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1.
干旱胁迫降低大豆产量,探究提高大豆耐旱能力和降低产量损失的机制对大豆生产具有重要意义。施褪黑素能缓解干旱胁迫对植株生长的抑制和氧化损伤。本试验于2017—2018年研究叶面喷施褪黑素对干旱胁迫下大豆鼓粒期叶片光合、抗逆、碳氮代谢和产量的影响表明,外源褪黑素提高干旱胁迫下大豆叶片抗氧化酶活性,抑制活性氧的产生和细胞膜损伤,缓解干旱胁迫对光合能力的抑制,提高碳氮同化能力,最终缓解干旱胁迫造成的产量损失。与干旱胁迫相比,褪黑素处理下单株荚数、单株粒数和百粒重两年平均提高了2.9%、0.8%和17.2%,产量(单株粒重)平均提高了14.7%。  相似文献   

2.
Balanites aegyptiaca is a drought‐tolerant tree naturally distributed in Africa and has a high potential for biofuel production and livelihood. To understand the plant tolerance to drought stress, B. aegyptiaca plants collected from five provenances were subjected for 4 weeks to drought stress through different regimes of soil volumetric water content (VWC, i.e. 25% control, 15% as moderate and 5% as a severe drought stress) followed by 2‐week recovery. Morpho‐physiological responses as well as the changes in antioxidant defences under water stress and recovery were investigated. Drought stress significantly reduced plant biomass‐related parameters, stomatal conductance, quantum efficiency and increased leaf temperature. Each provenance showed specific patterns of stress response reactions that were detected in a cluster analysis. The large leaf area and a high level of lipid peroxidation in Cairo provenance increased its sensitivity to severe drought. For provenances El‐Kharga and Yemen, the highest tocopherol contents and the highest catalytic activities of ascorbate peroxidase (SOD), catalase (CAT), glutathione reductase (GR) and dehydroascorbate reductase (DHAR) were recorded. These traits contributed to the high drought tolerance of these two provenances in comparison with the other provenances. All plants recovered from stress and showed specifically increased activity of glutathione‐S‐transferase (GST) as a repair mechanism. Results showed that the drought tolerance level in B. aegyptiaca is provenance‐dependent.  相似文献   

3.
Drought is a severe abiotic stress and the major constraint on wheat (Triticum aestivum L.) productivity world wide. Deciphering the mechanisms of drought tolerance is a challenging task because of the complexity of drought responses, environmental factors and their interactions. The objective of this study was to evaluate the ability of the antioxidative defence system in imparting tolerance against drought‐induced oxidative stress and yield loss in two wheat genotypes, when subjected to long‐term field drought. Drought resulted in an increase in H2O2 accumulation and lipid peroxidation and decrease in ascorbate level in roots and leaves at different plant developmental stages. Drought‐tolerant genotype having higher antioxidative enzymes activities, and ascorbate level was superior to that of sensitive genotype in maintaining lower H2O2 content and lipid peroxidation and higher growth, yield and yield components under water deficit. Various antioxidative enzymes showed positive correlation with ascorbate and negative with H2O2 content. In developing grains, antioxidative defence response was nearly similar among both the genotypes under control condition; however, sensitive genotype failed to modulate the activities of antioxidative enzymes according to the ROS rush under field drought. Poor capacity of the antioxidative defence system in vegetative and reproductive tissues of sensitive genotype seems to be responsible, at least partly, for reduced yield potential under water deficit.  相似文献   

4.
大豆叶片旱促衰老及其与膜脂过氧化的关系   总被引：43，自引：3，他引：43  
许长成  邹琦 《作物学报》1993,19(4):359-364
干旱导致大豆叶片叶绿素和可溶性蛋白质含量下降,膜透性增加。不同叶位比较以生理老叶受影响较大。分析表明,干旱条件下叶片膜脂过氧化作用加强,H_2O_2累积,过氧化物酶活性提高;而活性氧清除系统的超氧化物歧化酶和过氧化氢酶活性以及抗坏血酸和还原型谷胱甘肽水平降低。干旱6天不同叶位叶间以生理老叶具较高的丙二醛和H_2O_2  相似文献   

