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1.
An experiment was conducted on five wheat ( Triticum aestivum L.) cultivars, C 306, PBW 175 (tolerant to water stress), DL 153-2 (moderately tolerant to water stress), HD 2428 and HD 2329 (recommended for irrigated conditions, susceptible to water stress), under pot culture conditions to study the effect of water stress on oxidative injury and antioxidant activity. Water stress significantly decreased relative water content (RWC), ascorbic acid content and membrane stability, and increased hydrogen peroxide and malondialdehyde content, a measure of lipid peroxidation, and activities of antioxidant enzymes in all the genotypes at 7, 17 and 27 days after anthesis (DAA). Water stress tolerant genotypes C 306 and PBW 175, closely followed by DL 153-2, were superior to HD 2428 and HD 2329 in maintaining high RWC, ascorbic acid content and membrane stability and lower hydrogen peroxide content and lipid peroxidation (malondialdehyde content) under water stress at the three stages. The highest activities of glutathione reductase and catalase under water stress were observed in C 306, PBW 175 and DL 153-2 and the lowest activities in HD 2428 and HD 2329 at all the stages. Superoxide dismutase activity at all stages under irrigated conditions and at the first and second stages under water stress conditions did not show significant variation among the different genotypes, but at the last stage under water stress the enzyme activity was highest in C 306, closely followed by PBW 175 and DL 153-2, and lowest in HD 2428 and HD 2329. It is apparent that water stress induces an increase in hydrogen peroxide content and consequently lipid peroxidation and membrane injury (reduced membrane stability). The degree of oxidative stress and antioxidant activity seems to be closely associated with the tolerance/susceptibility of a genotype to water stress.  相似文献   

2.
Two old (Huangsedadou and Longxixiaohuangpi (LX)) and two new (Jindou 19 (JD) and Zhonghuang 30 (ZH)) soya bean (Glycine max (L.) Merr.) cultivars were used to investigate the influence of soil drying on the abscisic acid (ABA) accumulation in leaves, stomatal conductance (gs), leaf water relations, osmotic adjustment (OA), leaf desiccation tolerance, yield and yield components. The greater ABA accumulation was induced by soil drying, which also inducing gs decreased at higher soil water contents (SWC) and leaf relative water content (RWC) significantly decreased at lower SWC in the new soya bean cultivars than in the old soya bean cultivars. The soil water threshold between the value at which stomata began to close and the RWC began to decrease was significantly broader in the new cultivars than in the old cultivars. The new cultivars had significantly higher OA and lower lethal leaf water potential than old cultivars when the soil dried. The old cultivars had greater biomass, but lower grain yield than the new cultivars in well‐watered, moderate stress and severe stress conditions. Thus with soil drying, the new soya bean cultivars demonstrated greater adaptation to drought by inducing greater ABA accumulation, stomatal closure at higher SWC, enhanced OA and better water relations, associated with increased leaf desiccation tolerance, greater water use efficiency and higher yield.  相似文献   

3.
Two wheat genotypes differing in water stress sensitivity (C306, relatively tolerant; HD2329, relatively susceptible) were water stressed during early grain filling by withholding water for 7 days at watery‐ripe (WR) stage and examined for water status, abscisic acid (ABA) and osmolytes in grains as well as in flag leaf (FL). Both the genotypes differed significantly from each other in endogenous levels of ABA, proline, glycine betaine, total soluble sugars, reducing sugars, sucrose and potassium. The tolerant genotype showed higher content of ABA, proline, glycine betaine, total sugars, reducing sugars and had higher water content in its FL and grains than the susceptible genotype, which contained more of glycine beatine and potassium but had lower ABA and water content in its FL and grains. Although carbohydrates constituted the major amount of all the solutes, proline and glycine betaine increased manifold during stress. Exogenous application of 2 μm ABA at 5 days after anthesis to FL of stressed plants increased the endogenous content of ABA, accelerated the accumulation of osmolytes, improved the water status of FL and grains that resulted in higher grain weight, especially in the susceptible genotype. Differential response of contrasting wheat genotypes to water stress may be governed by ABA‐dependent solute accumulation in grains and FL.  相似文献   

