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1.
In order to study the effects of foliar applications of methanol (0, 15, and 30%) and NaCl salinity (0, 50, and 100?mM) on some physiological characteristics of Lavandula stoechas L. plants, a pot experiment was carried out at the Research Greenhouse of Azarbaijan Shahid Madani University. Physiological characteristics (stem and leaf dry weights, total phenolic and flavonoids compounds, chlorophyll a and K+ contents, and K+/Na+ ratio) were significantly affected by the interaction effects of Methanol foliar application and salinity levels. The highest K+ content, K+/Na+ ratio, chl a and stem dry weight, belonged to NaCl 0?×?Methanol 30% and NaCl 50?×?Methanol 30%. For the leaves’ dry weight, the greatest data were recorded for NaCl 0?×?Methanol 30% and NaCl 0?×?methanol 15%. Methanol spray promoted the total phenolic content, especially at NaCl 50?×?methanol 30% and NaCl 100?×?methanol 15% and 30% and flavonoid content at NaCl 50?×?methanol 30%. Anthocyanin content, essential oil percent, and flower dry weight were affected by NaCl salinity levels, and the highest amount of anthocyanin was recorded for the control treatment. The highest data for Essential oil was attained by the NaCl 0 and 50?mM. The Na+ content was affected by methanol foliar application and the highest amount was obtained in the control treatment. Both foliar application levels and salinity levels influenced the flower dry weight. The highest amount of the flower dry weight was recorded at 30% methanol spray level and 0?mM NaCl treatments. The results reveal that methanol application had significant effects on the physiological characteristics of Lavandula plants growing under salinity stress condition.  相似文献   

2.
Sodic‐alkalinity may be more deleterious to plant growth than salinity. The objectives of this study were to determine whether 5‐aminolevulinic acid (ALA: an essential precursor for chlorophyll biosynthesis) foliar application could improve the sodic‐alkaline resistance of Swiss chard (Beta vulgaris L. subsp. cicla ) by regulating water uptake, ionic homeostasis, photosynthetic capacity, and antioxidant metabolism. Eight‐week‐old uniform plants were grown in nutrient medium without and with a sodic‐alkaline regime generated by a mixture of NaHCO3 and Na2CO3 (NaHCO3 : Na2CO3 = 9:1 molar ratio) for 12 d, and leaves were sprayed daily with water or ALA. The Na+ and ALA concentrations were gradually increased to 60 mM and 120 μM, respectively. ALA foliar application alleviated the physiological damage from sodic‐alkalinity, as reflected by the increases in plant dry weight, relative growth rate, chlorophyll, Mg2+ concentration, and the decrease in Na+ concentration. However, ALA foliar application did not change the water uptake capacity or the concentration of K+, Fe3+, and endogenous ALA in leaf tissues under sodic‐alkaline conditions. ALA foliar application effectively mitigated damage from sodic‐alkalinity because of the increased activity of antioxidant enzymes (catalase and guaiacol peroxidase), particularly superoxide dismutase activity, which was maintained at the same level as for control plants. These results suggest that ALA foliar application alleviated sodic‐alkaline stress mainly owing to its antioxidant capacity, and superoxide dismutase has the main responsibility for reducing oxidative stress in Swiss chard.  相似文献   

