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1.
An experiment with factorial arrangement of treatments on a randomized complete block (RCB) design basis with three replications was conducted in a greenhouse during Spring 2010 to investigate changes in sodium ion (Na+), potassium ion (K+), Na+/K+ and to determine proline, protein content, and superoxide dismutase (SOD) of four wheat and four barley cultivars. Three salt levels {1, control (no salt), 7, and 13 dS m?1 [2.5 and 5 g salt [sodium chloride (NaCl) and sodium sulfate (Na2SO4) in 1:1 ratio] per kg of soil, respectively]} were used in this investigation. Salt stress treatments were applied 4 weeks after planting (at 2 leaf stage). Leaf samples were taken four weeks after imposition of salt treatment. The results showed that salinity caused an increased in proline and protein content, and SOD in all wheat and barley cultivars. The highest proline and protein content of barley and wheat cultivars at all salinity levels were observed in ‘Nimrooz’ and ‘Bam’ cultivars, respectively. At all salinity levels, wheat and barley cultivars ‘Kavir’ and ‘Nimrooz’, respectively, had the lowest Na+ content. Barley cultivar ‘Kavir’ and wheat cultivar ‘Bam’ had higher K+ and K+:Na+ ratios. This might be related to salt tolerance in these two cultivars. Wheat and barley cultivars showed differences with regard to proline, protein, and SOD content, Na+, K+, and K+:Na+ ratio, indicating existence of genetic diversity among the cultivars. These findings indicated that higher K+, K+:Na+ ratio, proline, protein, and SOD content could be the key factors, which offer advantage to barley over wheat for superior performance under saline conditions.  相似文献   

2.
An experiment was conducted to evaluate the effect of zinc (Zn) application on five rice cultivars grown under salt stress conditions. Two salinity levels of 0 and 10 dS m?1 were created with sodium chloride (NaCl) and foliar spray of Zn (0.05%; Chelated-Zn) was applied. A decrease in growth and yield related parameters were observed under salt stress, which was ameliorated in plants that received Zn foliar spray. Similar effects of salinity and Zn foliar spray were noted on photosynthetic rate, transpiration rate, stomatal conductance, water use efficiency, and water relations of plants. Salt induced increase in sodium (Na) content and decrease in other macro- and micronutrients contents were also reversed by Zn. Other salt tolerance indicating parameters likSe total free amino acids and total soluble sugars increased under Zn spray, clearing its role in improving salt tolerance.  相似文献   

3.
We studied the growth and ionic composition of five wheat genotypes (Inqlab-91, Uqab 2002, SARC-1, SARC-3, and SARC-5) grown under salinity stress to applied silicon. Plants were grown with three levels of salinity [0, 60, and 120 mM sodium chloride (NaCl)] in the presence of 0, 2, and 4 mM Si in nutrient solution for 40 days. Salinity stress significantly decreased shoot and root biomass in plants with varying degrees. Genotype SARC-3 exhibited higher salt tolerance than other genotypes. Silicon (Si) application significantly (P < 0.05) increased plant biomass at both control as well as under saline conditions. Genotypes differed significantly for their response to applied Si in terms of biomass production. Silicon application significantly (P < 0.01) increased potassium (K+) concentration in shoots. Enhanced salinity tolerance in wheat by Si application was attributed to increased K+ uptake thereby increasing K+/sodium (Na+) ratio and lower Na+ translocation towards shoot.  相似文献   

4.
A pot trial was conducted to clarify the effects of molybdenum (Mo) on photosynthesis and ionic homeostasis of Chinese cabbage under salinity stress. Mo was applied at three levels (0, 0.15, 0.3 mg kg?1). Ten days after sowing, 500 ml of 0.8% of NaCl solution was added to half of the plants for each treatment every 10th day for three consecutive times. The results revealed that fresh weight was significantly increased by application of Mo under salt stress; contents of chlorophyll a, chlorophyll b, carotene, and total chlorophyll were all raised by application of Mo; photosynthesis rate was enhanced by nonstomatal factors by application of Mo; and the ratios of potassium/sodium ions (K+/Na+), calcium/sodium ions (Ca2+/Na+), and magnesium/sodium ions (Mg2+/Na+) were all increased by application of Mo under salt stress. The study suggests that the application of Mo enhances salinity stress tolerance in Chinese cabbage by increasing the photosynthesis rate and the ionic homeostasis adjustment.  相似文献   

