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1.
The effects of NaCl salt (EC = 16 dS m−1) on water potential, and accumulation of proline, Na+ and K+ in leaves on the main stem of 30 wheat cultivars (Triticum aestivum L.) at awn appearance and 20 days after anthesis (20 DAA) were evaluated in a greenhouse experiment. Plants were arranged in a according to a randomized complete block design with factorial treatments in three replications. Proline accumulation at 20 DAA increased with increasing salt stress. This increase was 27.4-fold with the salt-sensitive cultivar “Ghods,” while the mean was 5.2-fold for 19 salt-resistant cultivars. Positive correlations between proline, and K+ + Na+ concentrations associated with higher sensitivity to salt stress indicated that proline may not have a protecting role against salt stress. No correlation was observed between leaf proline and water potential. Almost no contribution to the osmotic adjustment seems to be made by proline. The contribution made by proline to the osmotic adjustment of plants at 20 DAA was 0.69 bar, whereas that made by K+ and Na+ was 2.11 and 4.48 bar, respectively. The 30 wheat CVs used in this experiment showed different performances regarding the traits observed. Eleven of them showing the higher stress sensitivity indices had the highest level of proline and Na+ concentrations. They were considered to be salt-sensitive cultivars. Among the others, nine cultivars showed salt tolerance with almost the same Na+ and proline concentrations, but a higher K+/Na+ selectivity of ions from leaf to grains. In 10 of the cultivars, Na+ and proline concentrations were low, indicating the presence of a salt avoiding mechanism.  相似文献   

2.
【目的】土壤盐碱化是制约农作物产量的主要因素之一,盐胁迫影响养分运输和分布,造成植物营养失衡,导致作物发育迟缓,植株矮小,严重威胁着我国的粮食生产。在必需营养元素中,氮素是需求量最大的元素,NO-3和NH+4是植物吸收氮素的两种离子形态。植物对盐胁迫的响应受到不同形态氮素的调控,研究不同形态氮素营养下植物的耐盐机制对提高植物耐盐性及产量具有重要的意义。【方法】本文以喜硝植物油菜(Brassica napus L.)和喜铵植物水稻(Oryza sativa L.)为试验材料,采用室内营养液培养方法,研究了NO-3和NH+4对Na Cl胁迫下油菜及水稻苗期生长状况、对Na+运输和积累的影响,以对照与盐胁迫植株生物量之差与Na+积累量之差的比值,评估Na+对植株的伤害程度。【结果】1)在非盐胁迫条件下,硝态氮营养显著促进油菜和水稻根系的生长;盐胁迫条件下,油菜和水稻生物量均显著受到抑制,Na Cl对供应铵态氮营养植株的抑制更为显著。2)盐胁迫条件下,两种供氮形态下,油菜和水稻植株Na+含量均显著增加,硝态氮营养油菜叶柄Na+显著高于铵态氮营养,叶柄Na+含量/叶片Na+含量大于铵营养油菜,硝态氮营养水稻根系Na+含量显著低于铵营养,地上部则相反。3)铵营养油菜和水稻Na+伤害度显著高于硝营养植株。4)盐胁迫条件下,硝态氮营养油菜地上部和水稻根系K+含量均显著高于铵态氮营养。5)盐胁迫条件下,硝营养油菜和水稻木质部Na+浓度,韧皮部Na+和K+浓度及水稻木质部K+浓度均高于铵营养植株。【结论】与铵营养相比,硝营养油菜和水稻具有更好的耐盐性。硝态氮处理油菜叶柄Na+显著高于铵态氮处理,能够截留Na+向叶片运输。同时,供应硝态氮营养更有利于油菜和水稻吸收K+,有助于维持植物体内离子平衡。盐胁迫下,硝营养油菜和水稻木质部Na+浓度,韧皮部Na+和K+浓度及水稻木质部K+浓度均高于铵营养植株,表明硝态氮营养油菜和水稻木质部-韧皮部对离子有较好的调控能力,是其耐盐性高于铵营养的原因之一。  相似文献   