3.
Plants grown in salt‐affected soils may suffer from limited available water, ion toxicity, and essential plant nutrient deficiency, leading to reduced growth. The present experiment was initiated to evaluate how salinity and soil zinc (Zn) fertilization would affects growth and chemical and biochemical composition of broad bean grown in a calcareous soil low in available Zn. The broad bean was subjected to five sodium chloride (NaCl) levels (0, 10, 20, 30, and 40 m mol kg?1 soil) and three Zn rates [0, 5, and 10 mg kg?1 as Zn sulfate (ZnSO4) or Zn ethylenediaminetetraaceticacid (EDTA)] under greenhouse conditions. The experiment was arranged in a factorial manner in a completely randomized design with three replications. Sodium chloride significantly decreased shoot dry weight, leaf area, and chlorophyll concentration, whereas Zn treatment strongly increased these plant growth parameters. The suppressing effect of soil salinity on the shoot dry weight and leaf area were alleviated by soil Zn fertilization, but the stimulating effect became less pronounced at higher NaCl levels. Moreover, rice seedlings treated with ZnSO4 produced more shoot dry weight and had greater leaf area and chlorophyll concentration than those treated with Zn EDTA. In the present study, plant chloride and sodium accumulations were significantly increased and those of potassium (K), calcium (Ca), and magnesium (Mg) strongly decreased as NaCl concentrations in the soil were increased. Moreover, changes in rice shoot Cl?, Na+, and K+ concentrations were primarily affected by the changes in NaCl rate and to a lesser degree were related to Zn levels. The concentrations of Cl? and Na+ associated with 50% shoot growth suppression were greater with Zn‐treated plants than untreated ones, suggesting that Zn fertilization might increase the plant tolerance to high Cl? and Na+ accumulations in rice shoot. Zinc application markedly increased Zn concentration of broad bean shoots, whereas plants grown on NaCl‐treated soil contained significantly less Zn than those grown on NaCl‐untreated soil. Our study showed a consistent increase in praline content and a significant decrease in reducing sugar concentration with increasing salinity and Zn rates. However, Zn‐treated broad bean contained less proline and reducing sugars than Zn‐untreated plants, and the depressing impact of applied Zn as Zn EDTA on reducing sugar concentration was greater than that of ZnSO4. In conclusion, it appears that when broad bean is to be grown in salt‐affected soils, it is highly advisable to supply plants with adequate available Zn.  相似文献   

4.
Salinity is one of the major environmental stressors which has deleterious effects on the growth, development, and yield of crops. Because of the gradual increase in soil and water salinity in the East Azarbaijan, Iran, Tanacetum balsamita L. cultivation in this region has always been associated with many problems. To study the effect of foliar spray of iron sulfate (FeSO4) (0, 750, and 1500 mg L?1) under sodium chloride (NaCl) salinity (0, 50, and 100 mM) on some physiological characteristics of Tanacetum balsamita L. plants, an experiment was conducted as a factorial based on complete randomized block design with three replications. Total soluble solids (TSS) and essential oil contents were significantly affected by the interaction effects of FeSO4 foliar application and salinity levels. The highest TSS and essential oil content were found in the plants under NaCl0 × FeSO4 1500 mg L?1 treatment combination. Leaf length, leaf fresh and dry weights were influenced by both Fe foliar application and salinity levels. Foliar application of iron (Fe) positively affected leaf length, leaves fresh and dry weights, root fresh and dry weights and peroxidase (POD) content, especially at 1500 mg L?1. Other traits such as leaf length, leaf fresh and dry weights, malondialdehyde (MDA), POD and catalase (CAT) contents were influenced by salinity levels. For POD, MDA, and CAT contents, the highest values were recorded with NaCl 50 and 100. The highest values of leaf length, leaf fresh and dry weights were found in the control plants.  相似文献   

5.
Soil or foliar application of nitrogen (N) can increase plant growth and salinity tolerance in cotton, but a combination of both methods is seldom studied under salinity stress. A pot experiment was conducted to study the effects of soil application (S), foliar application (F), and a combination of both (S+F) with labeled nitrogen (15N) on cotton growth, N uptake and translocation under salinity stress (ECe = 12.5 dS m?1). Plant biomass, leaf area, leaf chlorophyll (Chl) content, leaf net photosynthetic (Pn) rate, levels of 15N and [Na+] and K+/ Na+ ratio in plant tissues were determined at 3, 7, 14 and 28 days after N application (DAN). Results showed that soil or foliar nitrogen fertilization improved plant biomass, leaf area per plant and leaf photosynthesis, and a combination of soil- plus foliar-applied N was superior to either S or F alone under salinity stress. Although foliar application favored a rapid accumulation of leaf N and soil application a rapid accumulation of root N, S+F enhanced N accumulation in both leaf and root under salinity stress. The combined N application also maintained significantly greater [K+] and K+/Na+ than either soil or foliar application alone. Therefore, the improved plant growth and salinity tolerance under S+F relative to soil or foliar N application alone was attributed to the increased total uptake of N, balanced N concentrations in different tissues through enhanced uptake and accumulation in both leaves and roots, and higher ratio of K+/Na+.  相似文献   

