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1.
Salinity primarily affects plants by inhibiting shoot growth. Salt‐sensitive plants have been suggested to accumulate Na+ within their leaf apoplast under salinity, leading to a reduced water status. Evidence related to apoplastic Na+ accumulation is still enigmatic. We have focused on the effect of a short‐term salt treatment by using the salt‐sensitive Vicia faba. Moreover, we have examined the role of silicon in alleviating sodium accumulation in the apoplast. Salt‐sensitive field beans have been subjected to increasing levels of salinity, with and without the addition of silicon under hydroponic conditions. We have demonstrated that the dicot Vicia faba exhibits a rise in Na+ concentration in the leaf apoplast at higher salinity levels; this is significantly ameliorated by the addition of silicon. Further, enhanced shoot growth under high salt treatment in the presence of added silicon is correlated with a significant decrease in Na+ concentration in the leaves. The novelty of the current study is the detection of a high Na+ concentration in the leaf apoplast of the salt‐sensitive dicot field bean. Our results support Oertli's hypothesis that extracellular salt accumulation can lead to wilting leaves, plant growth reduction and cell death.  相似文献   

2.
Although many screening criteria have been suggested to distinguish between genotypes for their salt tolerance under controlled environmental conditions, there is a need to test these criteria in the field. Saline soils are often complex and, therefore, unlikely to show a simple relationship to controlled conditions. To address this deficit, different agronomic and physiological screening criteria for salt tolerance in wheat at different stages were examined under both field and controlled conditions. Four wheat genotypes differing in their salt‐tolerance levels were grown in salt‐affected soil at two different locations and also under greenhouse conditions. Dry weight and leaf area of the upper and lower two leaves of the main stem and total dry weight at Zadoks scale 47 were measured in plants grown under field conditions. The concentrations of Cl?, Na+, K+ and Ca2+ in the upper and lower two leaves of the main stem at Zadoks scale 47 and different yield components were measured in plants grown under both conditions. Our results indicate that measurements derived from the upper two leaves of the main stem were generally more effective as screening criteria than those from the lower two leaves. Correlation coefficients between grain yield and either dry weight or leaf area of the upper two leaves of the main stem indicated that dry weight is inferior to leaf area as a screening criterion under field conditions. Number of sterile spikelets per plant performed well under both conditions, whereas the number of spikelets per plant and 1000‐grain weight failed to distinguish the differences of salt‐tolerance levels among genotypes accurately. Weight and number of grains per plant and number of fertile spikes per plant were poor criteria under controlled conditions, but effective under field conditions. The maintenance of low Cl? and Na+ concentrations in the upper two leaves offered the best guide to salt tolerance under both conditions. Potassium concentration was a poor criterion compared with the selectivity of K+ over Na+, which was useful under both field and controlled conditions. Calcium concentration and Ca2+ over Na+ selectivity in the upper and/or lower two leaves of the main stem were also effective in ranking genotypes according to their salt tolerance under both field and controlled conditions. Therefore, we conclude that simple measurements of the upper two leaves of the main stem including a straightforward measurement of leaf area, visually estimating the number of sterile spikelets, and a quick, practical determination of Na+ and Ca2+ concentration constitute effective criteria to screen wheat genotypes for salt tolerance under both field and controlled conditions.  相似文献   

