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1.
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   

2.
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   

3.
Na+ accumulation in the leaf apoplast has been suggested to lead to dehydration, later wilting and finally, the death of the affected leaves. Our aim has been to evaluate whether the reduction in the plant growth of sensitive maize in response to salinity is correlated with higher amounts of Na+ and Cl? concentrations in the leaf apoplast. Subcellular ion patterns in intact leaves were investigated by using deionised water infiltration. We found an increase in soluble Na+ and Cl? concentrations of about 16‐ and 4‐fold, respectively, compared with the control. These concentrations characterized the apoplasts of expanding leaves that had entirely developed under salinity. Interestingly, the K+ concentration was significantly reduced by 64 % compared with its control in the symplast under salinity. Our finding of a significantly decreased Ca2+ concentration in shoots suggested a possible association of Ca2+ concentration with the reduction in leaf expansion under salinity. As the absolute increase in the apoplastic Na+ concentration during salt treatment was much lower compared with the increase in the symplastic Na+ concentration, salt treatment in maize appears not to result in osmotic stress imposed by a high apoplastic Na+ concentration as has been suggested for other plant species (Oertli hypothesis).  相似文献   

4.
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   

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.
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   

7.
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   

8.
The response of cotton to constant salinity has been well documented under controlled conditions, but its response to changing salinity under field conditions is poorly understood. Using a split‐plot design, we conducted a 2‐year field experiment to determine the effects of soil salinity and plant density on plant biomass, boll load, harvest index and leaf senescence in relation to cotton yield in three fields with similar fertility but varying salinity. The main plots were assigned to weak (electrical conductivity of soil saturated paste extract, ECe = 5.5 dS m?1), moderate (ECe = 10.1 dS m?1) and strong (ECe = 15.0 dS m?1) soil salinity levels, while plant density (3.0, 4.5 and 7.5 plants m?2) was assigned to the subplots. Soil salinity had a negative effect on seedcotton yield, but the negative effect was compensated for by increased plant density under strong‐salinity conditions. Seedcotton yield under weak salinity changed little with varying plant density, but the medium plant density yielded better than the low or high plant density under moderate salinity. Plants accumulated 49 and 112 % more Na+ in leaves under moderate and strong salinity than under weak salinity. Strong salinity also led to higher boll load and early leaf senescence. Plant density had no effect on Na+ accumulation in leaves, but greatly reduced boll load and delayed leaf senescence. Plant biomass, maximum leaf area index and harvest index were greatly affected by salinity, plant density and their interaction. Accelerated leaf senescence under strong salinity was attributed to the high boll load and increased accumulation of toxic ions like Na+ in leaves, while delayed leaf senescence with increased plant density was attributed to the reduced boll load. Optimal yield can only be obtained with proper coordination of total biomass and harvest index by modification of plant density based on salinity levels.  相似文献   

9.
Soil salinity is often heterogeneous, yet plant response to unequal salt distribution (USD) in the root zone is seldom studied in cotton (Gossypium hirsutum L.). Our objective was to evaluate the effects of USD on growth and yield, as well as its potential application for increasing cotton production. To achieve this objective, greenhouse and field experiments were conducted. In the first experiment, potted cotton plants were grown in a split-root system in the greenhouse. Each root half was irrigated with either the same or two concentrations of NaCl. Plant biomass, leaf chlorophyll (Chl), photosynthesis (Pn) and transpiration (Tr), Na+ and K+ accumulation, as well as biological and economic yields were determined. In the second experiment, plants were grown in furrow-beds in saline fields with those grown on flat beds as controls. Root-zone salinity, yield and yield components and earliness (the percentage of the first two harvests to total harvests) were monitored. When the entire root system was exposed to the same concentration of NaCl, shoot dry weight, leaf area, plant biomass, leaf Chl, Pn and Tr were markedly reduced relative to the NaCl-free control at 2 weeks after salinity stress (WAS). Significant reductions in biological (23.6–73.8%) and economic yields (38.1–79.7%) were noticed at harvest. However, when only half of the root system was exposed to low-salinity, the inhibition effect of salinity on growth and yield was significantly reduced. Plant biomass and seed cotton yield were increased by 13 and 23.9% with 50/150 mM/mM NaCl, 40 and 44.5% with 100/300 mM/mM NaCl, and 85.7 and 127.8% with 100/500 mM/mM NaCl relative to their respective equal salt distribution (ESD) controls (100/100, 200/200, and 300/300). Unequal salt distribution also decreased concentrations of Na+ and increased leaf K+ and Chl content, K+/Na+ ratio, Pn and Tr, compared with ESD. Furrow-bed seeding induced unequal distribution of salts in the surface soil during the field experiment. Under furrow planting, soil salinity was much higher, but soil osmotic potential was much lower on the ridged part than the furrows. Yield and earliness were increased 20.8 and 5.1% by furrow seeding relative to flat seeding. These enhancements were mainly attributed to unequal distribution of salts in the root zone. Thus, specific cultural practices that induce unequal salt distribution such as furrow-bed seeding can be used to improve cotton production in saline fields.  相似文献   