6.
In this study, the effects of potassium doses (control, 150, 300 and 450?mg K2SO4 kg?1) and salt stress (control, 100?mM NaCl) on the yield and some element content of four medicinal and aromatic (Coriandrum sativum, Anethum graveolens, Ocimum basilicum and Foeniculum vulgare) plants were investigated in climate chamber. Both salinity and K fertiliser levels affected the fresh and dry weight of all evaluated plants. Anethum graveolens, Ocimum basilicum species are more sensitive to salinity, particularly at the vegetative productive stages. The highest fresh and dry weights of leaves, stems, roots and herb in Coriandrum sativum and Foeniculum vulgare species was observed in 300?mg?kg?1 fertiliser applications. In general, there was a relatively consistent and positive correlation between root element content and aerial parts element content. The result of the present study showed that NaCl treatment caused an increase in Na+ concentration, and a decrease in K+ and Ca+2 concentration in Coriandrum sativum, Anethum graveolens, Ocimum basilicum and Foeniculum vulgare. There was an interaction between K2SO4 application and salinity effects on Na+ concentration in the all evaluated plants. Given the experimental results, especially Foeniculum vulgare and Coriandrum sativum species were the most resistant to salt stress.  相似文献   

7.
Pistachio is one of the most important horticultural crops in Iran. The majority of the pistachio producing regions is located in arid and semi-arid areas with saline conditions. Therefore, selection of suitable rootstocks is important for increasing yield efficiency of this important nut crop. In this study, the effect of four water salinity levels (0.75, 5, 10 and 15 ds m?1) on growth indices and physiological parameters of four Pistacia vera L. rootstocks (Badami-e-Zarand A, Badami-e-Zarand B, Qazvini, and Sarakhs) were investigated under greenhouse conditions. After treatment for three months, leaf dry weight was reduced by about 30-50% at an irrigation water electrical conductivity (ECw) of 10 ds m?1. Badami-e-Zarand B was the most vigorous rootstock at the highest EC. Decreases in root and stem dry weight (average of all rootstocks combined) occurred at water salinity of 10 ds m?1. Chemical analysis of shoot and root indicated that the salinity affected the concentration and distribution of sodium (Na+), potassium (K+), and calcium (Ca2+) in pistachio rootstocks. The concentrations of Na+ and K+ increased with a rise in water salinity levels. Comparison between Na+ concentration of shoot and root showed that all examined rootstocks limited the Na+ transportation to shoot tissue up-to 15 ds m-1, and retained it in the roots. However, this ability was less in the Sarakhs rootstock. Based on measured parameters, Badami-e-Zarand B and Sarakhs could be considered as tolerant and sensitive pistachio rootstocks to water salinity, respectively.  相似文献   