3.
Soil salinity is a major limitation to legume production in many areas of the world. The salinity sensitivity of soybean was studied to determine the effect of salinity on seed germination, shoot and root dry weights, and leaf mineral contents. Three soybean cultivars, Lee, Coquitt, and Clark 63, were planted in soils of different salinity levels. The electrical conductivity (EC) of the soils used in this experiment was 0.5 dS m?1. The soil salinity treatments were 0.5, 2.5 4.5, 6.5 and 8.5 dS m?1. Saline drainage water from a drainage canal with an EC of 15 dS m?1 was used to treat the soil samples in order to obtain the desired salinity levels. Germination percentages were recorded 10 days after planting. Shoot and root dry weights of 45‐day‐old plants were measured. Nutrient concentrations for Na+, K+, Ca2+, Mg2+ and Cl? were determined. Germination percentages were significantly reduced with increasing salinity levels. The cultivar Lee was less affected by salinity stress than Coquitt and Clark 63. At 8.5 dS m?1 a significant reduction in plant height was found in all three cultivars. However, Lee plants were taller than plants of the other two cultivars. Salinity stress induced a significant increase in leaf sodium (Na+) and chloride (Cl?) in all cultivars. However, the cultivar Lee maintained lower Na+ and Cl+ concentrations, a higher potassium (K+) concentration and a higher K+/Na+ ratio at higher salinity levels than Coquitt and Clark 63. Saline stress reduced the accumulation of K+, calcium (Ca2+) and magnesium (Mg2+) in the leaves of the cultivars studied. This study suggests that Lee is the most tolerant cultivar, and that there is a relationship between the salt tolerance of the cultivar and macronutrient accumulation in the leaves.  相似文献   

4.
Genetic relationships between salt tolerance and expression of various physiological traits during vegetative growth in tomato, Lycopersicon esculentum Mill., were investigated. Parental, F1, F2 and backcross progeny of a cross between a salt tolerant (PI174263) and a salt sensitive tomato cultivar (‘UCT5’) were evaluated in saline solutions with electrical conductivity of 0.5 (non-stress) and 20 dS/m (salt stress). Absolute growth, relative growth, tissue ion content, leaf solute potential and the rate of ethylene evolution were measured. Growth of both parents was reduced under salt stress; however, the reduction was significantly less in PI174263 than ‘UCT5’, suggesting greater salt tolerance of the former. Under salt stress, leaves of PI174263 accumulated significantly less Na+ and Cl? and more Ca2+ than leaves of ‘UCT5’. Across parental and progeny generations, growth under salt stress was positively correlated with leaf Ca2+ content and negatively correlated with leaf Na+ content. In contrast, no correlation was observed between growth and either leaf solute potential or the rate of ethylene evolution under salt stress. Generation means analysis indicated that under salt stress both absolute and relative growth and the Na+ and Ca2+ accumulations in the leaf were genetically controlled with additivity being the major genetic component. The results indicated that the inherent genetic capabilities of PI174263 to maintain high tissue Ca2+ levels and to exclude Na+ from the shoot were essential features underlying its adaptation to salt stress and that these features were highly heritable. Thus, tissue ion concentration may be a useful selection criterion when breeding for improved salt tolerance of tomato using progeny derived from PI174263.  相似文献   

5.
Salinity reduces crop yield by limiting water uptake and causing ion‐specific stress. Soybean [Glycine max (L.) Merr.] is sensitive to soil salinity. However, there is variability among soybean genotypes and wild relatives for salt tolerance, suggesting that genetic improvement may be possible. The objective of this study was to identify differences in salt tolerance based on ion accumulation in leaves, stems and roots among accessions of four Glycine species. Four NaCl treatments, 0, 50, 75 and 100 mm , were imposed on G. max, G. soja, G. tomentella and G. argyrea accessions with different levels of salinity tolerance. Tolerant genotypes had less leaf scorch and a greater capacity to prevent Na+ and Cl? transport from soil solution to stems and leaves than sensitive genotypes. Magnitude of leaf injury per unit increase in leaf Na+ or Cl? concentrations was lower in tolerant than in susceptible accessions. Also, plant injury was associated more with Na+ rather than with Cl? concentration in leaves. Salt‐tolerant accessions had greater leaf chlorophyll‐meter readings than sensitive genotypes at all NaCl concentrations. Glycine argyrea and G. tomentella accessions possessed higher salt tolerance than G. soja and G. max genotypes.  相似文献   