4.
Drought tolerance in plants is a complex trait involving morphological, physiological, and biochemical mechanisms. Hundreds of genes underlie the response of plants to the stress. For crops, selecting cultivars that can produce economically significant yields under drought is a priority. Potato (Solanum tuberosum L.) is considered as drought sensitive crop, although cultivar-dependent differences in tolerance have been described. Cultivar ‘Katahdin’ possesses many appropriate characteristics and is widely used for breeding purposes worldwide; it also has enhanced tolerance to drought stress. In this study, we evaluated cv. ‘Katahdin’ and a half-sib family of 17 Katahdin-derived cultivars for leaf relative water content (RWC) and tuber yield under drought stress. The yields of cultivars ‘Wauseon’, ‘Katahdin’, ‘Magura’, ‘Calrose’, and ‘Cayuga’ did not significantly decline under drought stress. Among these five, Wauseon exhibited the lowest reduction in both tuber yield and relative water content under water shortage. The data showed that ‘Wauseon’ is the most attractive cultivar for studies of molecular and physiological processes under drought and for potato breeding due to low yield losses that correspond with high RWC values. This cultivar can serve as a reservoir of potentially useful genes to develop cultivars with enhanced tolerance to this abiotic stress.  相似文献   

5.
Influence of sudden and gradual drought stress (DS) and foliar‐applied glycinebetaine (GB) on growth, water relations, osmolyte accumulation and antioxidant defence system were investigated in the plants of two maize (Zea mays L.) cultivars, that is, drought‐tolerant Shaandan 9 (S9) and drought‐sensitive Shaandan 911 (S911). Sudden DS caused less accumulation of GB and free proline, but a more accumulation of malondialdehyde (MDA), which resulted in a greater reduction in leaf relative water content (RWC) and dry matter (DM) in both cultivars compared with the gradual DS. Exogenous GB application caused a rise in DM, RWC, contents of GB and free proline as well as the activities of SOD, CAT and POD along with a decline in MDA content to various extent in both cultivars under both types of DS. A more pronounced effectiveness of GB application was observed in S911 than that in S9 under the same type of DS. It seemed that the more serious damage of DS was on maize plants, and the better positive role of GB was observed in terms of mitigating the adverse effects of DS. From this study, it was possible to propose that hardening for drought resistance by gradual DS treatment and GB application are effective to make plants robust to thrive under water‐deficit conditions.  相似文献   

6.
This paper reports the influence of the osmotic adjustment capacity and turgor potential (TP) on tolerance to drought in 12 cultivated genotypes, six breeding lines and six cultivars of barley (Hordeum vulgare L.) under terminal water‐stress conditions. When the crops reached the flag leaf stage, half of the experimental plots in which they were grown were submitted to water stress treatment and the remainder maintained under optimal irrigation conditions. Differences were seen in the osmotic adjustment, relative water content (RWC) and water potential (WP) of the different genotypes. Two of the breeding lines showed the greatest osmotic adjustment capacities, maintaining their TPs better than the other genotypes studied. A positive, significant correlation was found between yield and osmotic adjustment capacity, RWC and WP under water‐stress conditions. Osmotic adjustment capacity and TP were linearly related, indicating that as water stress increases osmotic adjustment favours the maintenance of higher TPs. Significant correlations were found between osmotic adjustment capacity and grain filling rate and grain yield. Under conditions of terminal water stress, yield was negatively correlated with the number of days to ear emergence; no correlation was found between osmotic adjustment capacity and earliness. Early ear emergence, a good osmotic adjustment capacity and high RWC values all contributed to yield increases under terminal water‐stress conditions.  相似文献   