3.
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   

4.
Salt and alkali stress limit crop growth and reduce agricultural productivity worldwide, which have led to increased interest in enhancing salt tolerance in crop plants. Sweet sorghum (Sorghum bicolor (Linn.) Moench) is a monocotyledonous crop species that shows greater tolerance to salt–alkali stress than most other crops, although the underlying mechanisms behind this tolerance remain unclear. Therefore, we investigated the effects of salt and alkali stresses on two sweet sorghum varieties M-81E, which is stress tolerant, and 314B, which is stress sensitive. Namely, we surveyed plant growth parameters, measured Na+ and K+ distributions at the level of the whole plant as well as in three specific tissues, and then determined the activities of H+-ATPase, H+-PPase and Na+/H+ exchange in root vacuole membranes under stress conditions. Following treatment of the seedlings for 3 days with salt or alkali solutions, the plant growth was inhibited and Na+ levels in the whole plant, leaves, sheath, and roots were increased in both genotypes. Under alkali stress, K+ levels in the whole plant, leaves, sheath, and roots were decreased in both genotypes. M-81E roots accumulated significantly higher levels of Na+ than leaves, whereas the opposite was true for 314B. Under salt stress, both the hydrolytic and proton-transporting activities of V-H+-ATPase were enhanced and Na+/H+ exchange activity was dramatically upregulated, whereas V-H+-PPase activity was decreased. M-81E showed a greater capacity to compartmentalize Na+ within root cell vacuoles and maintain higher levels of K+ uptake compared with 314B, resulting in higher K+/Na+ transport selectivity in this genotype. These results also demonstrated that H+-ATPase activity and ionic homeostasis (Na+/K+) were likely important contributors to the tolerance of saline-alkali stress and crucially important for understanding alkaline stress in both crops and wild plants.  相似文献   

5.
基于离子稳态的野生与栽培番茄及其杂交F1的耐盐性差异   总被引：1，自引：0，他引：1  
以野生番茄-醋栗番茄D4-101(Solanum pimpinellifolium)(WT)、自交系番茄栽培种7818D(S.esculentum)(CT)及二者杂交产生的F1代品系为材料,探讨50、100及200 mmol L-1Na Cl胁迫处理对番茄生物量和离子吸收分配的影响。结果表明:盐胁迫下,植株干重的降幅由大到小依次是:CTWTF1。随着盐胁迫程度加大,三个品种(系)Na+含量均增高,而K+含量显著降低。盐胁迫处理下三个品种(系)的K+/Na+比均显著降低,而品种间降幅差异不大。盐胁迫强度的增加显著提高三个品种(系)根的K+、Na+的选择性比率(SK,Na),其增幅由大到小依次是:WTF1CT。在茎部,盐胁迫则显著降低了三个品种(系)的SK,Na,但是盐处理之间WT茎的变化甚小,而随着盐分强度的上升,CT茎SK,Na的降幅显著高于F1的。盐胁迫下三个品种(系)叶片的SK,Na均增加,但是随着盐度的增加,WT叶的SK,Na逐渐下降,而CT和F1的SK,Na逐渐上升,且F1的SK,Na上升显著高于CT的。综上所述,F1植株在维持离子稳态方面接近于野生亲本,尤其是叶片,导致F1不仅长势好,而且还具有较亲本更好的耐盐性。  相似文献   

6.
A study of the salinity effect on mineral content in rice genotypes differing in salt tolerance was conducted in a factorial Completely Randomized Design experiment. The results indicated that the genotypes developed differently by mutation conventional breeding. NS15 represented as salt-sensitive, Pokkali was included as an internationally salt-tolerant check and Iratom24 was moderately tolerant. The content of Na+, Ca2+, Mg2+ and Cl? followed an increasing pattern in roots and shoots of all the rice genotypes due to increasing salinity levels except Ca2+ and Mg2+ in the root. However, the concentration of K+ showed more or less an increasing pattern in root and a decreasing pattern in shoot. The concentration of Na+ and Ca2+ sharply increased with increasing the salinity levels in both the roots and shoots of NS15. The concentration of K+ sharply decreased in shoot and increased in the root of susceptible genotype NS15 with increasing salinity over 6 dS m?1 salinity levels, where the transformation of K+ from root to shoot was disrupted by Na+. The Cl? content sharply increased with increasing salinity in the root of NS15 as compared to shoot. The effect of different salinity levels on Na+/K+ ratio in the shoots of the selected rice genotypes sharply increased in susceptible genotype NS15 as compared to the other genotypes.  相似文献   