6.
Cowpea is widely cultivated in arid and semi‐arid regions of the world where salinity is a major environmental stress that limits crop productivity. The effects of moderate salinity on growth and photosynthesis were examined during the vegetative phase of two cowpea cultivars previously classified as salt‐tolerant (Pitiúba) and salt‐sensitive (TVu). Two salt treatments (0 and 75 mm NaCl) were applied to 10‐day‐old plants grown in nutrient solution for 24 days. Salt stress caused decreases (59 % in Pitiúba and 72 % in TVu) in biomass accumulation at the end of the experiment. Photosynthetic rates per unit leaf mass, but not per unit leaf area, were remarkably impaired, particularly in TVu. This response was unlikely to have resulted from stomatal or photochemical constraints. Differences in salt tolerance between cultivars were unrelated to (i) variant patterns of Cl? and K+ tissue concentration, (ii) contrasting leaf water relations, or (iii) changes in relative growth rate and net assimilation rate. The relative advantage of Pitiúba over TVu under salt stress was primarily associated with (i) restricted Na+ accumulation in leaves paralleling an absolute increase in Na+ concentration in roots at early stages of salt treatment and (ii) improved leaf area (resulting from a larger leaf area ratio coupled with a larger leaf mass fraction and larger specific leaf area) and photosynthetic rates per unit leaf mass. Overall, these responses would allow greater whole‐plant carbon gain, thus contributing to a better agronomic performance of salt‐tolerant cowpea cultivars in salinity‐prone regions.  相似文献   

7.
Screening sorghum genotypes for salinity tolerant biomass production   总被引：1，自引：0，他引：1  
Genetic improvement of salt tolerance is of high importance due to the extent and the constant increase in salt affected areas. Sorghum [Sorghum bicolor (L.) Moench] has been considered relatively more salt tolerant than maize and has the potential as a grain and fodder crop for salt affected areas. One hundred sorghum genotypes were screened for salinity tolerance in pots containing Alfisol and initially irrigated with a 250-mM NaCl solution in a randomized block design with three replications. Subsequently 46 selected genotypes were assessed in a second trial to confirm their responses to salinity. Substantial variation in shoot biomass ratio was identified among the genotypes. The performance of genotypes was consistent across experiments. Seven salinity tolerant and ten salinity sensitive genotypes are reported. Relative shoot lengths of seedlings were genetically correlated to the shoot biomass ratios at all stages of sampling though the relationships were not close enough to use the trait as a selection criterion. In general, the whole-plant tolerance to salinity resulted in reduced shoot Na+ concentration. The K+/Na+ and Ca2+/Na+ ratios were also positively related to tolerance but with a lesser r 2. Therefore, it is concluded that genotypic diversity exists for salt tolerance biomass production and that Na+ exclusion from the shoot may be a major mechanism involved in that tolerance.  相似文献   

8.
Four bread wheat genotypes differing in salt tolerance were selected to evaluate ion distribution and growth responses with increasing salinity. Salinity was applied when the leaf 4 was fully expanded. Sodium (Na+), potassium (K+) concentrations and K+/Na+ ratio in different tissues including root, leaf‐3 blade, flag leaf sheath and flag leaf blade at three salinity levels (0, 100 and 200 mm NaCl), and also the effects of salinity on growth rate, shoot biomass and grain yield were evaluated. Salt‐tolerant genotypes (Karchia‐65 and Roshan) showed higher growth rate, grain yield and shoot biomass than salt‐sensitive ones (Qods and Shiraz). Growth rate was reduced severely in the first period (1–10 days) after salt commencements. It seems after 20 days, the major effect of salinity on shoot biomass and grain yield was due to the osmotic effect of salt, not due to Na+‐specific effects within the plant. Grain yield loss in salt‐tolerant genotypes was due to the decline in grain size, but the grain yield loss in salt‐sensitive ones was due to decline in grain number. Salt‐tolerant genotypes sequestered higher amounts of Na+ concentration in root and flag leaf sheath and maintained lower Na+ concentration with higher K+/Na+ ratios in flag leaf blade. This ion partitioning may be contributing to the improved salt tolerance of genotypes.  相似文献   

