters, trait changes in sensitive and varieties, with tolerance ranging from 25 mM NaCl to highly resistant genotypes surviving up to 90 mM NaCl under hydroponic conditions (Flowers et al., 2010;Kotula et al., 2015;Khan et al., 2016;Ahmad et al., 2016;Abdel Latef et al., 2017;Sen et al., 2017;Kaashyap et al., 2017). ...
... About 26,000 genes and many molecular pathways were identified in Arabidopsis (Pastore et al. 2011), including $80 genes involved in flowering regulation. Some abiotic stress factors, such as cold, osmotic stress, and salinity can also delay flowering, similar to chronic radiation (Srinivasan et al. 1999;Kotula et al. 2015). Cold temperatures induced degradation of the CO protein via the ubiquitin/proteasome pathway (Jung et al. 2012). ...
Article
Purpose: Chronic and acute irradiations have drastic effects on flowering stage that plays an important role in the further seed development and can determine seed yield. The expression of the key flowering genes, AP1, CO, GI, FT, FLC, and LFY, sensitive to irradiation repair gene RAD51 and the proliferation gene PCNA2 were studied in the wild type Arabidopsis thaliana (Columbia ecotype) under chronic and acute irradiations. Materials and methods: Chronic irradiation was performed using the radioactive isotope ¹³⁷СsCl in two total doses of 3 cGy and 17 cGy, with the dose rate of 10⁻⁷ cGy/sec and 6.8 10⁻⁶ cGy/sec, respectively. The plants were grown under chronic irradiation during 6 weeks, from seeds till the 6.3 stage of flowering. For acute exposure, the plants were X-ray irradiated one time at the 5.0 development stage (20 days old) by a total dose of 15 Gy with the dose rate of 89 cGy/sec. Results: After chronic irradiation with the 3 cGy dose the irradiated plants demonstrated 8 ± 2.8 days earlier flowering than in the control group. However, at the 17 cGy chronic and at the 15 Gy acute doses plants showed 14 ± 3.7 and 2 ± 1.4 days later flowering, respectively. The 3 cGy chronic exposure significantly increased the expression of the CO gene by a factor of 1.152 (1.087-1.217 95% C.I.) and decreased the expression of the FT gene by a factor of 0.128 (0.021-0.396 95% C.I.). The 17 cGy chronic exposure decreased expression of the AP1 gene by a factor of 0.872 (0.803-0.940 95% C.I.) and the LFY gene by a factor of 0.471 (0.306-0.687 95% C.I.). The 15 Gy acute exposure decreased the expression of the AP1 gene by a factor of 0.104 (0.074-0.144 95% C.I.) and the PCNA2 gene by a factor of 0.346 (0.238-0.488 95% C.I.). Conclusions: The increased expression of the CO gene and decreased expression of the AP1 and FT genes under the lower dose of chronic exposure were associated with earlier flowering. The acute exposure increased the expression of the PCNA2 gene and decreased the expression of the flowering genes, except AP1. The flowering was delayed under both the higher dose of chronic exposure and under acute exposure, but it was less affected by the latter. Presumably, it was related to the activation of DNA repair under the 3 cGy chronic and 15 Gy acute irradiations.
... This inhibitory effect is primarily due to the accumulation of Na + and Clin reproductive organs [61]. Salinity strongly inhibits the formation of reproductive organs in Arabidopsis thaliana [65], decreases the fertility of Sorghum bicolor [66], and reduces pollen tube growth in grapevine styles [23], thereby reducing seed number [67]. Reproduction drastically decreases in Arabidopsis plants treated with 200 mM NaCl for only 12 h, with a very low percentage of seed formation (5% of ovules) [68]. ...
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Background: Halophytes show optimal reproduction under high-salinity conditions. However, the role of NaCl in reproduction and its possible mechanisms in the euhalophyte Suaeda salsa remain to be elucidated. Results: We performed transcript profiling of S. salsa flowers and measured starch accumulation in ovules, sugar contents in flowers, and photosynthetic parameters in the leaves of plants supplied with 0 and 200 mM NaCl. Starch accumulation in ovules, sugar contents in flowers and ovules, and net photosynthetic rate and photochemical efficiency in leaves were significantly higher in NaCl-treated plants vs. the control. We identified 14,348 differentially expressed genes in flowers of NaCl-treated vs. control plants. Many of these genes were predicted to be associated with photosynthesis, carbon utilization, and sugar and starch metabolism. These genes are crucial for maintaining photosystem structure, regulating electron transport, and improving photosynthetic efficiency in NaCl-treated plants. In addition, genes encoding fructokinase and sucrose phosphate synthase were upregulated in flowers of NaCl-treated plants. Conclusions: The higher starch and sugar contents in the ovules and flowers of S. salsa in response to NaCl treatment are likely due to the upregulation of genes involved in photosynthesis and carbohydrate metabolism, which increase photosynthetic efficiency and accumulation of photosynthetic products under these conditions.
... The experimental unit was plastic pot -free draining and sealed base. Free-draining pots contained gravel at the bottom and 3.5 kg mixed sand and soil collected from Mukinbudin (30°78 0 S, 118°31 0 E), Western Australia (Kotula et al., 2015) (1:1) at the top. The soil and sand were dried for 3 days at 65°C, passed through a 0.5-mm diameter sieve and mixed thoroughly before pot filling. ...
... Nevertheless, NaNO 3 priming alleviated the salinity effect and promoted a reduced K + /Na + content ratio in the roots by reducing the K + content as well as saltresistant species (Fig 8c, e). Therefore, the action of effective priming treatments such as NaNO 3 reaffirms that salinity tolerance is related not only to the presence of higher levels of Na + in the tissue but also to the tolerance of the tissue itself, as highlighted by Khan et al. (2015) and Kotula et al. (2015). ...
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Castor bean (Ricinus communis L.) cultivation requires production techniques appropriate for its growth conditions. Thus, the characterization of the deleterious effects of salinity on seed germination and on seedling establishment and the evaluation of the use of priming techniques on seeds could reduce replanting costs and improve emergence uniformity, preparing plant responses to salt stress. The goals of this current research were to characterize the deleterious effects of salinity on seed germination and on seedling establishment and to evaluate the use of the seed priming techniques as a tool to minimize these deleterious effect. In this research, castor bean seeds, cv. BRS-Energia was used to characterize effects of salt stress on germination and seedling establishment. Then, some chemicals such as PEG-6000 and H2O2 were evaluated to find the beneficial priming techniques for castor bean seeds against salt stress. Our results indicate that water imbibition by the seed under salinity conditions decelerated the time of exposure to salinity. Salinity also affected the germination of castor bean seeds under an Φs of -0.4 MPa and seedling growth was already affected under an Φs of -0.16 MPa. Priming with CaCl2, NaNO2, NaNO3 and PEG-6000 showed promising results under an Φs of 0.0 MPa, but priming with NaNO3 and PEG-6000 were ones that contributed most to better germination and establishment of seedlings under saline conditions. However, NaNO3 is the most recommended priming agent for castor bean because accelerated seed germination, reducing the time to emergence and planting risks.