10.
Soil salinity is a worldwide issue that affects agricultural production. The understanding of mechanisms by which plants tolerate salt stress is crucial for breeding varieties for salt tolerance. In this work, a large number of wheat (Triticum aestivum and Triticum turgidum) cultivars were screened using a broad range of physiological indices. A regression analysis was then used to evaluate the relative contribution of each of these traits towards the overall salinity tolerance. In general, most of the bread wheats showed better Na+ exclusion that was associated with higher relative yield. Leaf K+/Na+ ratio and leaf and xylem K+ contents were the major factors determining salinity stress tolerance in wheat. Other important traits included high xylem K+ content, high stomatal conductance and low osmolality. Bread wheat and durum wheat showed different tolerance mechanisms, with leaf K+/Na+ content in durum wheat making no significant contributions to salt tolerance, while the important traits were leaf and xylem K+ contents. These results indicate that Na+ sequestration ability is much stronger in durum compared with bread wheat, most likely as a compensation for its lesser efficiency to exclude Na+ from transport to the shoot. We also concluded that plant survival scores under high salt stress can be used in bread wheat as a preliminary selection for Na+ exclusion gene(s).  相似文献   

11.
黄河三角洲盐渍棉花施用氮、磷、钾肥的效应研究   总被引：7，自引：0，他引：7  
为探讨盐渍土抗虫棉施用NPK肥的效应及其营养生理机制,指导滨海盐渍土抗虫棉合理施肥,在黄河三角洲盐渍土低、中、高盐棉田种植转Bt基因抗虫棉鲁棉研28,研究N、P、K肥配合施用对其养分吸收利用、Na+吸收积累、光合速率、干物质积累和产量的影响。结果表明,N、P肥配合,尤其是N、P、K肥配合施用显著增加了低、中、高盐田棉花的N、P、K养分吸收量,减少了Na+吸收积累量。低、中、高盐田棉花的N、P、K养分农学利用效率均以NPK配施的处理较高,氮养分农学利用效率分别为0.20、1.95和2.07 kg皮棉 kg–1 N,磷养分农学利用效率分别为0.87、8.35和8.71 kg皮棉 kg–1 P,钾养分农学利用效率分别为0.26、2.89和3.77 kg皮棉 kg–1 K。N、P、K肥配合施用还维持了较高的棉株叶面积、叶绿素含量和净光合速率。低、中、高盐田棉花的生物产量和皮棉产量也均以NPK配施的处理较高,皮棉产量分别增产2.53%、28.67%和30.47%。中、高盐棉田的施肥效应明显好于低盐棉田。表明根据盐碱程度分类合理施肥是减轻盐渍土营养障碍、改善棉花营养、提高养分农学利用效率和棉花产量的有效途径。  相似文献   

12.
适用于低钾条件下棉花苗期根冠通讯研究的三种嫁接方法   总被引：2，自引：0，他引：2  
为了满足棉花叶片衰老(以缺钾诱导)过程中根冠通讯研究的需要, 在营养液培养条件下探索了棉花子叶期至一叶期幼苗的单接穗单砧木嫁接、双接穗单砧木(Y型)和单接穗双砧木(A型)嫁接技术。通过研究营养液中钾浓度、砧木和接穗的苗龄配合、嫁接部位及砧木保留子叶对嫁接成活率的影响, 综合考虑嫁接成活率和成活后用缺钾诱导嫁接苗衰老的速度, 确定接穗单砧木嫁接和Y型嫁接的砧木均在不含钾的沙床中出苗后(萌发后3 d)转移至钾浓度为0.1 mmol L-1(中度钾胁迫)的1/2改良Hoagland营养液中培养5 d至第1片真叶出现, 接穗在不含钾的沙床中出苗后(萌发后3 d)再生长2 d, 采用砧木留子叶法在子叶节处嫁接。A型嫁接的适宜条件和方法为砧木和接穗苗龄(第1片真叶刚出现)相同, 嫁接前的培养方法同Y型砧木, 嫁接部位在砧木子叶节下2~3 cm处。单接穗单砧木、Y型和A型嫁接的平均成活率分别可达到95%、85%和90%以上。  相似文献   

