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1.
Low temperature seriously depresses seed germination and seedling growth in winter wheat (Triticum aestivum L.). In this study, wheat plants were sprayed with abscisic acid (ABA) and fluridone (inhibitor of ABA biosynthesis) at 19 days after anthesis (DAA) and repeated at 26 DAA. The seeds of those plants were harvested, and seed germination and offspring's seedling growth under low temperature were evaluated. The results showed that exogenous ABA application decreased seed weight and slightly reduced seed set and seed number per spike. Under low temperature, seeds from ABA‐treated plants showed reduced germination rate, germination index, growth of radicle and coleoptile, amylase activity and depressed starch degradation as compared with seeds from non‐ABA‐treated plants; however, activities of the antioxidant enzymes in both germinating seeds and seedling were enhanced from those exposed to exogenous ABA, resulting in much lowered malondialdehyde (MDA) and H2O2 concentrations and production rate. In addition, the maximum quantum efficiency of photosystem II was also enhanced in ABA‐treated offspring's seedlings. It is concluded that exogenous ABA treatment at later grain‐filling stage could be an effective approach to improve cold tolerance of the offspring during seed germinating and seedlings establishment in winter wheat.  相似文献   

2.
Polyamines (PAs) are ubiquitous biogenic amines that play important roles in the environmental stress tolerance of crops. However, the relationship between PAs and plant waterlogging (WL) tolerance has received little attention. In this study, the protective effects of spermidine (Spd) against WL stress were investigated by Zea mays. WL treatment inhibited root growth and caused a significant increase in lipid peroxidation, membrane permeability and DNA damage in maize roots. Pre‐soaking seeds with Spd markedly alleviated these effects caused by WL. Spd pre‐soaking also significantly increased the endogenous Spd content in both control and waterlogged maize roots. In addition, the activity of antioxidant enzymes (catalase, CAT; glutathione reductase, GR; superoxide dismutase, SOD; peroxidase, POD) was enhanced in Spd‐pre‐soaked maize roots under WL stress. Thus, hydrogen peroxide (H2O2) and superoxide‐radical () accumulation were reduced. Spd treatment also enhances the expression and protein abundance of heat shock protein (HSP) 70 and 90 during the period of WL stress. Furthermore, Spd pre‐soaking reversed the inhibition effect of WL on H+ efflux and K+ influx in maize roots. The PM H+‐ATPase activity in Spd‐pre‐treated seedlings exhibited less inhibitory under WL conditions. In conclusion, this study suggests that WL stress could be alleviated by priming seeds with Spd in maize species. This alleviative effect was partially attributable to (i) up‐regulated activity of antioxidant enzymes; (ii) maintained PM H+‐ATPase activity; and (iii) increased Hsp70 and Hsp90 gene expression and protein abundance.  相似文献   

3.
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   

4.
We investigated the leaf : stem partitioning of winter wheat (Triticum aestivum L. varieties ‘Dekan’ and ‘Batis’) with and without drought influence. Irrigated and drought‐stressed winter wheat, grown in a rainout shelter in 2009/10 and 2013/14, were sampled during shoot elongation phase at the experimental Farm Hohenschulen located in Northern Germany. The data set contains leaf (DML) and stem dry masses (DMS), as well as measured water contents for several soil layers. A reduced relative dry matter allocation to leaves was observed under drought stress. Our results clearly show that, if simulated leaf : stem partitioning is not sensitive to drought, this will cause a positive bias in simulated leaf and a negative bias in simulated stem dry matter under water‐limited conditions. This is in accordance with previous studies which revealed that crop simulators often overestimate the impact of drought on light‐use efficiency, whereas the consequences on leaf area development are underestimated. However, the drought stress‐induced shift in leaf : stem partitioning is yet not considered by most common wheat crop simulators. Our aim was to fill the gap in simulation of drought stress implications on leaf area development. A simple allometric model for leaf : stem partitioning () was parameterized. Starting from the allometric leaf : stem relationship observed under optimum water supply, a correction term was introduced, which allows to adapt the partitioning to drought stress conditions. The lg‐transformed root‐weighted soil water potential in the rooting zone (lgψroot, lg(hPa)), calculated as a function of measured water contents and simulated root distribution, was used as a drought stress indicator. The linear correction term assumes an increase of the stem fraction, proportional to the difference between lgψroot and a drought stress threshold (pFcrit, lg(hPa)). The analysis revealed that the shift in allometric partitioning towards stem fraction starts with lgψroot greater than 1.92 [lg(hPa)]. The slope of the relative increase of dry matter allocated to the stem fraction was determined with 0.26 [lg(hPa)?1]. Both parameters of the correction term were found to be highly significant. Implications for crop modelling are discussed.  相似文献   