7.
Recent studies on chilling tolerance mechanisms in maize revealed a significant positive correlation between genotypic chilling tolerance and chilling‐induced accumulation of the stress hormone abscisic acid (ABA) under controlled growth chamber conditions. Based on this and other results, the hypothesis was developed that chilling tolerance in maize is related to the ability to accumulate large amounts of ABA rapidly, as a protection against chilling injury. The objective of the present study was to test this hypothesis under field conditions during natural cold weather periods in spring, which often cause severe chilling injury in maize fields. In two experiments at two locations in Europe with contrasting climates, eight maize genotypes with different genotypic chilling tolerance were cultivated in spring in the field according to agronomic practice for maize. Before and at the end of cold weather periods, ABA levels and water contents were determined in the third leaves. It was found that chilling‐tolerant genotypes accumulated higher amounts of ABA during the chilling period than chilling‐sensitive genotypes. A significant positive correlation between chilling tolerance and the levels of ABA in the leaves was found. These results support the above‐mentioned hypothesis. In contrast to earlier studies performed under growth chamber conditions, the water content in chilled leaves was mostly higher than in non‐chilled leaves. The increase in ABA is therefore not attributable to chilling‐induced water deficit, but probably to the low temperature itself.  相似文献   

8.
Twelve varieties of Oat ( Avena sativa L.) were screened for relative drought tolerance based on the magnitude of chlorophyll stability index (CSI), relative water content (RWC) and free proline accumulation. IGFR1-2670, IGFRI-3021, IGFRI-2688 and IGO-8 showed a lower magnitude of CSI under stress condition in comparison to other tested varieties whereas the values of RWC and tree proline accumulation were higher. Based on the observations of this study it is concluded that, of the varieties tested, IGFRI-2670, 3021 2688 and IGO-8 are relatively more drought tolerant than the other genotypes tested. A close agreement was also noticed amongst the trends of CSI and proline accumulation, and per cent reduction in yield in rainfed over irrigated conditions.  相似文献   

9.
The study investigates the differential accumulation of osmolytes and their contribution to osmotic adjustment in leaf tissue of peanut under drought stress. Plants of four peanut cultivars, obtained from ICRISAT, with varying degrees of drought tolerance were subjected to 10, 15, and 20 days of drought stress by withholding irrigation to 20-day-old seedlings. Leaf samples were collected on 31st, 36th, and 41st days from these stressed plants along with their respective controls. The results indicated that ICGV 91114 was the most drought-tolerant variety followed by ICGS 76 and J 11, while JL 24 was the most drought susceptible. The leaves of ICGV 91114 maintained higher RWC and chlorophyll pigments under water stress compared to JL 24. The contents of all the biochemicals were found to be the maximum in ICGV 91114 and least in JL 24 during stress periods. Drought induced increase in the contents of TSS and TRS were significantly higher in ICGV 91114 under 15 days of water stress compared to the other three varieties and stress periods, while TLP, total free amino acids and total proline were higher in 20-day-old stressed plants of ICGV 91114 and the lowest in 10-day-old stressed plants of JL 24. In the control plants of all four varieties, there was a steady increase in the contents of all these biochemicals with an increase in the age of the plants. The results suggest that osmolytes act as important compatible solutes to maintain osmotic balance, to protect cellular macromolecules, and scavenge free radicals under water stress conditions.  相似文献   

10.
Plant growth and development is hampered by various environmental stresses including chilling. We investigated the possibility of improving chilling tolerance in hybrid maize by glycinebetaine (GB) seed treatments. Maize hybrid (Hycorn 8288) seeds were soaked in 50, 100 and 150 mg l?1 (p.p.m.) aerated solution of GB for 24 h and were dried back. Treated and untreated seeds were sown at 27 °C (optimal temperature) and at 15 °C (chilling stress) under controlled conditions. Germination and seedling growth was significantly hindered under chilling stress. Moreover, chilling stress significantly reduced the starch metabolism and relative water contents (RWC), and increased the membrane electrolyte leakage. However, activities of antioxidants (catalase, superoxide dismutase and ascorbate peroxidase) were increased under stress conditions. Seed treatments with GB improved the germination rate, root and shoot length, seedling fresh and dry weights, leaf and root scores, RWC, soluble sugars, α‐amylase activity and antioxidants significantly compared with untreated seeds under optimal and stress conditions. Induction of chilling tolerance was attributed to maintenance of high tissue water contents, reduced membrane electrolyte leakage, and higher antioxidant activities and carbohydrate metabolism. Seed treatment with 100 mg l?1 GB was the best treatment for improving the performance of hybrid maize under normal and stress conditions compared with control and other levels used.  相似文献   