8.
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   

9.
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   

10.
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   

11.
Abstract

A salt-sensitive cucumber cultivar “Jinchun No. 2” (Cucumis sativus L.) was used to investigate the role of proline in alleviating salt stress in cucumber. Proline was applied twice (day 0 and day 4 after salt treatment) as a foliar spray, with a volume of 25?mL per plant at each time. Plant dry weight, leaf relative water content, proline, malondialdehyde (MDA), Na+, K+ and Cl? contents, as well as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) activities in the plants were determined at day 8 after salt treatment. The results showed that 100?mmol?L–1 NaCl stress significantly decreased plant dry weight, leaf relative water and K+ contents, and increased leaf MDA, Na+ and Cl? contents and SOD, POD, CAT and APX activities. However, leaf proline accumulation was not affected by salinity. The exogenous application of proline significantly alleviated the growth inhibition of plants induced by NaCl, and was accompanied by higher leaf relative water content and POD activity, higher proline and Cl? contents, and lower MDA content and SOD activity. However, there was no significant difference in Na+ and K+ contents or in CAT and APX activities between proline-treated and untreated plants under salt stress. Taken together, these results suggested that the foliar application of proline was an effective way to improve the salt tolerance of cucumber. The enhanced salt tolerance could be partially attributed to the improved water status and peroxidase enzyme activity in the leaf.  相似文献   

12.
In order to study effects of sodium bicarbonate (NaHCO3) stress in irrigation water on photosynthetic characteristics and iron (Fe) and sodium (Na+) translocation content of pomegranate plants, a factorial experiment was conducted based on completely randomized design with three cultivars of pomegranate (“Gorch-e-Dadashi,” “Zagh-e-Yazdi,” and “Ghermez-e-Aliaghai”) and four concentrations of NaHCO3 (0, 5, 10, and 15 mM), with three replications. The results of plant analysis indicated that NaHCO3 affected chlorophyll index, Fv/Fm, and performance index (PI) in upper and lower leaves of shoots and also the translocation of Na+ and Fe. The results also showed that Fe translocation from root to shoot reduced at 15 mM level of NaHCO3. The highest Na translocation and the lowest Fe translocation were observed in Zagh-e-Yazdi and Ghermez-e-Aliaghai cultivars, respectively. The ratio of sodium/potassium (Na+/K+) in stems was higher than that in roots and leaves, and the observed chlorophyll content of upper leaves was also lower than that of lower leaves. Based on the measured parameters Gorch-e-Dadashi cultivar showed less relative sensitivity than other cultivars to NaHCO3 of irrigation water through maintaining the lower Na+ transport to the shoots, and improvement of Fe transport to shoots.  相似文献   

13.
Two cultivars of wheat (Triticum aestivum L.) with differential salinity tolerance were compared by evaluating the growth attributes, pigment composition and accumulation of Na+, K+, Zn2+, Fe 2+, Mn 2+ and proline. Wheat cultivars Al-Moiaya (AM) (salt tolerant) and Habbe-Druma (HD) (salt sensitive) were subjected to four levels of salinity (1.21 dS m?1, 4.4 dS m?1, 8.8 dS m?1 and 13.2 dS m?1) in factorial combinations with three drought stress (FC 30%, FC 60% and FC 90%) treatments in a randomized complete block design. Plant dry weight, leaf area ratio (LAR), soluble protein and total chlorophyll (Chl) content were higher in AM than HD. Salt-tolerant AM maintains a higher K+/ Na+ ratio and thereby is able to grow better than the salt-sensitive HD under both the stresses. The lower foliar Na+ in AM resulted in retention of higher Chl content, reflected in the strong positive correlations between plant ion status and Chl contents (Na+-Chl r2 = 0.83; Chl- Fe2+ r2 = 0.76; Zn2+ r2 = 0.93 and Mn2+ r2 = 0.88). In conclusion, our results suggested that the K+/Na+ ratio, exclusion of Na+ and ion homeostasis play much more important roles in the tolerance to salinity and drought stress than the compatible osmolyte, proline.  相似文献   