5.
The effects of salt stress on protein (PROT) content, lipid peroxidation, proline accumulation, chlorophyll (Chl) content, and superoxide dismutase (SOD; EC 1.15.1.1), catalase (EC 1.11.1.6) and peroxidase (EC 1.11.1.7) activity were studied in the leaves and roots of canola (Brassica napus L. cv. Okapi). Four weeks after sowing (at the V4 stage), plants were exposed to salt stress by the application of NaCl solution (200 mm ) for 6 days daily, After 6 days followed by foliar application of ascorbic acid (AsA) solution (25 mm ). The activity of all the antioxidant enzymes assayed (except SOD in the roots) was increased significantly in the plants under conditions of salt stress. The application of AsA decreased enzyme activity in the leaves, but it had no effect on enzyme activity in the roots. The total PROT content of the leaves and roots decreased under the conditions of high salinity. AsA treatment of plants under salt stress increased the total PROT content significantly in both leaves and roots. Measurement of the malondialdehyde content of leaves and roots showed that lipid peroxidation was increased by interaction with damaging reactive oxygen species during salt stress, and that application of AsA reduced lipid peroxidation only in the leaves. The Chl content was also affected by salt stress. There was significant difference between the controls and salt‐stress treatments in Chl content. The results of the present study indicate that usage of AsA reduces the harmful effects of salinity and increases resistance to salinity in canola plant.  相似文献   

6.
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7.
Water deficit is perhaps the most severe threat to sustainable crop production in the conditions of changing climate. Researchers are striving hard to develop resistance against water deficit in crop plants to ensure food security for the coming generations. This study was conducted to establish the role of fulvic acid (FA) application in improving the performance of hybrid maize (Zea mays L.) under drought. Maize plants were grown under normal conditions till tasselling and were then subjected to drought by cessation of water followed by foliar application of FA (1.5 mg l?1). Drought stress disrupted the photosynthetic pigments and reduced the gas exchange leading to reduction in plant growth and productivity. Nonetheless, exogenous FA application substantially ameliorated the adversities of drought by sustaining the chlorophyll contents and gas exchange possibly by enhanced levels of antioxidant enzyme (superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT)) activities and proline. These beneficial effects yielded in terms of plant growth and allometry, and grain yield. It is interesting to note that FA application also improved the crop performance under well‐watered conditions. Hence, FA may be applied to improve the crop performance under drought and well‐watered conditions.  相似文献   

8.
Betaine aldehyde dehydrogenase (BADH) catalyses the oxidation of betaine aldehyde to glycine betaine. To test whether BADH can increase drought tolerance in soybean (Glycine max), BADH from the drought‐tolerant plant Atriplex canescens (AcBADH) was introduced into the soybean cultivar ‘Jinong 17’ by Agrobacterium‐mediated cotyledon transformation. Eight independent AcBADH transgenic lines were subjected to drought stress. As expected, AcBADH was expressed in transgenic soybean leaves and not in the control. In transgenic plants, AcBADH expression increased following drought treatment. Under osmotic stress, the germination index was 6%–17% higher in the transgenic lines than in the control. Using a randomized block design, we measured drought‐related physiological indices and yield traits. The proline content in AcBADH transgenic soybeans increased by 12.5%–16.6%, peroxidase activity increased by 1%–7%, dry weight of plant increased by 15%–20% and malondialdehyde contents decreased by 1.5%–13%, compared to the control. Under drought conditions, two of the eight transgenic soybean lines had higher yields than the control, with increases of 7.59%–8.84%. Therefore, transgenic expression of AcBADH may provide a promising strategy to engineer drought tolerance without adverse consequences.  相似文献   