7.
烟草是重要的模式植物和经济作物,盐害和干旱两种环境因子对其生长发育、产量和品质都危害很大。为了提高烟草的耐盐抗旱性,本研究利用农杆菌介导的遗传转化法在烟草中过量表达了碱蓬液泡膜Na~+/H~+逆向转运基因SsNHX1,对转基因烟草的耐盐及抗旱性进行表型鉴定和各项生化指标的检测,以期得到耐盐抗旱表性良好的SsNHX1转基因烟草。表型分析发现,SsNHX1基因过表达株系L1和L5的抗盐能力比野生型显著提高,表现为盐胁迫条件下仍能保持旺盛的生长且根系的伸长未受抑制。SsNHX1过表达株系在叶片和根系中积累了更多的Na~+和K~+,同时Na~+含量增长速率较快,而K~+含量降低速率较缓,并可维持较高的叶片相对含水量和叶绿素含量,及较低的丙二醛含量和相对电导率。干旱胁迫发现,过表达株系受干旱胁迫程度更小,并在复水后迅速恢复正常生长。同时,过表达株系的丙二醛含量和相对电导率显著低于野生型,且维持了较高的叶片相对含水量及叶绿素含量。这些结果说明SsNHX1基因在烟草中过量表达后,降低了盐胁迫和干旱胁迫对烟草根系及细胞膜的损伤,并通过调节离子含量、降低细胞的渗透势,维持了叶片较高的相对含水量和叶绿素含量,最终提高了烟草的抗盐和抗旱性。  相似文献   

8.
Drip irrigation offers potential for rice (Oryza sativa L.) production in regions where water resources are limited. However, farmers in China’s Xinjiang Province report that drip-irrigated rice seedlings sometimes suffer salt damage. The objective of this study was to learn more about the effects of soil salinity and soil temperature on the growth of drip-irrigated rice seedlings. The study consisted of a two-factor design with two soil salinity treatments (0 and 1.8 g kg?1 NaCl) and three soil temperature treatments (18°C, 28°C and 36°C). The results showed that shoot biomass, root biomass and root vigor were greatest when seedlings were grown with no salt stress (0 g kg?1 NaCl) at 28°C. Moderate salt stress (1.8 g kg?1 NaCl) combined with high temperature (36°C) significantly reduced root and shoot biomass by 39–53%. Moderate salt stress and high temperature also increased root proline concentration by 77%, root malonyldialdehyde concentration by 60% and seedling mortality by 60%. Shoot and root Na+ concentrations, shoot and root Na+ uptake and the Na+ distribution ratio in shoots were all the greatest when moderate salt stress was combined with high temperature. In conclusion, high soil temperature aggravates salt damage to drip-irrigated rice seedlings. Therefore, soil salinity should be considered before adopting drip-irrigation for rice production.  相似文献   

9.
Fern leaf lavender (Lavandula multifida L.) is a perennial shrub native to Almería with known medicinal properties, which grows in saline soils that are increasingly present in the Mediterranean region. However, the effects of salinity on the mineral nutrition and physiology of L. multifida are unknown. In the present study, we evaluated the salt resistance of this species and compared it with other members of the Lamiaceae . Plants of L. multifida were grown in pots in a mixture of sphagnum peat‐moss and Perlite, and treated with five different NaCl concentrations [10 (control), 30, 60, 100, and 200 mM NaCl] over a period of 60 d. The effects of different levels of salinity on mineral nutrient and osmolyte concentrations and on biomass were evaluated. Our results show that L. multifida plants were able to grow with 60 mM NaCl without significant biomass reduction. Na+ and Cl− were the main contributors to the osmotic potential in both roots and leaves, whereas total soluble sugars (TSS) and proline made only a small contribution. The concentrations of TSS and proline showed different trends in the different organs: in roots, both showed the highest concentrations at 60 mM NaCl, whereas in leaves TSS increased and proline decreased with increasing salt stress. To survive salinity, L. multifida plants increased salt excretion (Na+ and Cl−) by leaves at 100 and 200 mM NaCl and leaf succulence at 60, 100, and 200 mM NaCl. Excessive accumulation of Na+ and Cl− was avoided by shedding leaves. Our results indicate that L. multifida is better adapted to salinity compared to other members of the Lamiaceae ¸ a consideration that is particularly relevant for their growth in arid saline areas.  相似文献   