11.
水稻品种对几种逆境的多重耐性及与ABA的关系   总被引：21，自引：3，他引：18  
从一些耐旱和耐冷品种中筛选出几个具多重耐性的品种,其中大黄谷耐渗透胁迫和盐胁迫,芝麻糯耐盐和冷胁迫,桂溪和湘中籼2号耐渗透胁迫,也较耐冷胁迫.以大黄谷、芝麻糯和桂溪为材料,研究了多重耐性与ABA积累的关系.在渗透胁迫、盐胁迫和冷胁迫下,各水稻品种内源游离ABA含量迅速积累,耐性品种积累的ABA量都较敏感品种高,  相似文献   

12.
脱落酸(abscisic acid, ABA)是一种重要的植物激素,与作物的抗干旱胁迫密切相关。本试验以灌浆期的豫麦949和陕麦5号小麦品种为试材,PEG干旱处理72 h后,比较了脱落酸对小麦相对水分含量、叶绿素、丙二醛含量以及产量的影响,并采用反转录半定量PCR方法测定PSII中psbA基因转录水平的变化。结果表明,干旱胁迫明显降低小麦叶片中相对水分和叶绿素含量,增加丙二醛含量,抑制psbA基因的转录,降低小麦的产量,而外源脱落酸能明显缓解这些胁迫反应。与豫麦949相比,陕麦5号中质膜损伤较小,相对水分和叶绿素含量、产量以及psbA基因转录水平的下降也较小,外源脱落酸处理后,各参数也能够恢复到对照水平,说明不同小麦品种的抗干旱胁迫能力与psbA基因的表达水平密切相关。本试验的研究结果也首次发现了外源ABA能够调控干旱胁迫下灌浆期小麦psbA基因的表达,稳定PSII系统中重要基因的转录水平,从而提高灌浆期小麦的抗干旱胁迫能力。  相似文献   

13.
以转IrrE基因与非转基因甘蓝型油菜为材料,用10%(W/V)PEG6000(聚乙二醇)进行了干旱胁迫实验,比较研究了转IrrE基因与非转基因甘蓝型油菜幼苗的耐受性应答情况。结果表明:转基因油菜植株含水量下降趋势小于非转基因油菜植株;转基因油菜植株叶绿素含量和荧光参数F0的上升趋势均明显大于非转基因油菜植株;转基因油菜植株的Fv/Fm值和可溶性蛋白含量均大于非转基因油菜植株,但丙二醛(MDA)含量小于非转基因油菜植株。以上结果从侧面证实了:在干旱胁迫下,转IrrE基因油菜植株较非转基因植株有更强的耐受能力;IrrE基因作为一种转录调节因子,广泛参与了油菜幼苗对干旱胁迫的耐受性应答过程,增强了植株的耐旱能力。  相似文献   

14.
为了了解不同茶树品种对干旱环境的适应性,分析了土壤水分胁迫对茶树部分渗透调节物质含量变化的影响。以茶树‘铁观音’和‘福鼎大白茶’2年生幼苗为材料,采用盆栽试验的方法,研究了在正常供水(土壤含水量为田间最大持水量的75%)、轻度水分胁迫(55%)、中度水分胁迫(35%)和重度水分胁迫(20%)条件下,茶树部分渗透调节物质的变化情况。结果表明,正常供水条件下,‘铁观音’叶片相对含水量、脯氨酸含量低于‘福鼎大白茶’,可溶性蛋白和可溶性糖含量高于‘福鼎大白茶’;水分胁迫下‘铁观音’、‘福鼎大白茶’叶片相对含水量随胁迫程度的加大而降低,可溶性蛋白质、可溶性糖以及脯氨酸的含量随胁迫程度的加大而增多,但在重度胁迫下,‘福鼎大白茶’的可溶性蛋白质及脯氨酸含量下降。在相同的水分胁迫条件下,‘铁观音’叶片相对含水量的降幅都小于‘福鼎大白茶’,而可溶性蛋白、可溶性糖和脯氨酸含量的增幅都比‘福鼎大白茶’大。表明在土壤水分胁迫下‘铁观音’的渗透调节适应能力高于‘福鼎大白茶’。  相似文献   