9.
Soil salinity is a major constraint to the cultivation of horticultural crops. In the present study, potted trees of the pear variety Abbé Fetel, either with their own roots or grafted on different rootstocks, received irrigation water at two levels of salinity to: (i) evaluate the effect of the rootstock genotype on the vegetative growth; (ii) assess their differential ability to take up and partition sodium (Na+) and chloride (Cl−); (iii) verify the effect of salinity on the uptake of major cations (potassium, calcium and magnesium). Irrigation water at 5.0 dS m−1 only slightly reduced vegetative growth regardless the genotype used as rootstock, suggesting a relative degree tolerance of pear (Pyrus communis) to soil salinity, at least in the short term. Quince (Cydonia oblonga) and pear rootstock genotypes had a contrasting effect on the uptake of chloride and sodium and differed regarding their ability to exclude these ions from the foliage. Quinces significantly increased their uptake of sodium and chloride when irrigated with saline water, while pear roots adopted an ion exclusion strategy to avoid accumulation of Na+ and Cl−. Trees grafted on quinces accumulated a significant amount of Cl− in the leaves, but were able to store most absorbed Na+ in their roots, a mechanism that prevented xylem loading and transport to the leaves. No effect of salinity on the uptake of potassium (K+), calcium (Ca2+) and magnesium (Mg2+) was recorded; however, leaf potassium concentration was markedly lower when roots belonged to quince than to pear. The ability of pear genotypes to take up K+ occurred in control trees and was unaffected by saline treatment and might be related to the strategy adopted by pears to exclude Na+ due to a high selectivity K+/Na+.  相似文献   

10.
Forty-five accessions of sunflower collected from different countries were screened for salinity tolerance after 2 weeks growth in sand culture salinized with 150 meq l?1 of NaCl2+ CaCl2 (1:1 ratio equivalent wt. basis) in half strength Hoagland's nutrient solution. The results for plant biomass of 45 accessions show that there was considerable variation in salinity tolerance. In a further greenhouse experiment, the salinity tolerance of three tolerant (HO-1, Predovik, Euroflor) and two sensitive (SMH-24, 9UO-985) lines (selected on the basis of their performance in the seedling experiment) was assessed at the adult stage to evaluate the consistency of salinity tolerance at different growth stages. All three salt tolerant accessions produced significantly greater plant biomass, seed yield and seed oil content than the salt sensitive accessions. The tolerant accessions accumulated less Cl? and more K+ in the leaves under saline conditions compared with the salt sensitive accessions. The salt tolerant accessions also maintained relatively high leaf K:Na ratio and K+ versus Na+ selectivity. Although statistically nonsignificant, all three tolerant accessions had greater soluble carbohydrates, soluble proteins, total free amino acids and proline in the leaves than the sensitive accessions. A field trial conducted in a salt-affected field confirmed the greenhouse results of the selected accessions. This study shows that salinity tolerance of sunflower does not vary with stage of plant cycle, so selection for increased salt tolerance can be carried out at the initial growth stage. Secondly, it is found that there is great variation of salt tolerance in sunflower. Low uptake of Cl?, high uptake of K+, and maintenance of high K:Na ratios and K+ versus Na+ selectivity in the leaves and possibly the accumulation of organic osmotica such as soluble carbohydrates, soluble proteins, proline and free amino acids seem to be the important components of salt tolerance in sunflower.  相似文献   