... The experimental unit was plastic pot-free draining with a sealed base. Free-draining pots contained gravel at the bottom and 3.5 kg mixed sand and soil collected from Mukinbudin (30°78′ S, 118°31′ E), Western Australia (Kotula et al., 2015;1:1) at the top. ...
Article
Waterlogging causes germination failure in pea (Pisum sativum L.). Three genotypes (BM‐3, NL‐2 and Kaspa) contrasting in ability to germinate in waterlogged soil were exposed to different durations of waterlogging. Whole genome RNAseq was employed to capture differentially expressing genes. The ability to germinate in waterlogged soil was associated with testa colour and testa membrane integrity as confirmed by electrical conductivity measurements. Genotypes Kaspa and NL‐2 displayed different mechanisms of tolerance. In Kaspa, an energy conserving strategy was indicated by a strong upregulation of tyrosine protein kinsase and down regulation of LOX5, a fat metabolism gene. In contrast, a faster energy utilisation strategy was suggested in NL‐2 by the marked upregulation of a subtilase family protein and PNC2, a fat metabolising gene. Waterlogging susceptibility in germinating seeds of genotype BM‐3 was linked to upregulation of a kunitz‐type trypsin/protease inhibitor that blocks protein metabolism and may lead to excessive lipid metabolism and the membrane leakage associated with waterlogging damage. Pathway analyses based on gene ontologies showed seed storage protein metabolism as upregulated in tolerant genotypes and downregulated in the sensitive genotype. Understanding the tolerance mechanism provides a platform to breed for adaptation to waterlogging stress at germination in pea.
... Further, the delay in flowering was much shorter in tolerant genotypes than sensitive one, and this difference in the delay of flowering may be cause of the higher reproductive failure of the sensitive genotypes in the late sown condition (Turner et al. 2013). Consequently, salinity tolerance was not associated with the accumulation of Na and Cl ions in seeds at maturity and in leaves (Kotula et al. 2015). Salinity tolerance is a complex trait that involves a multitude of physiological and biochemical responses by inducing multiple genes upon exposure to salt stress (Wu et al. 2013). ...
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The growth of chickpea (Cicer arietinum L.) is extremely hampered by salt stress. Understanding of physio-biochemical and molecular attributes along with morphological traits contributing to the salinity tolerance is important for developing salt tolerant chickpea varieties. To explore these facts, two genotypes CSG8962 and HC5 with contrasting salt tolerance were evaluated in the salinity stress (Control and 120 mM NaCl) conditions. CSG8962 maintained lower Na/K ratio in root and shoot, trammeled Na translocation to the shoots from roots compared to HC5 which ascribed to better exclusion of salt from its roots and compartmentation in the shoot. In chickpea, salt stress specifically induced genes/sequences involved at several levels in the salt stress signaling pathway. Higher induction of trehalose 6 phosphate synthase and protein kinase genes pertaining to the osmotic and signaling modules, respectively, were evident in CSG8962 compared to HC5. Further transcripts of late embryogenesis abundant, non-specific lipid transfer protein, HI and 219 genes/sequences were also highly induced in CSG8962 compared to HC5 which emphasizes the better protection of cellular membranous network and membrane-bound macromolecules under salt stress. This further suppressed the stress enhanced electrolyte leakage, loss of turgidity, promoted the higher compatible solute accumulation and maintained better cellular ion homoeostasis in CSG8962 compared to HC5. Our study further adds to the importance of these genes in salt tolerance by comparing their behavior in contrasting chickpea genotypes.
... The leguminous crops are a rich source of proteins (Jukanti et al. 2012). Most of the leguminous crops are susceptible to salt stress and decrease their biomass and yield under saline conditions (Kotula et al. 2015). Therefore, the development of salinity-resistant leguminous crops has always remained an attractive target. ...
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The salinity stress causes a major threat for plant growth, yield, and biomass production. The present study was designed to assess the effect of exogenously applied kinetin and halotolerant plant growth-promoting rhizobacteria (H-PGPR) on alleviation of salt stress in black gram (Phaseolus mungo). A total of 15 rhizobacterial isolates obtained from a salt-affected area were analyzed for their capability to improve growth of P. mungo plants growing in greenhouse conditions. Out of the tested rhizobacteria, the two bacterial isolates which exhibited maximum growth potential were screened and their growth-promoting attributes were evaluated. The role of screened H-PGPR and/or kinetin (8 and 10 μM) was evaluated in P. mungo plants irrigated with three levels of brackish water (S1 = 3, S2 = 5, and S3 = 7 dSm⁻¹) under field condition. Salt stress reduced transpiration rate, stomatal conductance, salt tolerance index, growth, leaf area, photosynthetic pigments, leaf relative water content (LRWC), biomass production, and seed yield in subjected plants. Conversely, the salinized plants treated with kinetin and/or H-PGPR exhibited improved levels of chlorophyll contents, LRWC, root growth, shoot growth, biomass production, and seed yield. The H-PGPR and/or kinetin supplementation also reduced electrolyte leakage in salt-stressed plants. Overall, the present findings will be of great value to recognize the mechanism of salt stress alleviation in P. mungo plants under the influence of H-PGPR and/or kinetin.
... The experimental unit was plastic pot -free draining and sealed base. Free-draining pots contained gravel at the bottom and 3.5 kg mixed sand and soil collected from Mukinbudin (30°78 0 S, 118°31 0 E), Western Australia (Kotula et al., 2015) (1:1) at the top. The soil and sand were dried for 3 days at 65°C, passed through a 0.5-mm diameter sieve and mixed thoroughly before pot filling. ...