5.
Adequate regulation of mineral nutrients plays a fundamental role in sustaining crop productivity and quality under salt stress. We investigated the ameliorative role of potassium (K as K2SO4) in overcoming the detrimental effects of sodium chloride (NaCl) on sugarcane genotypes differing in salt tolerance. Four levels of NaCl (0, 100, 130 and 160 mM) were imposed in triplicate on plants grown in gravel by supplying 0 and 3 mM K. The results revealed that application of NaCl significantly (p ≤ 0.05) increased sodium (Na+) but decreased K+ concentrations in shoots and roots of both genotypes with a resultant decrease in K+/Na+ ratios. Physical growth parameters and juice quality were also markedly reduced with increasing NaCl concentrations compared with controls. However, addition of K alleviated the deleterious effects of NaCl and improved plant growth under salt stress. Cane yield and yield attributes of both genotypes were significantly (p ≤ 0.05) higher where K was added. Juice quality was also significantly (p ≤ 0.05) improved with the application of K at various NaCl levels. The results suggested that added K interfered with Na+, reduced its uptake and accumulation in plant tissues and consequently improved plant growth and juice quality in sugarcane.  相似文献   

6.
Application of plant growth regulator (PGR) may alleviate some negative effects of environmental stresses such as salinity. A controlled environment experiment was conducted to study barley (Hordeum vulgare L. cv. Reyhane) growth, yield, antioxidant enzymes and ions accumulation affected by PGRs under salinity stress conditions at Shiraz University during 2012. The treatments were PGRs at four levels—water (as control), cycocel (CCC, 19 mM), salicylic acid (SA, 1 mM), and jasmonic acid (JA, 0.5 mM)—and four salinity levels—no stress (0.67 dS m?1, as control), 5, 10, and 15 dS m?1, which were arranged in a factorial experiment based on completely randomized design with four replicates. The results showed that salinity stress significantly decreased plant height, peduncle length, leaf area, ear length, grain number, dry weight, grain yield, harvest index, potassium (K+) accumulation, and potassium/sodium (K+/Na+) concentration ratio, which were closely associated with stress severity. However, PGRs compensated some of these negative effects, so that SA foliar application had the most ameliorative effect. Salt stress also increased Na+ accumulation as well as the activity of peroxidase, catalase, and superoxide dismutase (SOD). Since ion discrimination and enhanced antioxidant enzymes are associated with salt tolerance, in this experiment PGRs application might have enhanced K+ accumulation and antioxidant enzyme activity. The activity of SOD and K+/Na+ ratio were found to be useful in salt tolerance manipulation in barley plants.  相似文献   

7.
Abstract

The effect of salinity on some physiological parameters in 16 barley genotypes with different salt tolerance was investigated. The results showed 50 mM NaCl treatment increased Na+/K+ ratio, malondialdehyde (MDA) and proline contents, and decreased cell membrane stability index (CMSI) and fresh shoot biomass (FSB) of all tested genotypes. Salt stress also resulted in a decreased chlorophyll (Chl) content and net photosynthesis (Pn) for most genotypes. Under higher salt stress (300 mM NaCl), the marked increase for Na+/K+, MDA, and proline content, and decrease for other parameters were found for all genotypes. The affected extent of these parameters by salt stress varied with genotypes. Proline accumulation in barley was associated with injured extent under salt stress, indicating it is not a defensive reaction to the stress. K+ uptake was less affected, whereas Na+ accumulation in plants was enhanced under high salt stress. The correlation analysis showed that MDA and proline content, Na+ concentration and Na+/K+ were negatively correlated with FSB, whereas other parameters examined in the study were positively correlated with FSB.  相似文献   

8.
Silicon (Si) is known to alleviate a number of abiotic stresses in higher plants including salinity stress. Two independent experiments were conducted to evaluate the role of Si in alleviating salinity stress in two contrasting wheat (Triticum aestivum L.) genotypes, Auqab-2000' (salt sensitive) and SARC-3 (salt tolerant). In the first experiment, genotypes were grown in hydroponics with two levels of salinity (0 and 60 mM NaCl) with and without 2 mM Si in a completely randomized design with four replications. Salinity stress significantly (P < 0.01) decreased all of the growth parameters, increased sodium (Na+) concentration, and decreased potassium (K+) concentration in shoots of both genotypes grown in hydroponics. Silicon significantly improved growth of both genotypes. The increase in growth was more prominent under salt stress (75%) than under normal condition (15%). In the second experiment, both genotypes were grown in normal [electrical conductivity (EC) = 1.23 d Sm–1] and natural saline field (EC = 11.92 d Sm–1) conditions with three levels of Si (0, 75, and 150 g g–1 Si) with three replications in a randomized complete block design. Silicon significantly (P < 0.05) decreased growth reduction in both genotypes caused by salinity stress. The grain yield under salt stress decreased from 62% to 33% and from 44% to 20% of the maximum potential in Auqab-2000 and SARC-3, respectively, when 150 g g–1 Si was used. Auqab-2000 performed better in normal field conditions, but SARC-3 produced more straw and grain yield in saline field conditions. Addition of Si significantly (P < 0.05) improved K uptake and reduced Na+ uptake in both of wheat genotypes and increased the K+/Na+ ratio in shoot. Enhanced salinity tolerance and improved growth in wheat by Si application was attributed to decreased Na+ uptake, its restricted translocation toward shoots, and enhanced K+ uptake.  相似文献   