11.
The aims of this study were to compare the physiological responses of krishum (Iris lactea Pall. var. chinensis Koidz) to neutral and alkaline salt stress and identify and examine the mechanisms involved in plant response to salt treatments. In this study, biomass, ion accumulation (Na+, K+, Ca2+, Mg2+), organic solute (proline) concentration, rate of membrane electrolyte leakage (REL) and antioxidase activities including those of superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6) and peroxidase (POD, EC 1.11.1.7) were investigated in krishum under different concentrations of NaCl, Na2CO3 and the mixture of the two salts in the same volume. All three treatments caused increases in Na+ concentration, proline content and REL and decreases in root Mg2+ and K+ content. Increased Ca2+ and antioxidase activities were observed at lower external Na+ concentrations. However, at higher external Na+ levels, decreased Ca2+ and antioxidase activities were detected. Alkaline salt resulted in more damage to krishum than neutral salt including lower SOD, POD and CAT activities and decreased proline content, relative to neutral salt. High Na+ and low K+ in krishum intensified ion toxicity under alkaline condition. Alkaline salt caused greater harm to plants than neutral salt, the primary reason of which might be the lower Ca2+ content in the plant under alkaline salt stress.  相似文献   

12.
Salinity and boron (B) toxicity often occur simultaneously and may have interactive effects on plant responses. This study aims at further investigating long‐term effects of salinity, B toxicity and their combination on wheat plants. Plants grown in hydroponics were treated with 2.5 μm H3BO3 (control), 75 mm NaCl, 200 μm H3BO3 or 75 mm NaCl + 200 μm H3BO3 and were analysed on a subcellular level 6 weeks after germination. Shoot fresh and dry weight (DW), water content, transpiration rate and osmolality were reduced, while Na+ and Cl? concentrations increased under salinity stress. However, Cl? was reduced in all compartments by an additional application of B toxicity. At adequate B supply, NaCl increased apoplastic and symplastic soluble B concentrations, whereas the total B content remained unchanged. At high B level, however, soluble and total B was reduced by additional salt stress. Despite this antagonistic effect of a combined salt and B toxicity stress on Cl? and B concentrations, an additive effect was observed regarding shoot fresh weight reduction. Our results confirm an alleviating effect of the combined stresses on toxic ion concentrations, which did not prevent additive growth reductions.  相似文献   

13.
Salinity is known to reduce chickpea yields in several regions of the world. Although ion toxicity associated with salinity leads to yield reductions in a number of other crops, its role in reducing yields in chickpea growing in saline soils is unclear. The purpose of this study was to (i) identify the phenological and yield parameters associated with salt stress tolerance and sensitivity in chickpea and (ii) identify any pattern of tissue ion accumulation that could relate to salt tolerance of chickpea exposed to saline soil in an outdoor pot experiment. Fourteen genotypes of chickpea (Cicer arietinum L.) were used to study yield parameters, of which eight were selected for ion analysis after being grown in soil treated with 0 and 80 mm NaCl. Salinity delayed flowering and the delay was greater in sensitive than tolerant genotypes under salt stress. Filled pod and seed numbers, but not seed size, were associated with seed yield in saline conditions, suggesting that salinity impaired reproductive success more in sensitive than tolerant lines. Of the various tissues measured for concentrations of Cl?, Na+ and K+, higher seed yields in saline conditions were positively correlated with higher K+ concentration in seeds at the mid‐filling stage (R2 = 0.55), a higher K+/Na+ ratio in the laminae of fully expanded young leaves (R2 = 0.50), a lower Na+ concentration in old green leaves (R2 = 0.50) and a higher Cl? concentration in mature seeds. The delay in flowering was associated with higher concentrations of Na+ in the laminae of fully expanded young leaves (R2 = 0.61) and old green leaves (R2 = 0.51). We conclude that although none of the ions appeared to have any toxic effect, Na+ accumulation in leaves was associated with delayed flowering that in turn could have played a role in the lower reproductive success in the sensitive lines.  相似文献   