9.
Effects of nitrogen rates and water stress (WS) on production, lipid peroxidation and antioxidative enzyme activities in two maize (Zea mays L.) genotypes were assessed at different stages under two levels of water supply conditions. WS caused a significant decline in dry matter, grain yield and activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) whereas a marked rise in malondialdehyde (MDA) concentration was observed in leaves for the two genotypes. However, the responses of the two varieties to WS were different: significantly higher dry matter, grain yield and antioxidative enzyme activities and lower MDA content were observed for Shaandan 9 than Shaandan 911, therefore the former could be treated as a drought tolerance variety comparatively. A better correlation was obtained amongst dry matter, grain yield and physiological traits. The addition of nitrogen increased dry matter and grain yield as well as activities of SOD, POD and CAT to different levels and significantly decreased MDA content under WS. These effects were higher for Shaandan 911 than for Shaandan 9. Furthermore, a significant effect was found for Shaandan 911 between N rates for all traits unlike Shaandan 9. Hence, we suggest that nitrogen should be applied to a water‐sensitive variety to bring out its potential fully under drought.  相似文献   

10.
Brassinolides (BRs) are naturally occurring substances, which modulate plant growth and development events and have been known to improve the crop tolerance to abiotic stresses. In this study, possible role of exogenously applied brassinolide (BR) in alleviating the detrimental effects of drought in maize was evaluated in a rain‐protected wire‐house. Maize was subjected to drought at the start of tasseling for 6 days by withholding water application followed by foliar spray of BR (0.1 mg l?1) to assess the changes in growth, gas exchange, chlorophyll contents, protein, relative leaf water contents (RLWC), proline, malonialdehyde (MDA) and enzymatic antioxidants. Drought substantially reduced the maize growth in terms of plant height, leaf area and plant biomass. Moreover, substantial decrease in gas exchange attributes (net photosynthetic rate (A), transpiration rate (E), stomatal conductance (gs), water use efficiency (WUE), instantaneous water use efficiency (WUEi) and intercellular CO2 (Ci) was also recorded. However, exogenous application of BR remarkably improved the gas exchange attributes, plant height, leaf area, cobs per plant, seedling dry weight both under drought and well‐watered conditions. BR‐induced promotion in growth and physiological and metabolic activities were mediated through increased protein synthesis enabling maintenance of tissue water potential and activities of antioxidant enzymes lowering the lipid peroxidation under drought.  相似文献   

11.
Drought stress and zinc (Zn) deficiency are serious abiotic stress factors limiting crop production in Turkey, especially in Central Anatolia. In this study, the effects of Zn deficiency and drought stress on grain yield of 20 wheat cultivars (16 bread wheat, Triticum aestivum; four durum wheat, Triticum durum cultivars) were investigated over 2 years under rainfed and irrigated conditions in Central Anatolia where drought and Zn deficiency cause substantial yield reductions. Plants were treated with (+Zn: 23 kg Zn ha−1, as ZnSO4·7H2O) and without (−Zn) Zn under rainfed and irrigated conditions. Both Zn deficiency and rainfed treatments resulted in substantial decreases in grain yield. Significant differences were determined between both bread wheat and durum wheat cultivars in terms of drought stress tolerance. Considering drought sensitivity indices over 2 years, the bread wheat cultivars Yayla‐305, Gerek‐79, Dagdas‐94 and Bolal‐2973 were found to be more drought‐tolerant than the other cultivars under both −Zn and +Zn treatments. Especially the durum wheat cultivars Cakmak 79 and Selcuklu 97 showed much greater drought susceptibility under Zn deficiency, and irrigation alone was not sufficient to obtain satisfying grain yield without Zn application. The results indicate that sensitivity to Zn deficiency stress became more pronounced when plants were drought‐stressed. The effect of irrigation on grain yield was maximized when Zn was adequately supplied, leading to the suggestion that efficient water use in Central Anatolia seems to be highly dependent on the Zn nutritional status of plants.  相似文献   