9.
Soil management through the cultivation of salt-tolerant plants is a practical approach to combat soil salinization. In this study, salt tolerance of 35 barley (Hordeum vulgare L.) genotypes was tested at four salinity levels (0, 100, 200, and 300 mM NaCl in Hoagland nutrient solution) at two growth stages (germination and vegetative). The relationship between salinity tolerance and carbon isotope discrimination (CID) was also accessed. Results of the study carried out under laboratory conditions showed that a negative linear relationship was observed between salt concentration and germination as well as other growth parameters. Some genotypes showed good salt tolerance at germination but failed to survive at seedling stage. However, five genotypes, namely, Jau-83, Pk-30109, Pk-30118, 57/2D, and Akermanns Bavaria showed better tolerance to salinity (200 mM) both at germination and at vegetative growth stage. The salt tolerance of these barley genotypes was significantly correlated with minimum decrease in K+:Na+ ratio in plant tissue with increase in the root zone salinity. However, the case was reversed in sensitive genotypes. CID was decreased linearly with increase in root zone salinity. However, salt-tolerant genotypes maintained their turgor by osmotic adjustment and by minimum increase in diffusive resistance and showed minimum reduction in CID (Δ) with gradual increase in rooting medium salt concentration. Results suggested that the tolerant genotypes make osmotic adjustments by selective uptake of K+ and by maintaining a higher K+:Na+ ratio in leaves. Moreover, CID technique can also be good criteria for screening of salt-tolerant germplasm.  相似文献   

10.
Rice (Oryza sativa L.) is one of the most sensitive crops to drought, salt and cold stresses, particularly at post germination stage. The effects of these stresses on some physiological responses of two (a salt tolerant and a sensitive) rice cultivars ‘FL478’ and ‘IR29’ were investigated in this study. Two-day seedlings were transferred to MS media complemented with iso-osmotic concentrations of sodium chloride (NaCl; 0, 50, 100, and 150 mM) or mannitol (0, 100, 180, and 275 mM) at 25°C or four and 15°C for 10 days. Experiments were carried out based on completely randomized design, with at least three replicates. All three stresses decreased shoot growth, chlorophylls, carotenoids and root starch while increased shoot soluble sugars. The effect of exerted cold stress on growth, hydrogen peroxide (H2O2) and malonyldialdehyde levels, electrolyte leakage, chlorophylls and carotenoids contents was more than or comparable with drought, but greater than salinity. The results also indicated higher tolerance of ‘‘FL478’’ not only to salinity but also to drought compared to ‘‘IR29’’. Therefore, a mechanism for osmotic stress adjustment is probable in ‘‘FL478’’ in addition to low sodium (Na+) to potassium (K+) ratio in shoot tissues under salinity.  相似文献   

11.
The salinity tolerance of loquat grafted onto anger or onto loquat was studied. The plants were irrigated using solutions containing 5, 25, 35, 50, or 70 mM sodium chloride (NaCl) for five months. Different parameters of vegetative growth were studied, all of them showing that plants grafted onto loquat are much less salinity-tolerant than those grafted onto anger. Thus, the concentration of NaCl that produced a growth reduction of 50% (C50) for the growth parameters of the shoot was around 35 mM for loquat plants grafted onto loquat. With the NaCl levels employed, loquat-anger plants did not reach the C50. Lower chloride (Cl?) and sodium (Na+) uptake, higher potassium (K+)-Na+ selectivity and a lower reduction in the leaf magnesium (Mg2+) concentration for the loquat-anger combination can explain the higher salinity tolerance compared to loquat-loquat.  相似文献   