14.
 以叶片衰老快慢不同的两个棉花品系L21和L22为材料,研究了NaCl胁迫对棉花叶片衰老的影响及其相应的生理学机制。温室内水培棉苗,待第5片真叶展开20 d后用含125 mmol·L-1 NaCl的营养液处理棉苗,以不含NaCl的营养液处理为对照。结果显示,NaCl胁迫下L21和L22叶片中叶绿素含量和光合作用速率下降,叶片和根中的Na+含量上升、K+含量降低;NaCl胁迫还增加了棉株体内脱落酸（ABA）含量、降低了玉米素核苷（ZR）含量。表明K+含量降低以及ABA含量升高、ZR含量下降是NaCl胁迫促进棉花叶片衰老的重要原因。  相似文献   

15.
We studied the effects of the rootstocks, Cleopatra mandarin and Carrizo citrange and of saline irrigation water (3, 15 and 30 mM NaCl) on yield, growth, fruit quality and leaf mineral composition of ‘Clemenules’ mandarin citrus trees. At the end of the experiment, ‘Clemenules’ trees grafted on Carrizo had higher yield efficiency (cumulative yield of three years per canopy volume) than trees grafted on Cleopatra, under both control and saline treatments. Fruit yield was reduced by the salinity due to a decrease in the number of fruit per tree but not fruit size. Trees on Cleopatra mandarin accumulated less Cl− and more Na+ than those grafted on Carrizo. The leaf Na+ concentration reached its maximum value during the first year; however, the leaf Cl− concentration continued increasing with time. For both rootstocks, leaf concentrations of N, P and K+ decreased with increasing salinity levels. Salinity reduced juice content and increased total soluble solids (TSS) in fruit from trees on Carrizo.  相似文献   

16.
A pot experiment was conducted in a climate‐controlled greenhouse to investigate the growth, physiology and yield of potato in response to salinity stress under biochar amendment. It was hypothesized that addition of biochar may improve plant growth and yield by mitigating the negative effect of salinity through its high sorption ability. From tuber bulking to harvesting, the plants were exposed to three saline irrigations, that is 0, 25 and 50 mm NaCl solutions, respectively, and two levels of biochar (0 % and 5 % W/W) treatments. An adsorption study was also conducted to study the Na+ adsorption capability of biochar. Results indicated that biochar was capable to ameliorate salinity stress by adsorbing Na+. Increasing salinity level resulted in significant reductions of shoot biomass, root length and volume, tuber yield, photosynthetic rate (An), stomatal conductance (gs), midday leaf water potential, but increased abscisic acid (ABA) concentration in both leaf and xylem sap. At each salinity level, incorporation of biochar increased shoot biomass, root length and volume, tuber yield, An, gs, midday leaf water potential, and decreased ABA concentration in the leaf and xylem sap as compared with the respective non‐biochar control. Decreased Na+, Na+/K+ ratio and increased K+ content in xylem with biochar amendment also indicated its ameliorative effects on potato plants in response to salinity stress. The results suggested that incorporation of biochar might be a promising approach for enhancing crop productivity in salt‐affected soils.  相似文献   

17.
Salt (NaCl)‐induced regulation of some key physio‐biochemical characteristics in two okra (Abelmoschus esculentus L.) cultivars (Nirali and Posa Sawni) was examined under greenhouse conditions. Plants of both cultivars were subjected for 30 days to sand culture salinized with four salt levels [0 (control), 50, 100 and 150 mm NaCl] in Hoagland’s nutrient solution. Salt stress significantly reduced the shoot and root fresh weights, transpiration rate, chlorophyll b content, net CO2 assimilation (A), transpiration rate (E), while enhanced leaf and root Na+ and Cl– concentrations in both cultivars. In contrast, chlorophyll a content, stomatal conductance (gs), leaf internal CO2 (Ci), Ci/Ca ratio, water‐use efficiency (A/E) and fluorescence characteristics such as photochemical quenching (qP), non‐photochemical quenching (NPQ), efficiency of PS‐II (Fv/Fm), proline contents, and leaf and root K+, Ca2 + and N contents remained almost unaffected in both lines due to salt stress. The efficiency of PSII (Fv/Fm), A, chlorophyll b, root fresh weight and root N were higher in relatively salt tolerant cv. Nirali, whereas leaf Na+ and root Cl– were higher in cv. Posa Sawni. The relatively more reduction in growth in the cv. Posa Sawni was found to be associated with higher accumulation of Na+ in its leaves and Cl– in roots.  相似文献   