12.
Salinity stress causes ion toxicity and osmotic imbalances, leading to oxidative stress in plants. Arbuscular mycorrhizae (AM) are considered bio‐ameliorators of saline soils and could develop salinity tolerance in crop plants. Pigeonpea exhibits strong mycorrhizal development and has a high mycorrhizal dependency. The role of AM in enhancing salt tolerance of pigeonpea in terms of shoot and root dry weights, phosphorus and nitrogen contents, K+ : Na+, Ca2+ : Na+ ratios, lipid peroxidation, compatible solutes (proline and glycine betaine) and antioxidant enzyme activities was examined. Plants were grown and maintained at three levels of salt (4, 6 and 8 dSm?1). Stress impeded the growth of plants, led to weight gain reductions in shoots as well as roots and hindered phosphorus and nitrogen uptake. However, salt‐stressed mycorrhizal plants produced greater root and shoot biomass, had higher phosphorus and nitrogen content than the corresponding uninoculated stressed plants. Salt stress resulted in higher lipid peroxidation and membrane stability was reduced in non‐AM plants. The presence of fungal endophyte significantly reduced lipid peroxidation and membrane damage caused by salt stress. AM plants maintained higher K+ : Na+ and Ca2+ : Na+ ratios than non‐AM plants under stressed and unstressed conditions. Salinity induced the accumulation of both proline and glycine betaine in AM and non‐AM plants. The quantum of increase in synthesis and accumulation of osmolytes was higher in mycorrhizal plants. Antioxidant enzyme activities increased significantly with salinity in both mycorrhizal and non‐mycorrhizal plants. In conclusion, pigeonpea plants responded to an increased ion influx in their cells by increasing the osmolyte synthesis and accumulation under salt stress, which further increased with AM inoculation and helped in maintaining the osmotic balance. Increase in the antioxidant enzyme activities in AM plants under salt stress could be involved in the beneficial effects of mycorrhizal colonization.  相似文献   

13.
干旱是黑龙江省最主要的农业气象灾害之一。为明确大豆对干旱的响应机制,利用田间控水试验,研究播种出苗期和开花结荚期大豆在各干旱胁迫等级下各性状的生育特点。结果表明,播种出苗期大豆在干旱胁迫下,出苗缓慢;株高和地上、地下干物质、株荚数、株籽粒重明显偏低,空荚率偏高,其中重度胁迫空荚率比无胁迫大豆高99%;开花结荚阶段大豆遭遇中度以上干旱,光合量减少,植株相对矮小,而空荚率高,其中重度胁迫比无胁迫高81%以上;大豆花荚期是水分的敏感期,即轻度干旱也会造成较差的产量表现。大豆播种出苗期遭遇干旱胁迫后产量偏低,主因是出苗率低、生育期短,株籽粒重低和空荚率高是次要原因;光合量少、株荚数与株籽粒重下降,且空荚率高是开花结荚期产量低的综合结果。  相似文献   

14.
Due to high costs of irrigation, limited availability of irrigation water in many locations and/or lack of irrigation capabilities, genetic improvement for drought tolerance is an effective method to reduce yield loss in soybean [Glycine max (L.) Merr.]. Slow wilting and minimal yield reduction under drought are important traits in evaluating drought tolerance. Two maturity group III soybean plant introductions (PIs, PI 567690 and PI 567731) and two elite cultivars (DKB38‐52 and Pana) were evaluated with and without irrigation on a sandy soil. Drought was imposed by withholding irrigation at full bloom and continued until moderate wilting was shown by the fast leaf wilting in the check cultivar, Pana. Then, irrigation was resumed until maturity. Genotypes were scored for leaf wilting during the stress period, and yields were assessed at the end of the growing season and used to calculate a drought index. Yields of the exotic PIs were lower than those of the checks under both drought and well‐watered conditions. However, the PIs exhibited significantly lower wilting and less yield loss under drought (higher drought index) than check cultivars. The two PIs may have useful genes to develop drought‐tolerant germplasm and cultivars and maybe useful in genetic and physiological studies to decipher mechanisms responsible for improving yield under limited water availability.  相似文献   