15.
Increase in soil temperature together with decrease in soil moisture during anthesis of spring wheat (Triticum aestivum L) crops is predicted to occur more frequently in a future climate in Denmark. The objective of this study was to investigate the responses of two Danish spring wheat varieties (Trappe and Alora) to soil warming (H), drought (D) and both (HD) during anthesis. The plants were grown in pots in a climate‐controlled glasshouse. In H, the soil temperature was increased by 3 °C compared with the control (C). In both D and HD treatments, the plants were drought‐stressed by withholding irrigation until all of the transpirable soil water had been depleted in the pots. Results showed that, particularly under D treatment, Alora depleted soil water faster than Trappe. In both varieties, flag leaf relative water content (RWC) was significantly lowered, while spikelet abscisic acid (ABA) concentration was significantly increased by D and HD treatments. Compared with the C plants, D and HD treatments significantly reduced ear number, ear to tiller ratio, shoot biomass, grain yield, harvest index and seed set but hardly affected tiller number and 1000‐kernel weight, whereas H treatment alone only decreased shoot biomass and reduced seed set. When analysed across the varieties and the treatments, it was found that the reduction in seed set was closely correlated with the increase in spikelet ABA concentration, indicating that D and HD treatments induced greater spikelet ABA concentrations might have caused seed abortion. It was concluded that the grain yield reduction under D and HD treatments during anthesis in spring wheat is ascribed mainly to a lowered seed set and wheat varieties (i.e. Alora) with more dramatic increase in spikelet ABA concentration are more susceptible to D and HD treatment.  相似文献   

16.
The effects of water stress on physiological attributes of drought‐sensitive (Kalyansona) and drought‐tolerant (C‐306) wheat cultivars were studied in a pot experiment. Water stress was imposed by withholding irrigation at boot and anthesis stages. Leaf water potential, leaf osmotic potential and leaf turgor potential (measured with pressure chamber and osmometer), as well as leaf diffusive resistance, leaf transpiration rate and leaf‐to‐air transpiration gradient (measured with a steady‐state porometer) were measured diurnally. Growth and yield parameters were recorded after harvesting of the crop. Triplicate data were analysed using a completely randomized design and correlations amongst these parameters were computed. Water stress was found to reduce diurnal leaf water potential and leaf osmotic potential in both the genotypes but leaf osmotic potential was significantly higher in the drought‐tolerant cultivar C‐306 than in the drought‐sensitive cultivar Kalyansona. Positive turgor was recorded in both the genotypes under water stress and non‐stress conditions. Water‐stressed plants showed significantly lower turgor potential than control plants. In diurnal observations, water‐stressed plants exhibited significantly higher leaf diffusive resistance in both genotypes at both stages. The diffusive resistance of C‐306 was predominantly higher than that of Kalyansona. Water stress decreased leaf transpiration rate at both stages but the reduction was higher at the anthesis stage. The leaf‐to‐air temperature gradient was much higher in C‐306 than in Kalyansona at the boot stage but at the anthesis stage genotypic variation was non‐significant. The capacity to maintain cooler foliage was lower at the anthesis stage than at the boot stage in both the cultivars. Shoot dry weight, number of grains, test weight, grain yield, biological yield and harvest index decreased to a greater extent when water stress was imposed at the anthesis stage, while imposition of water stress at the boot stage caused a greater reduction in plant height and number of tillers. Similarly, water stress caused a smaller reduction in growth, yield and yield attributes in C‐306 than in Kalyansona. In general, the correlation coefficient of grain and biological yield with water potential and its components was positive and highly significant. Similarly, turgor potential was also correlated positively and significantly with grain yield at both the stages, but with biological yield it was significant only at the anthesis stage. A negative and significant correlation was obtained for diffusive resistance and leaf‐to‐air temperature gradient with grain yield at the boot and anthesis stages. The rate of transpiration was also positively and significantly correlated to grain and biological yields at both the stages. Amongst the yield attributes, number of leaves and number of tillers were positively correlated at the anthesis stage, whereas leaf area and shoot dry weight were significantly correlated with grain and biological yields at both the stages.  相似文献   