Article
Peas (Pisum sativum L.) are exposed to waterlogging at germination when grown as relay in rice-based cropping. Ninety-one germplasm accessions were evaluated in relay (sown in waterlogged soil), and subsequently 10 diverse genotypes compared under relay and sole cropping (conventional tillage sowing) over two seasons in Bangladesh. Contrasting genotypes, BM-3, NL-2 and Kaspa, were further evaluated in three waterlogging treatments (drained control, 4 and 8 days waterlogging) in the glasshouse. Conspicuous variation in waterlogging tolerance at germination was observed in the field and confirmed under controlled conditions. In relay sowing in 2011, emergence of a few genotypes was affected by waterlogging. In 2012, emergence in relay was severely affected (12 plants/m2) compared to sole sowing (37 plants/m2). Among genotypes BM-3 had 6 plants/m2 emerge, which all subsequently died, in contrast to NL-2 in which emergence was 13 plants/m2 with all plants surviving. In the glasshouse, there was 14% emergence in BM-3, 40% in NL-2 and 55% in Kaspa after 8 days of waterlogging. Such marked differences in waterlogging tolerance at germination in the model pea are the first reported and illustrate prospects for selection to improve adaptation to relay sowing in South Asia.
... The physiological and genomic screening revealed that there was a wide range of genetic differences among and within the tolerant and sensitive genotypes for salinity tolerance. For example, cold was included in tolerant-1 and inhibited in tolerant-2 during gene profiling using microarray aquaporin genes for drought, salinity, and homology-based induction for salinity, heat, and environmental stress (Mantri et al., 2007;Kotula et al., 2015;Kaur et al., 2008). Several haplotypes and significant numbers of alleles associated with agronomic parameters in chickpeas have been uncovered using genomic resources (Varshney et al., 2019a). ...
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Epigenomics has become a significant research interest at a time when rapid environmental changes are occurring. Epigenetic mechanisms mainly result from systems like DNA methylation, histone modification, and RNA interference. Epigenetic mechanisms are gaining importance in classical genetics, developmental biology, molecular biology, cancer biology, epidemiology, and evolution. Epigenetic mechanisms play important role in the action and interaction of plant genes during development, and also have an impact on classical plant breeding programs, inclusive of novel variation, single plant heritability, hybrid vigor, plant-environment interactions, stress tolerance, and performance stability. The epigenetics and epigenomics may be significant for crop adaptability and pliability to ambient alterations, directing to the creation of stout climate-resilient elegant crop cultivars. In this review, we have summarized recent progress made in understanding the epigenetic mechanisms in plant responses to biotic and abiotic stresses and have also tried to provide the ways for the efficient utilization of epigenomic mechanisms in developing climate-resilient crop cultivars, especially in chickpea, and other legume crops.
... This inhibitory effect is primarily due to the accumulation of Na + and Clin reproductive organs [61]. Salinity strongly inhibits the formation of reproductive organs in Arabidopsis thaliana [65], decreases the fertility of Sorghum bicolor [66], and reduces pollen tube growth in grapevine styles [23], thereby reducing seed number [67]. ...
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Background: Halophytes show optimal reproduction under high-salinity conditions. However, the role of NaCl in reproduction and its possible mechanisms in the euhalophyte Suaeda salsa remain to be elucidated. Results: We performed transcript profiling of S. salsa flowers and measured starch accumulation in ovules, sugar contents in flowers, and photosynthetic parameters in the leaves of plants supplied with 0 and 200 mM NaCl. Starch accumulation in ovules, sugar contents in flowers and ovules, and net photosynthetic rate and photochemical efficiency in leaves were significantly higher in NaCl-treated plants vs. the control. We identified 14,348 differentially expressed genes in flowers of NaCl-treated vs. control plants. Many of these genes were predicted to be associated with photosynthesis, carbon utilization, and sugar and starch metabolism. These genes are crucial for maintaining photosystem structure, regulating electron transport, and improving photosynthetic efficiency in NaCl-treated plants. In addition, genes encoding fructokinase and sucrose phosphate synthase were upregulated in flowers of NaCl-treated plants. Conclusions: The higher starch and sugar contents in the ovules and flowers of S. salsa in response to NaCl treatment are likely due to the upregulation of genes involved in photosynthesis and carbohydrate metabolism, which increase photosynthetic efficiency and accumulation of photosynthetic products under these conditions.
... This inhibitory effect is primarily due to the accumulation of Na + and Cl − in reproductive organs [61]. Salinity strongly inhibits the formation of reproductive organs in Arabidopsis thaliana [65], decreases the fertility of Sorghum bicolor [66], and reduces pollen tube growth in grapevine styles [23], thereby reducing seed number [67]. Reproduction drastically decreases in Arabidopsis plants treated with 200 mM NaCl for only 12 h, with a very low percentage of seed formation (5% of ovules) [68]. ...
Article
Full-text available
Background: Halophytes show optimal reproduction under high-salinity conditions. However, the role of NaCl in reproduction and its possible mechanisms in the euhalophyte Suaeda salsa remain to be elucidated. Results: We performed transcript profiling of S. salsa flowers and measured starch accumulation in ovules, sugar contents in flowers, and photosynthetic parameters in the leaves of plants supplied with 0 and 200 mM NaCl. Starch accumulation in ovules, sugar contents in flowers and ovules, and net photosynthetic rate and photochemical efficiency in leaves were significantly higher in NaCl-treated plants vs. the control. We identified 14,348 differentially expressed genes in flowers of NaCl-treated vs. control plants. Many of these genes were predicted to be associated with photosynthesis, carbon utilization, and sugar and starch metabolism. These genes are crucial for maintaining photosystem structure, regulating electron transport, and improving photosynthetic efficiency in NaCl-treated plants. In addition, genes encoding fructokinase and sucrose phosphate synthase were upregulated in flowers of NaCl-treated plants. Conclusions: The higher starch and sugar contents in the ovules and flowers of S. salsa in response to NaCl treatment are likely due to the upregulation of genes involved in photosynthesis and carbohydrate metabolism, which increase photosynthetic efficiency and accumulation of photosynthetic products under these conditions.
... The growing media comprised red-brown sandy clay loam (Calcic Haploxeralf), which had been used for waterlogging studies in pea (Zaman et al., 2018) and grass pea (Wiraguna et al., 2020). The soil was collected from Mukinbudin (30 • 78 ′ S, 118 • 31 ′ E), Western Australia (Kotula et al., 2015), with soil pH (CaCl 2 ) of 7.8, electrical conductivity (EC) 0.64 dS m −1 , and 1:5 w/v soil/water organic carbon content of 0.26%. The soil was dried for 5 days at 65 • C and sieved to 2 mm diameter. ...