15.
以玉米品种郑单958为材料,研究了不同程度干旱胁迫与复水条件下乙烯促进与抑制剂处理对春玉米生长、叶片保护酶系活性变化及其对膜脂过氧化作用的影响。结果表明：（1）乙烯利有利于控制玉米的株高,并提高轻度干旱条件下玉米的根重和生物量,而AgNO3（硝酸银）处理的玉米在轻度与重度干旱条件下,生物量明显降低。（2）乙烯利处理可明显抑制水分胁迫条件下玉米MDA（丙二醛）的合成,降低相对电导率,提高可溶性蛋白含量,而AgNO3处理的效果则与乙烯利刚好相反。（3）乙烯利处理可明显提高SOD（超氧化物酶）、CAT（过氧化氢酶）和POD（过氧化物酶）的活性,而AgNO3处理在一定程度上抑制SOD、CAT和POD的活性。  相似文献   

16.
The chickpea (Cicer arietinum L.) is usually grown under rainfed, rather than irrigated conditions, where drought accompanied by heat stress is a major growth constraint. The aim of this study was to select chickpea genotypes having resistance to drought/heat stress and to identify the most appropriate selection criteria for this. A total of 377 chickpea accessions were sown 2 months later than normal for the Antalya region (Turkey) to increase their exposure to the drought and high‐temperature conditions of a typical summer in this part of the world. Interspersed between every 10 test genotypes as benchmark genotypes, were plants of the two known genotypes ILC 3279 (drought‐susceptible) and ILC 8617 (drought‐susceptible), while ICC 4958 (known drought‐resistant) and ICCV 96029 (known very early, double‐podded) were also sown for confirmation. All plants were subsequently screened for drought and heat stress resistance. Soon after the two known susceptible genotypes had died, evaluations of the entire trial were made visually on a scale from ‘1’ (free from drought/heat damage) to ‘9’ (all plants died from drought/heat). Yield loss in many of the test genotypes and in the two known susceptible genotypes (ILC 3279 and ILC 8617) rose to 100 %. The desi chickpeas (smaller, dark seeds) were generally more drought‐ and heat‐resistant than the kabuli chickpeas (larger, pale seeds). Two desi chickpeas, ACC 316 and ACC 317, were selected for drought and heat (>40 °C) resistance under field conditions. Seed weight was the trait least affected by adverse environmental conditions and having the highest heritability, and it should be used in early breeding selections. When breeding drought‐ and heat‐resistant chickpeas, path and multivariate analyses showed that days to the first flowering and maturity to escape terminal drought and heat stresses should be evaluated ahead of many other phenological traits, and harvest index, biological yield and pods per plant for increased yield should also be considered.  相似文献   

17.
To study the effects of early drought priming at 5th‐leaf stage on grain yield and nitrogen‐use efficiency in wheat (Triticum aestivum L.) under post‐anthesis drought and heat stress, wheat plants were first exposed to moderate drought stress (drought priming; that is, the leaf water potential reached ca. ?0.9 MP a) at the 5th‐leaf stage for 11 days, and leaf water relations and gas exchange rates, grain yield and yield components, and agronomic nitrogen‐use efficiency (ANUE ) of the primed and non‐primed plants under post‐anthesis drought and heat stress were investigated. Compared with the non‐primed plants, the drought‐primed plants possessed higher leaf water potential and chlorophyll content, and consequently a higher photosynthetic rate during post‐anthesis drought and heat stress. Drought priming also resulted in higher grain yield and ANUE in wheat under post‐anthesis drought and heat stress. Drought priming at vegetative stage improves carbon assimilation and ANUE under post‐anthesis drought and heat stress and their combination in wheat, which might be used as a field management tool to enhance stress tolerance of wheat crops to multiple abiotic stresses in a future drier and warmer climate.  相似文献   