10.
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   

11.
Tolerance of gerbera (Gerbera jamesonii L.) to long-term sodium chloride (NaCl) salt stress was evaluated by subjecting plants to 0, 10, 20, 30 and 40 mM NaCl levels for ten weeks. Increased NaCl led to a significant decrease in leaf and stem biomass. Salt stress significantly affected sodium (Na+), potassium (K+) concentrations in leaves, stems and roots leading to sharp declines in K+/Na+ ratios. Magnesium concentrations in stems and roots also showed significant declines. Adverse effect of salt stress on chlorophyll content was also significant. Proline seemed less effective in osmotic adjustment under long-term high salt stress. Switching from vegetative to reproductive growth phase was crucial for certain physiological functions. Leaf Na+ concentration showed significant correlation with important traits. These data suggest that NaCl threshold level in irrigation water for gerbera is around 10 mM. Leaf fresh weight, chlorophyll content and leaf K+/Na+ ratio are promising indicators of salt-sensitivity of gerbera.  相似文献   

12.
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   

13.
转大麦烟酰胺合成酶基因提高水稻逆境胁迫耐受性的研究   总被引：1，自引：0，他引：1  
维持铁等金属离子的动态平衡是保持植物细胞功能正常的先决条件。烟酰胺合成酶基因在单子叶禾本科的缺铁胁迫应答反应中起着关键作用,它的催化产物烟酰胺(NA)是铁及其他二价金属离子在体内吸收和转运的重要载体,且能与Fe2+结合形成Fe2+-NA复合物,从而使植物在酸性土壤中免受铁毒害。利用农杆菌介导法,将大麦烟酰胺合成酶基因NASHOR1转入水稻台北309中,经PCR及PCR-Southern杂交检测,确定目的基因已经整合到水稻基因组中。铁、锰、铜和锌含量的检测结果显示:与非转基因对照植株相比,转基因植株的金属元素含量都明显提高,铜、锌、锰和铁元素含量分别增加了15%、80%、31%和44%,但铁、锰和锌元素增量在株系间差异较大。在干旱胁迫下,转基因植株的超氧化物歧化酶(SOD)活性和脯氨酸含量都高于非转基因对照植株的,暗示大麦烟酰胺合酶基因在一定程度上提高了水稻的耐旱性。  相似文献   

14.
Abstract

To assess whether grafting raised the salt tolerance of cucumber seedlings by limiting transport of Na+ to the leaf and to test whether the salt tolerance of grafted plants was affected by the shoot genotype, two cucumber cultivars (“Jinchun No. 2”, a relatively salt-sensitive cultivar, and “Zaoduojia”, a relative salt-tolerant cultivar) were grafted onto rootstock pumpkin (Cucurbita moschata Duch. cv. “Chaojiquanwang”, a salt-tolerant cultivar). Ungrafted plants were used as controls. The effects of grafting on plant growth and ion concentrations were investigated under NaCl stress. Reductions in the shoot and root dry weights, leaf area and stem diameter of grafted plants were lower and concentrations of K+ and Cl? in the leaves were higher than those of ungrafted plants under the same NaCl stress. The Na+ concentration and Na+/K+ ratio in scion leaves and in the stems of grafted plants were lower, whereas those in rootstock stems and roots were higher than in ungrafted plants under the same NaCl stress. Shoot and root dry weight, leaf area and stem diameter were negatively correlated with leaf Na+ concentrations and Na+/K+ ratio, but were positively correlated with leaf K+ concentrations. The Na+ concentrations and Na+/K+ ratio were lower, whereas the K+ concentrations in the leaves of grafted “Zaoduojia” plants were higher than those in grafted “Jinchun No. 2” plants under the same NaCl stress. The reductions in leaf area and stem diameter of grafted “Jinchun No. 2” plants were more severe than those of grafted “Zaoduojia” plants. These results indicate that: (1) the higher salt tolerance of grafted cucumber seedlings is associated with lower Na+ concentrations and Na+/K+ ratio and higher K+ concentrations in the leaves, (2) grafting improved the salt tolerance of cucumber seedlings by limiting the transport of Na+ to the leaves, (3) the salt tolerance of grafted cucumber seedlings is related to the shoot genotype.  相似文献   