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Mungbean [ Vigna radiata (L.) Wilczek] and blackgram [ Vigna mungo (L.) Hepper] are important crops for smallholder farmers in tropical and subtropical regions. Production of both crops is affected by unexpected and increasingly frequent extreme precipitation events, which result in transient soil waterlogging. This study aimed to compare the waterlogging tolerance of mungbean and blackgram genotypes under the varying duration of waterlogging stress at germination and seedling stages. We evaluated the responses to different durations of transient waterlogging in a sandy clay loam under temperature-controlled glasshouse conditions. Waterlogging durations were 0, 1, 2, 3, 4, 5, 6, 7, and 8 days during germination and 0, 2, 4, 8, and 16 days during the seedling stage. We used two mungbean genotypes (green testa), Celera II-AU (small-seeded), and Jade-AU (large-seeded), contrasting in seed size and hypocotyl pigmentation, and a blackgram genotype (black testa), Onyx-AU. Waterlogging reduced soil redox potential, delayed or even prevented germination, decreased seedling establishment, and affected shoot and root development. In the seedlings waterlogged (WL) at 15 days after sowing (DAS), adventitious root formation and crown nodulation varied between the genotypes, and 16 days of waterlogging substantially reduced growth but did not result in plant death. Plants in soil with waterlogging for 8–16 days followed by drainage and sampling at 39 DAS had reduced shoot and root dry mass by 60–65% in mungbean and 40% in blackgram compared with continuously drained controls, due at least in part to fewer lateral roots. Soil plant analysis development (SPAD) chlorophyll content was also reduced. Onyx-AU, a blackgram genotype, was more tolerant to transient waterlogging than Jade-AU and Celera II-AU in both growth stages. Of the two mungbean genotypes, Celera II-AU had a greater seedling establishment than Jade-AU post waterlogging imposed at sowing. In contrast, Jade-AU had more plant biomass and greater recovery growth than Celera II-AU after waterlogging and recovery during the seedling stage. Both species were delayed in emergence in response to the shorter periods of transient waterlogging at germination, and with the longer waterlogging germination and emergence failed, whereas at the seedling stage both showed adaptation by the formation of adventitious roots.
... Black plastic pots (85 × 85 × 180 mm) were each fitted with a transparent plastic bag and soil (~0.7 kg) from Mukinbudin, Western Australia (30°78′S, 118°31′E). The soil was sieved to <2 mm particle size, contained 0.3 % organic carbon, with pH 8.2 and EC 589 µs cm −1 of 1:5 w/v soil:DI water (Kotula et al. 2015;Zaman et al. 2018). ...
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Legume seeds, when relay sown following rice, may suffer from soil waterlogging and the associated hypoxia or even anoxia. This study evaluated the tolerance of grain legume species, grass pea (three genotypes), lentil (two genotypes), faba bean (two genotypes) and field pea (one genotype), to soil waterlogging in a glasshouse, to anoxia and hypoxia in temperature-controlled room at germination and seedling stages. Changes in oxygen in the surface layers of soil, with time after waterlogging, were measured by microelectrode profiling. The soil profiling showed that soil oxygen declined and then stabilised by the fourth day after waterlogging and oxygen was not detected at 8 mm below the soil surface. Germination of seeds under waterlogging for up to 12 days and seedling survival after the soil was drained for up to 36 days, were measured in pot experiments. Seed germination and/or survival in anoxia (N2-flushed solutions) and hypoxia (1.0 and 2.5 kPa oxygen) were evaluated, and so were post-anoxia or post-hypoxia recoveries, all in comparison with aerated controls. Lentil had higher seedling emergence (55%) than the other species during soil waterlogging. However, lentil had lower seedling survival (9%) than grass pea (28%) during recovery following soil drainage. Grass pea seeds were more tolerant of anoxia and of hypoxia than the seeds of the three other species. In conclusion, grass pea, with higher percent germination and seedling survival during recovery, is more tolerant to waterlogging and subsequent soil drainage than the three other grain legume species. Grass pea was also more tolerant of hypoxia and of anoxia at the seed germination stage. These findings demonstrate the superior waterlogging tolerance of grass pea in relay sowing, as compared with the other grain legumes.
... Presently, there is no finite test benchmark in salinity studies of legumes. However, chickpea (25 to 60 mM NaCl) [43][44][45][46], soybean (50 to 150 mM NaCl) [47,48], common bean (30 to 100 mM NaCl) [30][31][32][33] and a basic mungbean salt test dose was previously reported at 50 and 75 mM NaCl [34]. We utilized 50 mM NaCl as our test dose threshold for mungbean salinity germination test according to Chung et al. (2016) [37]. ...
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Mungbean (Vigna radiata (L.) R. Wilzeck var. radiata) is a protein-rich short-duration legume that fits well as a rotation crop into major cereal production systems of East and South-East Asia. Salinity stress in arid areas affects mungbean, being more of a glycophyte than cereals. A significant portion of the global arable land is either salt or sodium affected. Thus, studies to understand and improve salt-stress tolerance are imminent. Here, we conducted a genome-wide association study (GWAS) to mine genomic loci underlying salt-stress tolerance during seed germination of mungbean. The World Vegetable Center (WorldVeg) mungbean minicore collection representing the diversity of mungbean germplasm was utilized as the study panel and variation for salt stress tolerance was found in this germplasm collection. The germplasm panel was classed into two agro-climatic groups and showed significant differences in their germination abilities under salt stress. A total of 5288 SNP markers obtained through genotyping-by-sequencing (GBS) were used to mine alleles associated with salt stress tolerance. Associated SNPs were identified on chromosomes 7 and 9. The associated region at chromosome 7 (position 2,696,072 to 2,809,200 bp) contains the gene Vradi07g01630, which was annotated as the ammonium transport protein (AMT). The associated region in chromosome 9 (position 19,390,227 bp to 20,321,817 bp) contained the genes Vradi09g09510 and Vradi09g09600, annotated as OsGrx_S16-glutaredoxin subgroup II and dnaJ domain proteins respectively. These proteins were reported to have functions related to salt-stress tolerance.
... Chickpea is especially susceptible to salt stress at the reproductive stage of development, (Kotula et al., 2015 ) with crop roots suffering (Tejera et al., 2006) leading to lower productivity (Singla and Garg, 2005; Sohrabi et al., 2008 ). Salinity stress cause a decrease in plant height, crop growth rate and total plant biomass respectively by 20, 15 and 28 % (Atieno et al., 2017). ...