12.
Salinity is a major abiotic stress that limits the productivity of crops, particularly cereal crops, while decreasing nutrient availability, especially of nitrogen. An experiment was conducted to study the effects of salt stress [i.e., S0, S1, and S2 (control, 1.09; 5; and 10 dS m?1)] and four different nitrogen (N) levels [i.e., N0, N1, N2, and N3 (control, 175, 225, and 275 kg N ha?1)] on two maize hybrids, Pioneer 32B33 (salt tolerant) and Dekalb 979 (salt sensitive). The experiment was conducted in a wire house. The experiment was laid out with three factors in a completely randomized design. The plant tissue was analyzed for solute and ion contents. With the increase in salt stress and N rate, solute (i.e., glycinebetaine), protein, total soluble sugar, and total free amino acids accumulated in both hybrids. Nitrate (NO3) and nitrite (NO2) reductase activity decreased sharply at 10 dS m?1 compared to lower levels of salinity but it increased significantly with the addition of N. The uptake of potassium (K+), calcium (Ca2+), magnesium (Mg2+), N, and phosphorus (P) reduced significantly in shoots with increased salinity while the sodium (Na+) and chloride (Cl) contents were increased. It is concluded from the present study that at greater salinity level, hybrid Pioneer32B33 maintained statistically greater solute and ion contents excluding Na+ and Cl ions and significantly decreased enzyme activity. However, these parameters were increased by N rate.  相似文献   

13.
An experiment was conducted to determine if salinity stress alters the response and tolerance of soybean to defoliation. Four soybean [Glycine max(L.) Merr.] cultivars (‘Tachiutaka,’ ‘Tousan 69,’ ‘Dare’ and ‘Enrei’) in a growth chamber were exposed to two salinity treatments (0 and 40 mM NaCl) and two defoliation treatments (with and without defoliation). The interactive effects of salinity stress and defoliation on growth rate, leaf expansion, photosynthetic gas exchange, and sodium (Na+) accumulation were determined. The decrease in growth rate resulting from defoliation was more pronounced in plants grown under salinity stress than in those grown without the stress. Without salinity stress, defoliated plants of all four cultivars had leaf-expansion similar rates to those of the undefoliated ones, but the photosynthetic rates of their remaining leaves were higher than those of undefoliated plants. However, with salinity stress, defoliated ‘Tachiutaka’ and ‘Tousa 69’ had lower leaf expansion and photosynthetic rates than undefoliated plants. For cultivars ‘Dare’ and ‘Enrei,’ the defoliated plants had leaf-expansion rates similar to undefoliated ones, but the photosynthetic rate of the remaining leaves did not increase. Except for cultivar ‘Dare,’ defoliated plants grown under salinity stress had higher Na+ accumulation in leaves than undefoliated ones, and this result may be related to slow leaf expansion and photosynthesis. Salinity stress negatively affects soybean response and tolerance of defoliation, and the effects varied according to the salt tolerance of the cultivar.  相似文献   

14.
Maize (Zea mays L.) plants in the early stage of development were treated with 80 mM sodium chloride (NaCl) with or without supplemental calcium (Ca2+) (8.75 mM) for a seven day period. The effects of salinity on dry matter production and shoot and root concentrations of sodium (Na+), Ca2+, and potassium (K+) were measured for seven Pioneer maize cultivars. Salinity significantly reduced total dry weight, leaf area, and shoot and root dry weight below control levels. For all seven cultivars, Na+concentrations were reduced and leaf area was significantly increased by supplementing salinized nutrient solutions with 8.75 mM calcium chloride (CaCl2). The two cultivars with the lowest shoot and root Na+ concentrations under NaCl‐salinity showed the greatest increases in total, shoot and root dry weights with the addition of supplemental Ca. Shoot fresh weight/dry weight ratios for all cultivars were decreased significantly by both salinity treatments, but supplemental Ca2+ increased the ratio relative to salinity treatments without supplemental Ca. Root fresh weight/dry weight ratios were decreased only by salinity treatments with supplemental Ca. With NaCl‐salinity, cultivars which had lower shoot and root Na+ concentrations were found to be more salt sensitive and had significantly lower amounts of dry matter production than those cultivars which had higher shoot and root Na+ concentrations. It was concluded that Na+ exclusion from the shoot was not correlated with and was an unreliable indicator of salt tolerance for maize.  相似文献   

15.
To investigate the influence of potassium (K+) on the salinity tolerance of Chinese cabbage (Brassica pekinensis Rupr.) seedlings, the plants were cultured at three K+ levels (0, 5, or 10?mM), under normal (0?mM NaCl) and high-salt (100?mM NaCl) conditions. The results indicated that the dry weight of Chinese cabbage increased with the application of K+ under salt stress. Addition of K+ increased K+ concentrations and suppressed sodium (Na+) concentration, which eventually increased the K+/Na+ ratios in roots or shoots. Application of K+ enhanced the uptake of K+ and suppressed the uptake of Na+. Moreover, the ratios of shoot-K+/root-K+ increased considerably, but the ratios of shoot-Na+/root-Na+ decreased in response to K+ application. It was concluded that the application of K+ could enhance the salt stress tolerance in Chinese cabbage because more K+ than Na+ was absorbed and translocated from roots to shoots.  相似文献   