15.
Physiological responses to salt stress were investigated in two cotton (Gossypium hirsutum L.) cultivars (Pora and Guazuncho) grown hydroponically under various concentrations of NaCl. Dry matter partitioning, plant water relations, mineral composition and proline content were studied. Proline and inorganic solutes were measured to determine their relative contribution to osmotic adjustment. Both leaf water potential (Ψw) and osmotic potential (Ψs)decreased in response to NaCl levels. Although Ψwand Ψs decreased during salt stress, pressure potential Ψp remained between 0.5 to 0.7 MPa in control and all NaCl treatments, even under 200 mol m?3 NaCl. Increased NaCl levels resulted in a significant decrease in root, shoot and leaf growth biomass. Root / shoot ratio increased in response to salt stress. The responses of both cultivars to NaCl stress were similar. Increasing salinity levels increased plant Na+ and Cl?. Potassium level remained stable in the leaves and decreased in the roots with increasing salinity. Salinity decreased Ca2+ and Mg2+ concentrations in leaves but did not affect the root levels of these nutrients. The K/Na selectivity ratio was much greater in the saline treated plants than in the control plants. Osmotic adjustment of roots and leaves was predominantly due to Na+ and Cl? accumulation; the contribution of proline to the osmotic adjustment seemed to be less important in these cotton cultivars.  相似文献   

16.
Effect of high NaCl concentration in the nutrient medium on transpiration, abscisic acid, cytokinin and proline content of two soybean varieties With the differentially salt-sensitive soybean varieties ?Lee”? and ?Jackson”? the effect of salinization on transpiration, Cl? and Na+ accumulation, and on abscisic acid (ABA), cytokinin and proline content was investigated. Salinization with 75 mM NaCl in the nutrient medium drastically inhibited the transpiration (about 40%) of both varieties but more so with the variety ?Jackson”?. Nevertheless this variety translocated substantially more Cl? into the shoot than ?Lee”?. However, ?Lee”? accumulated more Cl? into the roots and thus was able to effectively protect the shoot against a toxic Cl? concentration. The Na+ distribution in the roots and shoots was nearly the same in both varieties. The ABA content of the leaves of both varieties increased 5-fold to 1200 ng × g? dry weight after 48 h of salt stress. About the same time transpiration of the salt-stressed plants reached a minimum. Between 48 and 168 h the ABA content of ?Lee”? dropped to about half. The ABA level in ?Jackson”? remained higher which indicated that the shoot was stressed more intensely and/or longer. The results do not imply a causal relationship between the ABA concentration in the leaves and the exclusion of C1? from the shoot of ?Lee”?. The cytokinin concentration of the two soybean varieties was not significantly affected by salinization. The proline content in the leaves increased markedly with salt stress in both varieties but much more so in ?Jackson”?. Proline content in the leaves increased from about 1.8 μmoles × g?1 dr. w. before salt stress to 24.7 μmoles × g?1 dr. w. after 168 h of stress. However, the proline concentration dropped to nearly the initial level within 48 h after a 120 h salt stress treatment was discontinued and the plants were returned to a control solution. In ?Lee”? salinization only doubled the amount of proline found initially. The highest value was observed after 120 h of salinization.  相似文献   