5.
抗冷与不抗冷水稻在低温期间叶片ABA与GA1水平变化的差异   总被引：9，自引：0，他引：9  
采用抗冷性强的东乡野生稻（东野）和对低温敏感的６２２５两个籼稻品种。发现稻苗的抗冷性与低温期间内源脱落酸（ＡＢＡ）含量上升及赤霉素（ＧＡ１）含量下降均有密切关系。东野的抗冷性比６２２５强,可能是因为其内涵ＡＢＡ、ＧＡ１水平对低温的响应比６２２５迅速,东野的ＡＢＡ／ＧＡ１比值在低温２４ｈ时就已达到最大值,而６２２５直到低温１２０ｈ才上升到最大值。  相似文献   

6.
In recent years, rising competition for water coupled with new environmental regulations has exerted pressure on water allocations for turfgrass irrigation. In this article, we reviewed published scientific and industry evidence on the agronomic and environmental impacts of turfgrass irrigation using a robust systematic review methodology. Our focus was on the links between (i) irrigation management (amount and frequency), (ii) agronomic responses to irrigation (turf quality, growth rates and rooting) and (iii) environmental impacts (nitrogen leaching). Based on an initial screening of 653 studies and data extracted from 83 papers, our results show that in most cases, under moderate levels of deficit irrigation (50%–60% of actual evapotranspiration), turf quality can be maintained at an acceptable level but with lower water consumption compared to irrigating back to field capacity. Irrigation beyond field capacity was found to increase the risk of nutrient leaching. However, evidence also showed that the concentration and total loss of in leachate were influenced more by nitrogen (N) rates, soil characteristics, turfgrass species and turfgrass growth rates than by irrigation practices. Our analyses suggest that turfgrass irrigation should be scheduled to apply water at moderate levels of deficit irrigation, sufficient to maintain turfgrass quality but limited to promote a deep and extensive rooting system. The findings provide new insights and valuable evidence for both scientists and practitioners involved in turfgrass research and management.  相似文献   

7.
A field trial conducted on the melon cultivar Huanghemi irrigated with saline water was carried out in Minqin County in the 2‐year period, 2007 and 2008. In three irrigation treatments, different saline water concentrations were applied, that is 0.8 g l?1 (Control C), 2 g l?1 (Treatment S1) and 5 g l?1 (Treatment S2), reproducing the natural groundwater concentration in the county. The electrical conductivity of the saline water was as follows: 1.00, 2.66 and 7.03 dS m?1, respectively. The aims of the study were (i) to monitor water consumption and water potential, (ii) assess, during the whole crop cycle, some growth parameters and their relations for estimating the morpho‐functional plant response irrigated with saline water and (iii) determine the ion concentration in different plant tissues to evaluate which mechanism the plant activates in the presence of high salt concentrations. Under salinity stress, the plants sustained the concentration of Ca, Mg and K, but at a level not sufficient to limit the Na adsorption. Therefore, the melon yield decreased and it was determined by a displacement of the ratio K/Na and by a lower (total potential MPa). Consequently with increasing salinity, a significant reduction was observed in: water consumption (ET c, mm), leaf area duration (LAD, m2 d), on shoot dry weight aboveground (W , g plant?1), on specific leaf area (SLA, cm2 g?1) and on leaf area ratio (LAR, cm2 g?1). In treatment S2, in addition to these changes which mainly affected the plant morphology with effects on the biomass produced, a moderate reduction was also observed in net assimilation rate (NAR, g m?2 d?1), water use efficiency (WUE), a significant reduction in the energy conversion efficiency (ECE, %) and, in short, in a reduction in the relative growth rate (RGR, g g?1 d?1).  相似文献   

8.
低温冷害影响水稻生理功能变化,如光合作用、呼吸作用、矿质养分吸收、膜脂过氧化以及抗氧化系统。本研究一方面详细介绍了低温胁迫下,光合作用、呼吸作用、矿质养分吸收、膜脂过氧化以及抗氧化系统变化机制,着重分析了低温胁迫下,水稻体内脱水蛋白、酶蛋白、活性氧、内源激素以及细胞膜脂肪酸组分的变化相关生理机制;另一方面,从冷害调控角度出发,较全面地综述了外源植物生长调节剂在水稻冷害调控方面研究概况,提出中国在水稻冷害研究领域的未来发展方向与新趋势,进而为今后水稻冷害相关研究提供理论依据。  相似文献   