17.
Drought tolerant and susceptible cultivars of wheat, C-306 and Kalyan sona, growing under non-stressed and water-stressed conditions, were sprayed with benzyladenine (BA) at 70 days after sowing (DAS). Observations recorded at 5, 10, 15, 20 and 25 days after spraying revealed that BA increased the rate of transpiration (TR) in C-306 under non-stressed conditions. However, under water stress, the increase was significant only after 5 days of BA spraying. In Kalyan sona BA treatment either decreased TR or did not exhibit significant increase under non-stressed conditions, but caused significant increase in TR under water stress. The increase in TR was elicited through enhanced stomatal opening. Water potential, osmotic potential and pressure potential of both genotypes decreased on account of water stress. The effect of BA was not perceptible on restoration of leaf water potential (LWP) or its components. The effect of BA was possibly confined to stomatal behaviour and transpiration.  相似文献   

18.
为了揭示蒲公英在干旱胁迫下渗透调节和酶保护系统的作用机理以及质膜水孔蛋白PIP2-3基因的表达特征,采用盆栽控水试验,研究了不同干旱胁迫RWC=(90±5)%、RWC=(75±5)%、RWC=(50±5)%下蒲公英渗透调节物质、酶保护系统以及质膜水孔蛋白基因的相关表达。结果表明:随着干旱胁迫的加重,蒲公英叶片中的可溶性糖、可溶性蛋白、游离脯氨酸的含量显著增加,超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)的活性显著提高,在轻度胁迫(MS)中呈持续上升的趋势,重度胁迫(SS)中则呈现先升高后下降的趋势(可溶性糖除外);质膜水孔蛋白PIP2-3基因的相对表达量上调,轻度胁迫(MS)显著高于重度胁迫(SS)。复水7 d后,渗透调节物质的积累以及SOD的含量下降,但仍显著高于CK,POD、CAT的含量以及质膜水孔蛋白PIP2-3基因的相对表达量恢复正常,说明在干旱胁迫条件下蒲公英通过增加渗透调节物质的积累,提高酶保护系统的活性来增强植株的抗逆性,上调质膜水孔蛋白基因的相对表达量来加强水分运输能力。  相似文献   

19.
In four wheat ( Triticum aestivum L.) cultivars of tall (C306 and Narmada) and dwarf (HD2329 and Kundan) type, post-anthesis water stress affected the dry matter accumulation in plant parts with respect to main shoot controls. HD2329 among the dwarf types and Narmada 112 among the tall types were more adversely affected by stress, with greater reductions in their biomass and grain yield. Of the tolerant types, C306 (tall) showed a marginal reduction while Kundan (dwarf) had no reduction in these parameters as a result of stress. The results also indicated a varietal response to carbon and nitrogen accumulation and their partitioning in the main shoot when subjected to post-anthesis stress. In the susceptible dwarf cultivar HD2329, and in the susceptible tall cultivar Narmada 112, carbon and nitrogen contents were reduced in the grains of stressed main shoots. Of the tolerant cultivars, the dwarf type Kundan was not affected by stress, while the tall type C306 registered an increase in carbon content and its partitioning to grain.  相似文献   

20.
【研究目的】为分析玉米ABA/逆境响应转录因子ABP9基因过量表达对植物生长发育的影响以利用该基因开展抗逆分子育种。【方法】本研究构建了35S启动子驱动ABP9组成型表达的植物表达载体，获得了过表达ABP9基因的拟南芥转基因株系，并在正常生长条件下，比较了转基因植株和野生型在种子萌发、营养生长和生殖生长阶段的形态和生理变化，分析了可能的分子机制。【结果】结果表明，正常生长条件下，转基因植株与野生型相比表现出萌发，幼苗生长以及开花阶段的生长抑制；气孔开度减小，叶片内源ABA含量降低；ABA信号传导基因表达增强，而ABA合成基因表达降低；而且这些效应在ABP9基因表达相对较强的转基因株系中表现更明显。【结论】说明ABP9基因过量在正常生长条件下即诱导转基因植株产生耐逆反应，抑制植株的生长发育。因此，在利用ABP9基因进行转基因抗逆育种时须考虑控制ABP9基因适时适量表达。  相似文献   

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