17.
中亚滨藜是一种典型的盐生植物,广泛分布在我国盐碱地区。前期研究中,我们发现盐胁迫显著诱导了中亚滨藜幼苗根尖类黄酮的累积,但其中的生理机理尚不完全清楚。在不同盐浓度(50 mmol·L~(-1)、100 mmol·L~(-1)、250mmol·L~(-1)、500 mmol·L~(-1)、600 mmol·L~(-1) NaCl)处理下,通过添加KNO_3(25 mmol·L~(-1)、35 mmol·L~(-1))和外源槲皮素(100 nmol·L-1 quercetin),采用植物生理学和生物化学等研究方法,分析了盐诱导的类黄酮累积在调节中亚滨藜幼苗耐盐性中的生理机理。研究结果表明,使用外源类黄酮类物质——槲皮素进行处理,一方面更加抑制了盐胁迫下幼苗主根的生长,同时还显著降低了根部H_2O_2的累积和幼苗在盐胁迫下的MDA水平,但使可溶性糖含量显著升高。这些结果表明,槲皮素通过抑制主根生长,影响了中亚滨藜根系结构;通过降低氧化伤害,提高了中亚滨藜幼苗对盐胁迫的耐受性。盐胁迫还显著诱导了中亚滨藜幼苗对硝酸盐(NO3-)的累积,使用25mmol·L~(-1)和35 mmol·L~(-1) KNO3处理,可显著诱导其幼苗根尖类黄酮的累积。这些结果表明,硝态氮可能通过影响类黄酮途径,从而参与调控了中亚滨藜幼苗的耐盐性。本研究为进一步揭示中亚滨藜耐盐的生理与分子机制,以及类黄酮参与调控中亚滨藜耐盐性的生理与分子机理提供了理论基础;同时为使用现代生物技术和农艺措施提高作物耐盐性、改良盐碱地提供了理论依据和技术支持。  相似文献   

18.
A tub experiment was conducted to assess the effect of exogenously applied trehalose (0, 10, and 20 mM) on various attributes of two rice cultivars (Bas-385 and Bas-2000) under salt stress (0, 50, 100, and 150 mM). Salinity decreased growth, gas exchange characteristics, shoot and root potassium (K+) ions, hydrogen peroxide (H2O2), total soluble proteins, activity of catalase (CAT), and yield attributes, while it increased chlorophyll contents, shoot and root sodium (Na+) and calcium (Ca2+), malondialdehyde (MDA), glycinebetain (GB), free proline, and peroxidase (POD) activity. Foliar-applied trehalose improved growth attributes, net photosynthetic rate, GB, total soluble proteins, superoxide dismutase (SOD) and yield. Yield was not obtained at 150 mM salt stress. The rice cultivar Bas-2000 showed better performance with respect to gas exchange attributes and activities of enzymatic antioxidants. Overall, varying levels of foliar-applied trehalose proved to be effective in ameliorating adverse effects of salt stress on rice.  相似文献   

19.
Olive (Olea europaea L cv. Leccino and cv. Frantoio) plants grown in aeroponic cultivation system were supplied with Hoagland solutions containing 0 and 150 mM NaCl for 4 weeks. Sodium (Na+), chloride (Cl‐), and potassium (K+) concentration was measued on 15‐day‐old leaves and K+/Na+ selectivity ratio was calculated. Plant water relations were estimated on the same leaves by measuring leaf bulk water and osmotic potentials, and by calculating leaf turgor pressure. Root and leaf tissues were also analysed for lipid composition, estimating free sterol (FS), glycolipid (GL) and phospholipd (PL) content. The salt‐sensitive Leccino accumulated more Na+ and Cl‐ in the leaves and showed a lower K+/Na+ selectivity ratio than the salt‐tolerant Frantoio. The FS/PL ratio and the content of GL (namely mono‐galactosyldiglyceride, MGDG) in the roots were related to the salt accumulation in the shoot. Salinity‐induced changes on root lipids were more important in Frantoio than in Leccino, indicating the specific role of the roots in salt exclusion mechanisms. Conversely the effect of salinity on leaf lipid composition was more important in the leaves of the salt‐sensitive Leccino.  相似文献   

20.
Sorghum (Sorghum bicolor L.) was grown on an alkalinized plot for 90 days. Inorganic ions and compatible solutes were measured to investigate the physiological adaptations by which sorghum tolerates natural alkaline stress. Plant growth was clearly inhibited. The stress led to increased Na+ content in roots but had only a small effect on Na+ accumulation in leaves; K+ content in roots was lower than that in leaves and stems; and Na+ content and Na+/K+ ratio were much higher in roots than in leaves and stems. These suggest that maintaining a substantially higher osmotic potential in roots for greater uptake of water and restricting the spread of Na+ to shoots are physiological adaptations to alkalinity. Soluble sugar was the main osmolyte in roots, stems, and leaves; proline, amino acids, and oxalates contributed to osmotic regulation slightly, and it was noteworthy that K+ played a major role in osmotic regulation in leaves.  相似文献   

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