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T he salinity of irrigation water is a serious problem facing crop plants in the Mediterranean region, where plants are exposed to high temperatures and severe shortage of water in the dry season. So, this study was carried out in order to test the effects of five different salinity levels of sodium chloride (0.0, 50, 100, 150, 200 and 300 mM) on seed germination and early seedling growth of Chickpea (Cicer arietinum L.). Fifty homogenous and cleaned seeds were germinated in Petri dishes inthree replicates. The salt stress decreased seed germination, the response of Chickpea (Cicer arietinum L.) to salt stress and water stress was evaluated at the germination stage. T he severe reduction in germination percentage and particularly germination speed with prolonged lag period by moderate salinity level at 100 mM NaCl, suggests that Chickpea (Cicer arietinum L.) is a salt-sensitive species during germination. Salinity reduced germination uniformity and germination synchrony and might delay start of germination but accelerates its termination with a consequent shortening of the time spread of germination. The recovery percentage was lo wer but speed of recovery was higher compared with the corresponding parameters of the control seeds. Recovery percentage was slightly improved with increasing in the concentration of NaCl.
... Non-halophytes are sensitive to salt stress [58][59][60]. In addition, salinity inhibits the reproduction of non-halophytes by decreasing fertility and reproductive organ formation [61,62]. Salt stress speci cally affects male gamete development, typically resulting in high levels of microspore abortion and the induction of male sterility [63,64]. ...
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Background: Anther development affects the reproduction of flowering plants. Halophyte Elaeagnus angustifolia can bear fruits when grown in saline soils. However, no fruits are born in non-saline soils. The possible reasons and differences in E. angustifolia under two conditions were elucidated. Results: We examined features including pollen vitality and germination, in situ pollen germination after natural and hand pollination, anthers after pollen release, and the transcriptome in anthers. No significant difference was observed in pollen vitality or stigma receptivity in E. angustifolia in non-saline vs. saline habitats. However, no pollen tubes were present in styles, and pollen grains were abundant in E. angustifolia anthers under non-saline conditions. Notably, many pollen tubes formed in styles of E. angustifolia after hand pollination in the non-saline habitat. And the differentially expressed genes in anthers from saline vs. non-saline habitats were mainly related to phytohormones, cell wall secondary thickening, transcription factors and ion transport. Conclusions: E. angustifolia fail to form fruits in non-saline habitats due to poor anther pollen release. The induction and coordinated upregulation of genes related to anther cell wall formation and JA biosynthesis likely contribute to anther dehiscence in E. angustifolia in saline habitats, whereas anther dehiscence is blocked in plants grown in non-saline habitats.
... Non-halophytes are sensitive to salt stress [58][59][60]. In addition, salinity inhibits the reproduction of non-halophytes by decreasing fertility and reproductive organ formation [61,62]. Salt stress speci cally affects male gamete development, typically resulting in high levels of microspore abortion and the induction of male sterility [63,64]. ...
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Background: Anther development affects the reproduction of flowering plants. Halophyte Elaeagnus angustifolia can bear fruits when grown in saline soils. However, no fruits are born in non-saline soils. The possible reasons and differences in E. angustifolia under two conditions were elucidated. Results: We examined features including pollen vitality and germination, in situ pollen germination after natural and hand pollination, anthers after pollen release, and the transcriptome in anthers. No significant difference was observed in pollen vitality or stigma receptivity in E. angustifolia in non-saline vs. saline habitats. However, no pollen tubes were present in styles, and pollen grains were abundant in E. angustifolia anthers under non-saline conditions. Notably, many pollen tubes formed in styles of E. angustifolia after hand pollination in the non-saline habitat. And the differentially expressed genes in anthers from saline vs. non-saline habitats were mainly related to phytohormones, cell wall secondary thickening, transcription factors and ion transport. Conclusions: E. angustifolia fail to form fruits in non-saline habitats due to poor anther pollen release. The induction and coordinated upregulation of genes related to anther cell wall formation and JA biosynthesis likely contribute to anther dehiscence in E. angustifolia in saline habitats, whereas anther dehiscence is blocked in plants grown in non-saline habitats.
... However, with increasing salinity and under the combined effect of salinity and drought, both of these parameters were influenced significantly. Similarly, Kotula et al. [47] noticed a 40% and 33% reduction in the MSI and RWC, respectively, due to salinity stress in comparison to the control in melon. Salinity-induced effects can serve as an essential indicator for water relations to quantify the salt tolerating ability of plants [48]. ...
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Salinity and drought stress, singly or in combination, are major environmental menaces. Jatropha curcas L. is a biodiesel plant that can tolerate long periods of drought. However, the growth performance and stress tolerance based on physical, chemical, and physiological attributes of this plant have not yet been studied. To address this question, J. curcas seedlings were grown in a completely randomized design in plastic pots filled with soil to evaluate the effects of salinity and drought stresses on growth, ionic composition, and physiological attributes. The experiment consisted of six treatments: control (without salinity and drought stress), salinity alone (7.5 dS m-1 , 15 dS m-1), drought, and a combination of salinity and drought (7.5 dS m-1 +Drought, 15 dS m-1 +Drought). Our results revealed that, compared with the control, both plant height (PH) and stem diameter (SD) were reduced by (83%, 80%, and 77%) and (69%, 56%, and 55%) under salinity and drought combination (15 dS m-1 +Drought) after three, six, and nine months, respectively. There was 93% more leaf Na + found in plants treated with 15 dS m-1 +Drought compared with the control. The highest significant average membrane stability index (MSI) and relative water content (RWC) values (81% and 85%, respectively) were found in the control. The MSI and RWC were not influenced by 7.5 dS m-1 and drought treatments and mostly contributed towards stress tolerance. Our findings imply that J. curcas is moderately tolerant to salinity and drought. The Na + toxicity and disturbance in K + : Na + ratio were the main contributing factors for limited growth and physiological attributes in this plant.
... However, with increasing salinity and under the combined effect of salinity and drought, both of these parameters were influenced significantly. Similarly, Kotula et al. [47] noticed a 40% and 33% reduction in the MSI and RWC, respectively, due to salinity stress in comparison to the control in melon. Salinity-induced effects can serve as an essential indicator for water relations to quantify the salt tolerating ability of plants [48]. ...