14.
The effect of sodium chloride (NaCl), sodium sulfate (Na2SO4), and potassium chloride (KCl) on growth and ion concentrations of faba bean (Vicia faba L. cv. Troy) was studied. After 14 or 15 d of isoosmotic treatment with 100 mM NaCl or 75 mM Na2SO4, respectively, plants developed toxicity symptoms. These symptoms were characterized by local and nonchlorotic wilting spots, which later turned to black, necrotic spots. In contrast to NaCl or Na2SO4 treatment, plants treated with 100 mM KCl did not show these symptoms. The symptoms occurred on those leaves that accumulated highest concentrations of Na+ and showed highest Na+ : K+ ratios. Our results indicate that Na+ toxicity inducing K+ deficiency is responsible for the spot necrosis of faba bean. Additionally, chlorotic symptoms occurred. The concentrations of Na+ and Cl– were determined in chlorotic leaves and in isolated chloroplasts. The reduction of chlorophyll in leaves after NaCl exposure may be explained in terms of high Cl– concentrations in the chloroplasts and appears to depend on high Na+ concentrations. Chlorotic toxicity symptoms can be avoided by additional Mg2+ application.  相似文献   

15.
ABSTRACT

Effects of three supplemental calcium (Ca++; 2.5, 5.0, and 10 mole m?3) concentrations on ion accumulation, transport, selectivity, and plant growth of salt-sensitive species, Brassica rapa ‘Sani’ in saline medium were investigated. Supplemental Ca++ in the presence of 125 mol m?3 sodium chloride (NaCl) did not improve the dry weight and leaf area indicating no role played by Ca++ in the alleviation of salinity induced growth inhibition. However, calcium chloride (CaCl2) did significantly affect sodium (Na+), potassium (K+), and Ca++ contents of roots and shoots. The ion contents of shoots were significantly greater than those of roots per g dry weight, indicating ion transportation to shoots is greater than ion accumulation in roots. Use of CaCl2 in 125 mol m?3 NaCl reduced the Na+ content but increased K+ and Ca++ contents in shoots. Sodium contents in shoots differed among the supplemental Ca++ treatments indicating the role of CaCl2 in Na+ ions transportation. Calcium content in shoots declined significantly in the control treatment (0 CaCl2) but increased significantly in 10 mol m?3 CaCl2. The root also showed the effects of Ca++ on the reduction of Na+ content and the increase of K+ and Ca++ content. Unexpectedly, 5 mol m?3 CaCl2 induced the highest Na+ content in roots at 16 days after treatment. Supplemental CaCl2 application influenced the K+ or Ca++ selectivity over Na+ in two ways, ion accumulation at roots and transport to shoots. However, high CaCl2 treatments allowed greater Ca++ selectivity over Na+ than low CaCl2. Likewise, high supplemental CaCl2 showed higher K+ selectivity over Na+ than low CaCl2. A marked increase in K+ versus Na+ selectivity for the transport process occurred at 10 mol m?3 CaCl2 treatments. The roots and shoots exhibited higher K+/Na+ and Ca++/Na+ ratios in high CaCl2 treatment than in low. The results are discussed in context to supplemental Ca++ concentrations, ions accumulation, transportation and selectivity of salt sensitive Brassica rapa cultivar.  相似文献   