18.
干旱胁迫下PEPC过表达增强水稻的耐强光能力   总被引：1，自引：0，他引：1  
以过表达磷酸烯醇式丙酮酸羧化酶(PEPC)的水稻为材料,研究了不同程度干旱胁迫下开花期剑叶光合作用的光响应过程、叶绿素荧光参数、色素含量和活性氧代谢。结果表明,在干旱特别是重度干旱胁迫下,野生型水稻在强光下净光合速率迅速下降,而转Zmppc基因水稻没有明显的下降现象; 而且表示光化学活性的叶绿素荧光参数Fv/Fm、ΦPSⅡ和qP下降程度低,说明PEPC增强了干旱胁迫下水稻抵御强光胁迫的能力。这可能是因为干旱胁迫下转Zmppc基因水稻玉米黄质含量高,光系统对过剩光能的耗散能力强,能够保护光系统免受过剩光能的伤害,从而减小O2?产生速率; 同时干旱胁迫下转PEPC基因水稻抗氧化酶SOD、POD和CAT活性高,能有效清除活性氧,减轻膜质过氧化。  相似文献   

19.
外源腐胺对干旱胁迫下小麦叶片渗透调节的影响   总被引：6，自引：0，他引：6  
用15%聚乙二醇（PEG-6000）模拟干旱胁迫处理,研究外源腐胺对干旱胁迫下冬小麦幼苗叶片膜质过氧化和有机渗透调节物质的影响。结果表明：在干旱胁迫条件下,外源腐胺显著提高了冬小麦叶片可溶性糖（SS）、游离脯氨酸（Pro）、游离氨基酸（TFA）含量,分别为干旱胁迫处理的1.73倍,9.51倍,1.5倍;降低了冬小麦叶片丙二醛（MDA）含量和质膜透性（PMP）,与干旱胁迫处理相比下降了82%和84.5%,显著降低了叶片膜质过氧化程度。这说明外源腐胺能改善冬小麦幼苗叶片干旱胁迫下的渗透调节能力,从而增强植株的耐旱性。  相似文献   

20.
Barley (Hordeum vulgare L.) is an important winter cereal crop grown in the semiarid Mediterranean, where late‐terminal drought stress during grain filling has recently become more common. The objectives of this study were to investigate the growth performance and grain yield of four barley cultivars under late‐terminal drought stress under both glasshouse and field conditions. At grain filling, four barley cultivars (Rum, ACSAD176, Athroh and Yarmouk) were exposed to three watering treatments: (1) well‐watered [soil maintained at 75 % field capacity (FC)], (2) mild drought stress at 50 % FC, (3) severe drought stress at 25 % FC in the glasshouse experiment and (1) well‐watered (irrigated once a week), (2) mild drought (irrigated once every 2 weeks), (3) severe drought (non‐irrigated; rainfed) in the field. As drought stress severity increased, gross photosynthetic rate, water potential, plant height, grain filling duration, spike number per plant, grain number per spike, 1000‐grain weight, straw yield, grain yield and harvest index decreased. In the glasshouse experiment, the six‐row barley cultivars (Rum, ACSAD176, and Athroh) had higher grain yield than the two‐row barley cultivar (Yarmouk), but the difference was not significant among the six‐row cultivars under all treatments. In the field experiment, Rum had the highest grain yield among all cultivars under the mild drought stress treatment. The two‐row cultivar (Yarmouk) had the lowest grain yield. In general, the traditional cultivar Rum had either similar or higher grain yield than the other three cultivars under all treatments. However, the yield response to drought differed between the cultivars. Those, Rum and ACSAD176, that were capable of maintaining a higher proportion of their spikes and grains per spike during drought also maintained a higher proportion of their yield compared with those in well‐watered treatment. In conclusion, cultivar differences in grain yield were related to spike number per plant and grain number per spike, but not days to heading or grain filling duration.  相似文献   

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