9.
Abiotic stresses, including chilling, impede the plant growth and development mainly by oxidative damage. In this study, seed priming with CaCl2 was employed to reduce the damage caused by chilling stress in hybrid maize. Maize hybrid (Hycorn 8288) seeds were soaked in 50, 100 and 150 mg l−1 (ppm) aerated solution of CaCl2 for 24 h and dried. Treated and untreated seeds were sown at 27 °C (optimal temperature) and 15 °C (chilling stress) under controlled conditions. Seed priming with CaCl2 significantly reduced the chilling damage and improved the germination rate, root and shoot length, and seedling fresh and dry weights. Activities of antioxidants, including catalase, superoxide dismutase and ascorbate peroxidase, were also improved. Soluble sugars and α-amylase concentrations determined as general metabolic indicators of stress were also increased by seed priming with CaCl2. Priming also improved the performance of maize at optimal temperature. Maintenance of tissue water contents, reduction in membrane leakage and increase in antioxidant activities, and carbohydrate metabolism seemed to induce chilling tolerance by CaCl2. Seed priming with 100 mg l−1 CaCl2 was the optimal concentration in improving the performance of hybrid maize both under optimal and stress conditions.  相似文献   

10.
为了探究褪黑素(Mt)对低温环境下菜豆种子的影响,本研究对菜豆种子进行低温处理(LT)和低温加褪黑素的处理(LT+Mt),并设置常温处理作为对照(CK),对同时期的各项生理指标进行测定。结果表明：Mt可以提高低温胁迫下的种子萌发率,但萌发率要低于对照;同时对渗透调节物质、O2-和MDA、抗氧化酶活性进行测定,发现低温增加了渗透调节物质的含量,当加入Mt后其含量进一步增加;低温处理后O2-和MDA的含量增加,当加入Mt后其含量明显降低,但是要高于对照;低温处理后抗氧化酶活性略低于对照,当加入Mt后其含量显著升高。研究表明外源Mt有效的减轻了低温对种子萌发的损害,从而促进种子萌发过程中抵御低温的能力。  相似文献   

11.
M. Havaux 《Plant Breeding》1989,102(4):327-332
Chilling temperatures drastically inhibited the photochemical quenching of chlorophyll fluorescence (qQ) measured in intact leaves photosynthesizing under steady-state conditions. This effect appeared, however, to be characteristic of chilling-susceptible plant species and was not observed in plants which are known to be chilling-tolerant, indicating that the measurement of qQ can serve in practice to estimate rapidly the relative chilling tolerance of crop plants. A large number (28) of sweet sorghum (Sorghum bicolor) and Sudan grass (Sorghum sudanense) genotypes were screened for chilling tolerance using this rapid qQ method. Although sweet sorghum and sudan grass obviously behaved as chilling-sensitive plants, a considerable variation for chilling susceptibility was observed among the different genotypes tested. Some sweet sorghum varieties, such as ‘Dale’ and ‘Keller’, and most of the sudan grass varieties appeared to possess a certain degree of resistance towards low temperature stress, indicating the existence of useful germplasms in Sorghum for improving stress tolerance.  相似文献   

12.
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   

13.
本研究旨在实现水稻低温灾害的实时动态监测,改善目前遥感数据在南方地区应用受云雨天气影响受限的现状。利用CLDAS气温数据,结合遥感水稻种植本底信息,参考低温冷害监测指标,选取广西典型早稻低温冷害过程进行监测试验。试验结果表明：利用CLDAS气温分量数据可对区域气温变化状况进行有效的动态监测,结合水稻种植空间分布信息,可实现精细化的水稻受灾面积及等级监测。CLDAS反演的气温精度较高,与气象台站实测气温误差多小于0.5℃。CLDAS和遥感数据结合可为水稻精细化低温冷害监测提供一种新的有效途径。  相似文献   

14.
The effect of short warm breaks (from 15 min to 5 h) during chilling of three chilling-sensitive species (tomato, maize and soybean) was investigated. Injuries, intensity of net photosynthesis and antioxidant enzyme activity were measured. Throughout chilling treatment, plants were warmed by transferring them during the last few hours of the light phase from chilling temperature (5 °C for tomato and maize, 2 °C for soybean) to 20 °C. After warming, seedlings were moved back to chilling conditions. Warm breaks of 5 h almost entirely prevented the appearance of injuries, as measured by changes in leakage of electrolytes and tissue water content, during 12 days of chilling. Even a 15-min warm break ensured a significant decrease in injuries in chilled maize seedlings compared to continuously chilled seedlings. Inhibition of gas exchange and fluorescence in seedlings of two maize genotypes differing in chilling resistance was, to a small extent, prevented by 1-h warm breaks, while 4-h warm breaks reduced inhibition significantly. The length of the warm break (1 or 4 h) had no influence on changes in SOD activity compared to continuously chilled plants, but warm breaks of 4 h produced a significant increase in CAT activity. The possible influence of an alternative pathway in preventing injuries is discussed.  相似文献   