18.
Salinity stress causes ion toxicity and osmotic imbalances, leading to oxidative stress in plants. Arbuscular mycorrhizae (AM) are considered bio‐ameliorators of saline soils and could develop salinity tolerance in crop plants. Pigeonpea exhibits strong mycorrhizal development and has a high mycorrhizal dependency. The role of AM in enhancing salt tolerance of pigeonpea in terms of shoot and root dry weights, phosphorus and nitrogen contents, K+ : Na+, Ca2+ : Na+ ratios, lipid peroxidation, compatible solutes (proline and glycine betaine) and antioxidant enzyme activities was examined. Plants were grown and maintained at three levels of salt (4, 6 and 8 dSm?1). Stress impeded the growth of plants, led to weight gain reductions in shoots as well as roots and hindered phosphorus and nitrogen uptake. However, salt‐stressed mycorrhizal plants produced greater root and shoot biomass, had higher phosphorus and nitrogen content than the corresponding uninoculated stressed plants. Salt stress resulted in higher lipid peroxidation and membrane stability was reduced in non‐AM plants. The presence of fungal endophyte significantly reduced lipid peroxidation and membrane damage caused by salt stress. AM plants maintained higher K+ : Na+ and Ca2+ : Na+ ratios than non‐AM plants under stressed and unstressed conditions. Salinity induced the accumulation of both proline and glycine betaine in AM and non‐AM plants. The quantum of increase in synthesis and accumulation of osmolytes was higher in mycorrhizal plants. Antioxidant enzyme activities increased significantly with salinity in both mycorrhizal and non‐mycorrhizal plants. In conclusion, pigeonpea plants responded to an increased ion influx in their cells by increasing the osmolyte synthesis and accumulation under salt stress, which further increased with AM inoculation and helped in maintaining the osmotic balance. Increase in the antioxidant enzyme activities in AM plants under salt stress could be involved in the beneficial effects of mycorrhizal colonization.  相似文献   

19.
Crop tolerance to salinity is of high importance due to the extent and the constant increase in salt-affected areas in arid and semi-arid regions. Pearl millet (Pennistum glaucum), generally considered as fairly tolerant to salinity, could be an alternative crop option for salt affected areas. To explore the genotypic variability of vegetative-stage salinity tolerance, 100 pearl millet lines from ICRISAT breeding programs were first screened in a pot culture containing Alfisol with 250 mM NaCl solution as basal application. Subsequently, 31 lines including many parents of commercial hybrids, selected from the first trial were re-tested for confirmation of the initial salinity responses. Substantial variation for salinity tolerance was found on the basis of shoot biomass ratio (shoot biomass under salinity/ non-saline control) and 22 lines with a wide range of tolerance varying from highly tolerant to sensitive entries were identified. The performance of the genotypes was largely consistent across experiments. In a separate seed germination and seedling growth study, the seed germination was found to be adversely affected (more than 70% decrease) in more than half of the genotypes with 250 mM concentration of NaCl. The root growth ratio (root growth under salinity/control) as well as shoot growth ratio was measured at 6 DAS and this did not reflect the whole plant performance at 39 DAS. In general, the whole plant salinity tolerance was associated with reduced shoot N content, increased K+ and Na+ contents. The K+/Na+ and Ca++/Na+ ratios were also positively related to the tolerance but not as closely as the Na+ content. Therefore, it is concluded that a large scope exists for improving salt tolerance in pearl millet and that shoot Na+ concentration could be considered as a potential non-destructive selection criterion for vegetative-stage screening. The usefulness of this criterion for salinity response with respect to grain and stover yield remains to be investigated.  相似文献   

20.
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