13.
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   

14.
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   

15.
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   

16.
Soil salinity is a notorious abiotic stress which constrains plant growth and limits crop productivity. Recent advances in phytogenetics especially the discovery of marker-trait association have facilitated the efficient selection of stress-tolerant crops. The objective of this study was to evaluate tall fescue (Festuca arundinacea Schreb.) accessions growing under salt stress in order to identify salt-tolerant and salt-sensitive genotypes using physiological and molecular markers. The population consisted of 114 diverse tall fescue accessions which were assessed using 99 simple sequence repeat (SSR) markers and five functional physiological traits i.e., turf quality, leaf water content, chlorophyll content, relative growth rate, and evapotranspiration rate. Salinity stress induced great variations among the functional physiological traits and there were significant correlations among them. The population structure analysis revealed two distinct populations, while association mapping between the SSRs and phenotypic traits identified significant associations. In addition, the accessions that maintained relatively higher physiological traits had a significantly lower accumulation of Na+ and Cl? in the roots compared to those whose functional traits declined. We identified six most salt-tolerant accessions due to their high values of physiological parameters and significantly low accumulation of Na+ and Cl? in the roots. Similarly, we identified six accessions we considered to be most salt-sensitive as observed by high Na+ and Cl? accumulation plus a decline in the physiological activities. Our findings are helpful to tall fescue breeders with a goal of producing tall fescue cultivars with enhanced salt tolerance.  相似文献   

17.
Summary Embryogenic calli isolated from immature embryos of four wheat cultivars were subjected to three in vitro selection methods for salt tolerance. The effect of NaCl on the selected and unselected cell lines has been investigated. The results indicated that the relative growth rate of callus decreased as the concentration of NaCl increased in both callus lines. The selected callus line gave a higher growth weight in the presence of NaCl in the medium and was highly significant as compared with unselected callus line across medium protocols in all wheat cultivars. The dry weight of both kinds of callus lines of all wheat cultivars increased markedly with increasing NaCl concentration in most cases. The Na+ and Cl- contents of both callus lines were increased with increasing salinity levels while K+ content was decreased. The selected callus line of each cultivar at the same salinity level produced significant amounts of Na+, K+ and Cl- higher than the unselected callus line in most salinity levels. However, the unselected callus lines of the cultivars Giza-157 and Sakha-90 at the same salinity level produced significant amounts of K+ higher than the selected callus line in most salinity levels. The proline content of both kinds of callus lines for all wheat cultivars was increased with increasing salinity level. However, the selected callus line gave a significantly higher proline content than the unselected callus line in all wheat cultivars at the same Salinity level. Results from the in vitro selection for NaCl tolerance showed that the stepwise method of increasing NaCl in the medium was more effective for plant regeneration than other methods.  相似文献   

18.
D. Zamir  M. Tal 《Euphytica》1987,36(1):187-191
Summary Plants of the salt-sensitiveL. esculentum, the halophytic wild speciesL. pennellii, their F1 hybrids and the interspecific F2 generation were grown in Hoagland's liquid culture containing 100 mM NaCl and 6 mM K+. Analysis of the Na+, Cl- and K+ ions contents of the leaves showed, as observed also in previous studies, that the cultivated parent accumlated more K+ and less Na+ than the wild parent. A total of 117 F2 plants were assayed for 15 electrophoretically detectable isozyme markers which map to nine of the twelve tomato chromosomes. Four loci, all with a similar quantitative effect on Na+ and Cl- uptake, were identified by virtue of their linkage to isozyme markers. Two other loci were found to affect K+ uptake. This study demonstrates the potential value of using genetic markers in order to gain a better understanding of the genetic basis of quantitative traits associated with the response of plants to salinity stress.  相似文献   

19.
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   

20.
Quinoa is recently introduced to Pakistan as a salt‐tolerant crop of high nutritional value. Open field trials were conducted to evaluate its performance on normal and salinity/sodicity‐degraded lands at two locations of different salinity/sodicity levels, S1 (UAF Farm, Normal Soil), S2 (Paroka Farm UAF, saline sodic), S3 (SSRI Farm, normal) and S4 (SSRI Farm, saline sodic) during 2013–2014. Two genotypes (Q‐2 and Q‐7) were grown in lines and were allowed to grow till maturity under RCBD split‐plot arrangement. Maximum seed yield (3,062 kg/ha) was achieved by Q‐7 at normal field (S1) soil which was statistically similar with yield of same genotype obtained from salt‐affected field S2 (2,870 kg/ha). Furthermore, low yield was seen from both genotypes from both S3 and S4 as compared to S1 and S2. Q‐7 was best under all four conditions. Minimum yield was recorded from Q‐2 (1,587 kg/ha) at S4. Q‐7 had higher SOD, proline, phenolic and K+ contents, and lower Na+ content in leaves as compared to Q‐2. High levels of antioxidants and K+/Na+ of Q‐7 helped to withstand salt stress and might be the cause of higher yields under both normal and salt‐affected soils. Seed quality (mineral and protein) did not decrease considerably under salt‐affected soils even improved seed K+, Mg2+ and Mn2+.  相似文献   

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