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Salinity and drought stress, singly or in combination, are major environmental menaces. Jatropha curcas L. is a biodiesel plant that can tolerate long periods of drought. However, the growth performance and stress tolerance based on physical, chemical, and physiological attributes of this plant have not yet been studied. To address this question, J. curcas seedlings were grown in a completely randomized design in plastic pots filled with soil to evaluate the effects of salinity and drought stresses on growth, ionic composition, and physiological attributes. The experiment consisted of six treatments: control (without salinity and drought stress), salinity alone (7.5 dS m-1, 15 dS m-1), drought, and a combination of salinity and drought (7.5 dS m-1+Drought, 15 dS m-1+Drought). Our results revealed that, compared with the control, both plant height (PH) and stem diameter (SD) were reduced by (83%, 80%, and 77%) and (69%, 56%, and 55%) under salinity and drought combination (15 dS m-1+Drought) after three, six, and nine months, respectively. There was 93% more leaf Na+ found in plants treated with 15 dS m-1+Drought compared with the control. The highest significant average membrane stability index (MSI) and relative water content (RWC) values (81% and 85%, respectively) were found in the control. The MSI and RWC were not influenced by 7.5 dS m-1 and drought treatments and mostly contributed towards stress tolerance. Our findings imply that J. curcas is moderately tolerant to salinity and drought. The Na+ toxicity and disturbance in K+: Na+ ratio were the main contributing factors for limited growth and physiological attributes in this plant.
... Flowering time plays a crucial role in crops' adaptations and yield stabilisations in response to environmental cues [14][15][16]. Physiological studies have shown that salinity delays flowering time and severely affects the pod filling stages [9,17]. Despite pollen viability, sensitive genotypes show a higher occurrence of empty pods and seed abortions [12,18,19]. ...
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... High salinity affects nearly 10% of soils and 50% of irrigated land in the world (Guo et al., 2015;Wang et al., 2015;Song et al., 2017). Furthermore, high salt environments can greatly inhibit seedling growth and yield in salt-sensitive crops (Munns et al., 2006;Kotula et al., 2015), while salt-tolerant (halophyte) plants grow well under the same conditions (Guo et al., 2018). Therefore, deciphering the mechanisms at play during salt tolerance displayed by halophytes will provide the molecular basis for a better utilization of saline-alkali soil. ...
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... Non-halophytes are sensitive to salt stress [58][59][60]. In addition, salinity inhibits the reproduction of non-halophytes by decreasing fertility and reproductive organ formation [61,62]. Salt stress speci cally affects male gamete development, typically resulting in high levels of microspore abortion and the induction of male sterility [63,64]. ...
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... This implied that stress-acclimatized microbiome was efficient in reducing the detrimental effects of salinity stress in plants. Alterations in MSI occur in plants due to different stress conditions indicating cell damage (Kotula et al. 2015). MSI of plants amended with acclimatized microbiome was relatively more than that of plants without bacterial amendment under stress conditions, suggestive of reduced cell damage. ...
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... Salinity stress also severely affects germination, growth, nodulation and yield of chickpea, however, the reproductive processes are considered the most salt sensitive. But the mechanism(s) how the salinity affects reproductive processes in chickpea yet not known (Kotula et al., 2015). ...
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Key message Sustaining yield gains of grain legume crops under growing salt-stressed conditions demands a thorough understanding of plant salinity response and more efficient breeding techniques that effectively integrate modern omics knowledge. Abstract Grain legume crops are important to global food security being an affordable source of dietary protein and essential mineral nutrients to human population, especially in the developing countries. The global productivity of grain legume crops is severely challenged by the salinity stress particularly in the face of changing climates coupled with injudicious use of irrigation water and improper agricultural land management. Plants adapt to sustain under salinity-challenged conditions through evoking complex molecular mechanisms. Elucidating the underlying complex mechanisms remains pivotal to our knowledge about plant salinity response. Improving salinity tolerance of plants demand enriching cultivated gene pool of grain legume crops through capitalizing on ‘adaptive traits’ that contribute to salinity stress tolerance. Here, we review the current progress in understanding the genetic makeup of salinity tolerance and highlight the role of germplasm resources and omics advances in improving salt tolerance of grain legumes. In parallel, scope of next generation phenotyping platforms that efficiently bridge the phenotyping–genotyping gap and latest research advances including epigenetics is also discussed in context to salt stress tolerance. Breeding salt-tolerant cultivars of grain legumes will require an integrated “omics-assisted” approach enabling accelerated improvement of salt-tolerance traits in crop breeding programs.
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Anther development affects the reproduction of flowering plants. Halophyte Elaeagnus angustifolia can bear fruits when grown in saline soils. However, no fruits are born in non-saline soils. The possible reasons and differences in E. angustifolia under two growing conditions were elucidated. We examined features including pollen viability and germination, in situ pollen germination after natural and hand pollination, anthers after pollen release, and the transcriptome in anthers. No significant difference was observed in pollen viability or stigma receptivity in E. angustifolia in non-saline vs. saline habitats. However, no pollen tubes were present in styles, and pollen grains were abundant in E. angustifolia anthers under non-saline conditions. Notably, many pollen tubes formed in styles of E. angustifolia after hand pollination in the non-saline habitat. The differentially expressed genes in anthers from saline vs. non-saline habitats were mainly related to phytohormone, cell wall secondary thickening, transcription factors and ion transport. E. angustifolia fail to form fruits in non-saline habitats due to poor anther pollen release. The induction and coordinated upregulation of genes related to anther cell wall formation and JA biosynthesis likely contribute to anther dehiscence in E. angustifolia in saline habitats, whereas anther dehiscence is blocked in plants grown in non-saline habitats.
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Chickpea production is seriously challenged by various biotic and abiotic stresses globally. Among the various abiotic stresses, drought, heat, salinity and cold stresses are the major factors that restrict sustainable global chickpea production. Considerable progress has been made in developing drought, heat, cold and salinity stress-tolerant chickpea genotypes through conventional breeding approaches in concert with advanced breeding methods. Concurrently, current progress of molecular marker technology and availability of high-density genetic maps allowed genetic dissection of various abiotic stresses through biparental QTL mapping approach in chickpea. Subsequently, release of draft chickpea genome sequences greatly enriched chickpea genomic repertoire that provided us great opportunity for exploring the novel genetic determinants/haplotypes controlling these stresses across the whole genome level through genome-wide association study (GWAS). In parallel, current efforts of re-sequencing of global chickpea germplasm hold great promise for exploring ‘haplotype assembly’ carrying allelic variations for various abiotic stresses. Likewise, rapid advances in functional genomic approaches have enabled in unfolding the candidate gene(s) underlying the QTLs controlling these abiotic stresses, providing novel insights into the key molecular players participating in the complex mechanisms to acclimatize chickpea against various abiotic stress stimuli. In this chapter, we cover the effects of various abiotic stresses in chickpea, scope of diverse gene pool enabling in tailoring abiotic stress-tolerant chickpea genotypes and the role of rapidly growing genomics and emerging phenomics approaches to measure precise spatio-temporal response of plant under abiotic stresses for bridging genotyping and phenotyping gap. Finally, we conclude the chapter by discussing feasibility and scope of novel breeding techniques including genomic selection, ‘speed breeding’ and genome editing tool that could help in accelerating desired genetic gain to ensure protein-based nutritional food security under the fluctuating global climate scenario.