16.
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17.
Abstract

A greenhouse experiment was conducted on two salt‐tolerant, two moderately tolerant, and two sensitive Iranian and exotic bread wheat cultivars and their F1 generations to investigate the effect of salt stress on ion contents of young leaves, biomass yield, and salt stress tolerance index. The materials were evaluated in gravel culture under high salinity (EC=22.5 dSm?1) and nonstress (EC=2.0 dSm?1) conditions. Results of stress intensity showed that K+/Na+ ratio, biomass yield, and Na+ concentration were most affected by salt stress. There was no genetic relationship between Mg2+ and Ca2+ contents with salt tolerance. However, strong relationships were observed among K+/Na+ ratio, biomass yield, and stress tolerance index. Factor analysis revealed four factors, which explained 99.79% of the total variation among characters. Three‐dimensional plots based on the first three factor scores confirmed that the most salt‐tolerant cultivar was Roshan (an old Iranian cultivar), and Roshan×Alvand and Kharchia×Roshan and their reciprocal crosses were the best salt‐tolerant crosses.  相似文献   

18.
High concentrations of sodium (Na) are toxic to most plant species, making soil salinity a major abiotic stress in plant productivity world wide. It has been shown that, calcium (Ca2+) is an important determinant for plant salt tolerance and confers protective effects on plants under growing in sodic soils. Calcium plays an essential role in processes that preserve the structural and functional integrity of plant cell membranes, stabilizes cell wall structures, regulates ion transport and selectivity, and controls ion-exchange behavior as well as cell wall enzyme activities. The nature of these responses will vary depending on the plant genotype. One of the essential functions of Ca2+ is acting as a second messenger in stress signaling. Genetic evidence suggests that perception of salt stress leads to a cytosolic calcium-signal that activates the calcium sensor protein SOS3. SOS3 binds to and activates a ser/thr protein kinase SOS2. The activated SOS2 kinase regulates the activities of SOS1, a plasma membrane Na+/H+ antiporter, and NHX1, a tonoplast Na+/H+ antiporter. This results in either Na+ efflux out of cytosol or its compartmentation in vacuole.  相似文献   

19.
Although safflower is drought and salt tolerant, it is susceptible to drought and salinity at the germination and seedling stages. Priming techniques have been used to overcome salinity and drought tolerance at germination stage. Osmopriming potassium nitrate (KNO3) and hydropriming were used to determine drought [by polyethylene glycol (PEG)-6000 at water potentials of 0, ?0.3 and ?0.6 MPa] and salt electrical conductivity (EC) (values of the sodium chloride (NaCl) solutions were 0, 6 and 12 ds.m?1) tolerance of primed seeds of safflower. Germination index, shoot/root ration, germination uniformity, days to 50% germination (D50) and abnormal germination percentage were measured. Treatment 0f seeds with hydropriming increased germination index, shoot/root ration and germination uniformity, while decrease days to 50% germination under salt and water stress. Seed treated with KNO3 reduced abnormal germination percentage in salt stress. KNO3 improved germination uniformity and germination index of the low water potentials. As salinity increased, germination index and shoot/root ration were decreased, while germination uniformity, days to 50% germination and abnormal germination percentage were increased. Hydropriming enhanced germination under both salt and drought stresses and non-stress conditions. Therefore, hydropriming could be used to improved seed performance of safflower under saline and drought stress. This treatment dose not needs expensive chemicals or sophisticated equipment.  相似文献   

20.
盐胁迫下柚实生苗生长、矿质营养及离子吸收特性研究   总被引：7，自引：1，他引：7  
以坪山柚为材料,对盐胁迫下实生苗生长、矿质营养及离子吸收特性进行了研究。结果表明,沙培30d,80～200mmol/L盐胁迫,随盐浓度提高,坪山柚实生苗株高、叶面积、地上部干重和根部干重明显降低。溶液培养8d,坪山柚实生苗地上部及根Na+、Cl-含量随盐浓度的增加而增加,根及地上部K+、Ca2+、Mg2+以及P和Mn含量下降,Fe、Zn、Cu含量的变化因器官而异。其中,地上部Fe含量对盐胁迫敏感,可作为柚耐盐性鉴定指标。40mmol/L盐胁迫,坪山柚地上部K+/Na+、Ca2+/Na+、Mg2+/Na+值均显著下降,且Mg2+/Na+值+/Na+值>1;浓度≥160mmol/L盐胁迫,K+/Na+值+吸收、运转效率比Cl-高。  相似文献   

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