16.
《Journal of plant nutrition》2013,36(12):2689-2704
ABSTRACT

Salinity is among the most widespread and prevalent problems in irrigated agriculture. Many members of the family Chenopodiaceae are classified as salt tolerant. One member of this family, which is of increasing interest, is quinoa (Chenopodium quinoa Willd.) which is able to grow on poorer soils. Salinity sensitivity studies of quinoa were conducted in the greenhouse on the cultivar, “Andean Hybrid” to determine if quinoa had useful mechanisms for salt tolerant studies. For salt treatment we used a salinity composition that would occur in a typical soil in the San Joaquin Valley of California using drainage waters for irrigation. Salinity treatments (ECi ) ranging from 3, 7, 11, to 19?dS?m?1 were achieved by adding MgSO4, Na2SO4, NaCl, and CaCl2 to the base nutrient solution. These salts were added incrementally over a four-day period to avoid osmotic shock to the seedlings. The base nutrient solution without added salt served as the non-saline control solution (3?dS?m?1). Solution pH was uncontrolled and ranged from 7.7 to 8.0. For comparative purposes, we also examined Yecora Rojo, a semi-dwarf wheat, Triticum aestivum L. With respect to salinity effects on growth in quinoa, we found no significant reduction in plant height or fresh weight until the electrical conductivity exceeded 11?dS?m?1. The growth was characteristic of a halophyte with a significant increase in leaf area at 11?dS?m?1 as compared with 3?dS?m?1 controls. As to wheat, plant fresh and dry weight, canopy height, and leaf area did not differ between controls (3?dS?m?1) and plants grown at 7?dS?m?1. Beyond this threshold, however, plant growth declined. While both quinoa and wheat exhibited increasing Na+ accumulation with increasing salinity levels, the percentage increase was greater in wheat. Examination of ion ratios indicated that K+:Na+ ratio decreased with increasing salinity in both species. The decrease was more dramatic in wheat. A similar observation was also made with respect to the Ca2+:Na+ ratios. However, a difference between the two species was found with respect to changes in the level of K+ in the plant. In quinoa, leaf K+ levels measured at 19?dS?m?1 had decreased by only 7% compared with controls. Stem K+ levels were not significantly affected. In wheat, shoot K+ levels had decreased by almost 40% at 19?dS?m?1. Correlated with these findings, we measured no change in the K+:Na+ selectivity with increasing salinity in quinoa leaves and only a small increase in stems. In wheat however, K+:Na+ selectivity at 3?dS?m?1 was much higher than in quinoa and decreased significantly across the four salinity levels tested. A similar situation was also noted with Ca2+:Na+ selectivity. We concluded that the greater salt tolerance found in quinoa relative to wheat may be due to a variety of mechanisms.  相似文献   

17.
Infection with Neotyphodium spp. endophytes increases resistance to drought stress and soil mineral imbalances in tall fescue (Festuca arundinacea Schreb. = Lolium arundinaceum (Schreb.) S. J. Darbysh.) and meadow fescue (Festuca pratensis Huds. = Lolium pratense (Huds.) Darbysh.). We hypothesized that resistance of these grasses to salinity stress may also be attributed to endophyte infection. Two tall fescue genotypes, Fa75 and Fa83, and one meadow fescue genotype, Fp60, infected (E+) with their endophytic fungi, Neotyphodium coenophialum (Glenn, Bacon and Hanlin) and N. uncinatum (Glenn, Bacon and Hanlin), respectively, and their noninfected counterparts (E–) were cultured in nutrient solution at three salinity levels of 0, 85, and 170 mM NaCl. Except for genotype Fa75, E+ plants exhibited higher leaf survival rates than E– clones at a high salinity level (170 mM). Root dry matter was higher in E+ than in E– plants, but shoot dry matter was not affected by endophyte infection. This resulted in a lower shoot‐to‐root ratio in E+ plants (1.63) compared with E– plants (2.40). Sodium (Na+) and chloride (Cl–) concentrations were greater in roots of E– than in E+ clones. In shoots, Na+ and Cl– concentrations were not affected by the endophyte. In contrast, E+ plants accumulated more potassium (K+), which resulted in a greater K+ : Na+ ratio in shoots of E+ than in those of E– plants. Our results show that endophyte infection reduced Na+ and Cl– concentrations in tall fescue and meadow fescue roots but increased K+ concentrations in the shoots. Based on these results, we conclude that endophyte‐infected grasses may thrive better in salinity‐stress environments.  相似文献   