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Vegetable growth of halophytes has significantly increased through moderate salinity. However, little is known about the reproductive traits of euhalophytes. Male reproduction is pivotal for fertilization and seed production and sensitive to abiotic stressors. The pollen viability and pollen longevity of Suaeda salsa treated with 0 and 200 mM of NaCl were evaluated. It was revealed that the pollen size of S. salsa treated with NaCl was significantly bigger than that in controls. Furthermore, the pollen viability of S. salsa plants treated with NaCl was also significantly higher than that of control after 8 h of the pollens were collected (from 10 to 27 h). The pollen viability of NaCl-treated plants in the field could be maintained for 8 h (from 07:00 to 15:00) in sunny days, which was 1 h longer than that of control plants (from 07:00 to 14:00). Meanwhile, the pollen preservation time of NaCl-treated plants was 16 h at room temperature, which was 8 h longer than that of control plants. Genes related to pollen development, such as SsPRK3, SsPRK4, and SsLRX, exhibited high expression in the flowers of NaCl-treated plants. This indicated that NaCl markedly improved the pollen viability and preservation time via the increased expression of pollen development-related genes, and this benefits the population establishment of halophytes such as S. salsa in saline regions.
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Two chickpea varieties, differing in drought tolerance, were grown in lysimeters filled with clay, and were irrigated with waters of three different salinity levels. Under non-saline conditions, both varieties, slightly differing in pre-dawn leaf water potential during the growth period, gave almost the same yield. Salinity had a slight effect on the leaf water potential and the osmotic adjustment. Both were slightly higher for the drought tolerant variety, but much lower in comparison with sugar beet, tomato and lentil. The drought tolerant variety showed an earlier senescence in leaf and dry matter development and flowering which were accelerated by salinity. The drought sensitive variety, however, showed under slightly saline conditions (ECe = 2.5 dS/m) from 135 days after sowing onwards a different behaviour by the growth of new leaves and flowers, a delay in senescence, leading to the same yield as under non-saline conditions. Under saline conditions (ECe = 3.8 dS/m) the drought sensitive variety showed the same yield reduction of about 70% as the drought tolerant variety.
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With its low detection limits and the ability to analyze most of the elements in the periodic table, secondary ion mass spectrometry (SIMS) represents one of the most versatile in situ analytical techniques available, and recent developments have resulted in significant advantages for the use of imaging mass spectrometry in biological and biomedical research. Increases in spatial resolution and sensitivity allow detailed interrogation of samples at relevant scales and chemical concentrations. Advances in dynamic SIMS, specifically with the advent of NanoSIMS, now allow the tracking of stable isotopes within biological systems at subcellular length scales, while static SIMS combines subcellular imaging with molecular identification. In this chapter, we present an introduction to the SIMS technique, with particular reference to NanoSIMS, and discuss its application in biological and biomedical research.
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The effect of short-term treatments (10 days) by a high salt level (150mm NaCl) on vegetative and reproductive development was investigated in tomato plants (Solanum lycopersicum L. cv. Ailsa Craig) at two developmental stages. Salinity applied during flowering transition reduced shoot biomass and delayed the appearance of the first inflorescence. Both shoot and root biomasses were reduced when salt was applied during the development of the first inflorescence. At both stages, areas of young leaves decreased and time to first anthesis increased, while total number of flowers in the first inflorescence was not affected. Flower abortion, reduction of pollen number and viability were higher when salinity was applied during inflorescence development. Na + accumulated in all organs while K + decreased. Laser ablation inductively coupled plasma mass spectrometry microanalysis revealed that Na + accumulated in style, ovaries and anther intermediate layers but not in the tapetum nor in the pollen grains when salinity was applied during inflorescence development. K + was not significantly affected in these structures. Soluble carbohydrates dramatically increased in leaves and decreased in the inflorescence under salt stress conditions. The failure of inflorescence to develop normally under salt stress can be better explained in terms of altered source-sink relationships rather than accumulation of toxic ions.
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Aims Chickpea (Cicer arietinum L.) is considered a salt sensitive species, but some genetic variation for salinity tolerance exists. The present study was initiated to determine the degree of salt tolerance among chickpea genotypes, and the relationship between salt tolerance and ion accumulation in leaves and reproductive tissues. Methods Three experiments were conducted in a glasshouse in Perth, Western Australia, in which up to 55 genotypes of chickpea were subjected to 0, 40 or 60 mM NaCl added to the soil to determine the variation in salt tolerance, and the association between salt tolerance and reproductive success. Pod and seed numbers, seed yield and yield components, pollen viability, in vitro pollen germination and in vivo pollen tube growth, were used to evaluate reproductive success. Leaves, flowers and seeds were sampled in the reproductive phase to measure the concentrations of sodium, potassium and chloride ions in these organs. Results When grown in soil with 40 mM NaCl, a 27-fold range in seed yield was observed among the 55 chickpea genotypes. The increased salt tolerance, as measured by yield under salinity or relative yield under saline conditions, was positively associated with higher pod and seed numbers, and higher shoot biomass, but not with time to 50 % flowering nor with the number of filled pods in the non-saline treatment. Pod abortion was higher in the salt sensitive genotypes, but pollen viability, in vitro pollen germination and in vivo pollen tube growth were not affected by salinity in either the salt tolerant or salt sensitive genotypes. The concentrations of sodium and potassium ions, but not chloride, in the seed were significantly higher in the sensitive (106 μmol g−1 DM of sodium and 364 μmol g−1 DM of potassium) than in the tolerant (74 and 303 μmol g−1 DM, respectively) genotypes. Sodium and potassium, but particularly chloride, ions accumulated in leaves and in pod wall, whereas accumulation in the seed was much lower. Conclusions Considerable genotypic variation for salt tolerance exists in chickpea germplasm. Selection for genotypes with high pod and/or seed numbers that accumulate low concentrations of salt in the seed will be beneficial.
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SummaryA model system using dextran droplets of different salt solutions either frozen together, or sandwiched together after freezing and then freeze-substituted, embedded and dry sectioned has been investigated by X-ray microanalysis. X-ray maps and spot measur ements taken in transects through the interface of both droplets have shown that the P, K and Ca remain well localized in their original droplet. This validates freeze-substitution as a method for localization of these elements in biological samples. Results with Na were more variable and not always explainable. Success was achieved by the use of super-dry solvents and maintenance of a dry environment at all stages. We emphasize the need to avoid water contamination not only during freeze-substitution but also during sectioning, storage and section transfer to the electron microscope.
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An understanding of the mineral nutrition of plants is of fundamental importance in both basic and applied plant sciences. The Second Edition of this book retains the aim of the first in presenting the principles of mineral nutrition in the light of current advances. This volume retains the structure of the first edition, being divided into two parts: Nutritional Physiology and Soil-Plant Relationships. In Part I, more emphasis has been placed on root-shoot interactions, stress physiology, water relations, and functions of micronutrients. In view of the worldwide increasing interest in plant-soil interactions, Part II has been considerably altered and extended, particularly on the effects of external and interal factors on root growth and chapter 15 on the root-soil interface. The second edition will be invaluable to both advanced students and researchers.
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Summary To assess the potential for developing a salt resistant cultivar of chickpea (Cicer arietinum L.) 160 genotypes were screened for percent survival after 9 weeks in greenhouse solution cultures, with 50 mM NaCl or 25 mM Na2SO4. All plants grew well in the sulfate treatment but only cv. L-550 survived the chloride treatment. Salt damage appeared and developed slowly. To check these apparent effects of cultivar and kind of anion, three genotypes including cv. L-550 were then grown in solutions with isoosmotic NaCl or Na2SO4 at three levels (−0.044, −0.088, and −0.132 MPa), and in a separate experiment cv. L-550 was grown with NaCl and Na2SO4 at four levels: 10, 20, 30 and 50 mM Na. Salt composition affected shoot weight less than salt level or cultivar did. Shoot dry weight was only slightly less in chloride treatments than in isoosmotic sulfate, and for the least sensitive cultivar (L-550) this held only at the highest salt level, corresponding to that in the screening trial. Further, sensitivity to sulfate and to chloride was equal when sodium concentrations in shoots were equal, regardless of anion compositions of media. Shoot Na concentration was a useful negative indicator of growth under salt stress regardles of cultivar, and may be a useful tolerance indicator also for other species that neither accumulate nor efficiently exclude Na.
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In order to achieve reliable and reproducible analysis of biological materials by SIMS it is critical both that the chosen specimen preparation method does not modify substantially the in-vivo chemistry that is the focus of the study and that any chemical information obtained can be calibrated accurately by selection of appropriate standards. In Oxford we have been working with our new Cameca NanoSIMS50 on two very distinct classes of biological materials; the first where the sample preparation problems are relatively undemanding - human hair - but calibration for trace metal analysis is a critical issue, and the second - marine coccoliths and hyperaccumulator plants - where reliable specimen preparation by rapid freezing and controlled drying to preserve the distribution of diffusible species is the first and most demanding requirement, but worthwhile experiments on tracking key elements can still be undertaken even when it is clear that some redistribution of the most diffusible ions has occurred.
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Salinity is a major problem worldwide and improving salt tolerance of chickpea (Cicer arietinum L.) will allow expansion of production to more marginal areas. Plant reproduction suffers under salt stress in chickpea, but it remains unclear which process is most affected and what traits discriminate tolerant from sensitive lines. Three pot experiments were carried out to compare the effects of salt application (17 g NaCl kg−1 Alfisol) at sowing (SS) and at the start of flowering (SF) on growth, canopy transpiration, plant architecture, and flower, pod and seed development (timing, numbers, mass, abortion). Six pairs of tolerant/sensitive lines with similar flowering times within each pair, but different among the pairs, were used. Shoot biomass was similar in tolerant and sensitive lines in the SS and SF treatments, whereas the seed yield decreased more under SS and SF treatments in the sensitive lines. The flower, pod and seed numbers within all pairs was higher in the tolerant than in the sensitive lines in the non-saline controls, but the differences in numbers of seeds and pods further increased in both the SS and SF treatments. By contrast, neither the duration of flowering or podding, nor the percentage of flower or pod abortion, discriminated tolerant from sensitive lines. In non-saline controls the numbers of primary branches was 100% higher across the sensitive lines, whereas the number of tertiary branches was 8-fold higher across tolerant lines. The relative transpiration of the tolerant lines in the salt treatments was above that for the sensitive lines in three pairs of tolerant/sensitive lines, but did not differ within two pairs. Our results demonstrate that constitutive traits, i.e. numbers of flowers and tertiary branches, and adaptive traits, i.e. high number of seeds under salt stress, are both critical aspects of salinity tolerance in chickpea.
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Salinity is an ever-increasing problem in agriculture worldwide, especially in South Asia (India, Pakistan) and Australia. Improved genotypes that are well adapted to saline conditions are needed to enhance and sustain production in these areas. A screening of 263 accessions of chickpea, including 211 accessions from ICRISAT's mini-core collection (10% of the core collection and 1% of the entire collection), showed a 6-fold range of variation for seed yield under salinity (1.9L of 80mM NaCl per 7.5kg Vertisol), with several genotypes yielding 20% more than a previously released salinity tolerant cultivar. The range of variation in yields under salinity was similar in both kabuli and desi chickpeas, indicating that breeding for salinity tolerance can be undertaken in both groups. A strong relationship (r2=0.50) was found between the seed yield under salinity and the seed yield under a non-saline control treatment, indicating that the seed yield under salinity was explained in part by a yield potential component and in part by salinity tolerance per se. Seed yields under salinity were therefore computed to separate the yield potential component from the residuals that accounted for salinity tolerance per se. Among the genotypes evaluated, desi genotypes had higher salinity tolerance than kabuli genotypes. The residuals were highly correlated to the ratio of seed yield under salinity to that of the control, indicating that both parameters can be used to assess salinity tolerance. A similar ratio was calculated for shoot dry weight at 50 days after sowing. However, no significant correlation was found between the shoot dry weight ratio and the yield ratio, indicating that differences in salinity tolerance among genotypes could not be inferred from measurements in the vegetative stage. The major trait related to salinity tolerance was the ability to maintain a large number of filled pods, whereas seed size was similar in tolerant and sensitive genotypes. Salinity tolerance was not related to the shoot Na+ or K+ concentrations.
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Chickpea is the most important pulse crop of the arid and semi-arid areas. In India, it is cultivated during winter, depending on soil moisture stored from the preceding summer rain, which is often inadequate to ensure a satisfactory crop. In most such areas, saline ground water is the only source of supplementary irrigation to