18.
Calcium (Ca2+) amelioration of the plant's growth response to salinity depends on genetic factors. In this work, supplemental Ca2+ did not improve growth in Phaseolus vulgaris L. cv. Contender under high‐saline conditions and negatively affected several physiological parameters in nonsalinized plants. The response to supplemental Ca2+ was examined using plants grown in 25% modified Hoagland solution at different Na+ : Ca2+ ratios. In control plants (1 mM Ca2+; 1 mM Na+) surplus Ca2+ (4 or 10 mM) was associated with stomatal closure, decrease of hydraulic conductivity, sap flow, leaf specific dry weight, leaf K+ and leaf Mg2+ concentrations, and inhibition of CO2 assimilation. Leaf water content was enhanced, while water‐use efficiency and dry matter were unaffected during the 15 d experimental period. The Ca2+ effect was not cation‐specific since similar results were found in plants supplied with high external Mg2+ or with a combination of Ca2+ and Mg2+. Relative to control plants, salinization (50 and 100 mM NaCl) caused a decrease in dry matter, hydraulic conductivity, sap flow, leaf Mg2+ activity, and inhibition of stomatal opening and CO2 assimilation. However, NaCl (50 and 100 mM NaCl) enhanced leaf K+ concentration and water‐use efficiency. At 100 mM NaCl, leaf water content also significantly increased. Supplemental Ca2+ had no amelioration effect on the salt‐stress response of this bean cultivar. In contrast, the 50 mM–NaCl treatment improved stomatal conductance and CO2‐assimilation rate in plants exposed to the highest Ca2+ concentration (10 mM). Phaseolus vulgaris is classified as a very NaCl‐sensitive species. The similarities in the effects caused by supplemental Ca2+, supplemental Mg2+, and NaCl salinity suggest that P. vulgaris cv. Contender has a high non‐ion‐specific salt sensitivity. On the other hand, the improvement in gas‐exchange parameters in Ca2+‐supplemented plants by high NaCl could be the result of specific Na+‐triggered responses, such as an increase in the concentration of K+ in the leaves.  相似文献   

19.
In order to assess the effectiveness of foliar‐applied potassium (K+, 1.25%) using different salts (KCl, KOH, K2CO3, KNO3, KH2PO4, and K2SO4) in ameliorating the inhibitory effect of salt stress on sunflower plants, a greenhouse experiment was conducted. Sodium chloride (150 mM) was applied through the rooting medium to 18 d–old plants and after 1 week of salt treatment; different K+‐containing salts were applied twice in 1‐week interval as a foliar spray. Salt stress adversely affected the growth, yield components, gas exchange, and water relations, and also caused nutrient imbalance in sunflower plants. However, foliar‐applied different sources of potassium improved shoot and root fresh and shoot dry weights, achene yield, 100‐achene weight, photosynthetic rate, transpiration rate, stomatal conductance, water‐use efficiency, relative water content, and leaf and root K+ concentrations of sunflower plants grown under saline conditions. Under nonsaline conditions, improvement in shoot fresh weight, achene yield, 100‐achene weight, photosynthetic and transpiration rates, and root Na+ concentration was observed due to foliar‐applied different K sources. Of the different salts, K2SO4, KH2PO4, KNO3, and K2CO3 were more effective than KCl and KOH in improving growth and some key physiological processes of sunflower plants.  相似文献   

20.
The different responses of two populations of Suaeda salsa (Linn.) Pall. (saline seepweed) from an intertidal zone and a saline inland zone to salinity [1 or 500 mM sodium chloride (NaCl)] and nitrogen [N; 0.05, 1, or 10 mM nitrate (NO3 ?)‐N] were investigated. Greater NO3 ?‐N supply (10 mM) increased shoot dry weight for the two populations of S. salsa, especially for S. salsa from the saline inland zone. Greater NO3 ?‐N supply (10 mM) increased the concentrations of chlorophyll and carotenoid in leaves and the NO3 ? and potassium (K+) concentrations in shoots for both populations. Greater NO3 ?‐N supply (10 mM) increased shoot Na+ in S. salsa from the intertidal zone. In conclusion, S. salsa from the saline inland zone is more responsive to NO3 ?‐N supply than the intertidal population. Greater NO3 ?‐N supply can help the species, especially the intertidal population, to grow and to mediate ion homeostasis under high salinity.  相似文献   

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