15.
Coronatine (COR) is a new plant growth regulator that mimics the biological activities of methyl jasmonate. We determined whether COR enhanced chilling tolerance of cucumber ( Cucumis sativus L. cv. Jinchun 4) seedlings and if such tolerance was correlated with changes in the activity of antioxidant enzymes. COR was applied to seedlings at two-leaf stage at 0 (Control), 0.1, 1, 10, and 100 n m . Seedlings were then subjected to chilling stress at 5 ± 1 °C for 4 days. Seedlings treated with COR showed significant higher tolerance to chilling stress and the optimal concentration was 1–10 n m . Compared with control, the chilling injury index (CII) of the seedlings treated with COR at 1 and 10 n m was decreased by 44.9 % and 24.5 %, respectively, while the membrane chilling stability (MCS) expressed as the change of relative conductance was increased by 37.2 % and 17.0 %, respectively. The malondialdehyde (MDA) content in leaves treated with COR at 1 n m was decreased by 39.7 %, and the O2− production rate and H2O2 content reduced by 28.6 % and 8.5 %, respectively. Treatment with COR at 1 n m increased the activities of superoxide dismutase (SOD) in leaves by 34.4 %, catalase (CAT) by 58.7 % and ascorbate peroxidase (APX) by 23.0 % under low temperature. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities were also significantly improved by 28.9 % and 21.3 % following treatment with COR at 1 and 10 n m , respectively. The overall results suggest that COR enhanced chilling tolerance in cucumber seedlings by improving the antioxidative defence system.  相似文献   

16.
C. Seropian  C. Planchon 《Euphytica》1984,33(3):757-767
Summary The responses of six wheat genotypes to water stress were analysed. Soil moisture (H), leaf water potential (w), photosynthesis (PN), stomatal resistance (rs) and transpiration (T) were measured during a water stress. The genotypes investigated differed in their stress avoidance (w-H relationship) and their stress tolerance (PN-w and rs-w relationships). The most important differences observed concern the mechanisms of tolerance at low leaf water potential: two varieties, Haurani 27 and Baalback, can then maintain a high photosynthetic activity. These observations are in agreement with the drought resistance characteristics already known for these genotypes. Possible applications to wheat breeding are considered  相似文献   

17.
Salinity is a major abiotic stress that limits rice production across rice areas as high‐yielding modern rice varieties are generally sensitive to salt stress. The study was conducted to deduce heritability and combining ability estimates of rice for various morphological and physiological traits using a 7 × 7 full‐diallel‐cross analysis at seedling and reproductive stages. The salinity stress treatment was 12 dS m?1 at the seedling stage and 8 dS m?1 at the reproductive stage. Diallel analysis revealed high for salinity tolerance scores and shoot height, moderate for shoot dry weight and root dry weight and low for Na+ and K+ concentrations and K+/Na+ ratio. The low‐to‐moderate narrow‐sense heritability for number of panicles, number of fertile spikelets, grain weight, spikelet fertility and K+/Na+ ratio suggests a large breeding population and delayed selection for tolerance until later generations. Significant maternal effects indicate that selection of the female parent is very important for desired trait development. The results of this study confirmed that salinity tolerance at the seedling and reproductive stages is regulated by a different set of genes that could be pyramided using different donors to enhance the level of tolerance.  相似文献   

18.
外源物质处理对辣椒幼苗抗冷性的影响   总被引：2，自引：1，他引：1  
以辣椒幼苗为试验材料,分别喷施不同浓度亚精胺、壳聚糖、水杨酸、CaCl2、甜菜碱溶液,采用昼温/夜温为10℃/5℃低温胁迫5天后进行相对电导率、冷害指数、可溶性糖含量、脯氨酸含量、丙二醛(MDA)含量等指标的测定和分析,探讨外源物质对低温胁迫下辣椒幼苗的影响及作用效果。结果表明,适宜浓度的外源物质可以显著降低辣椒幼苗低温胁迫后的相对电导率、冷害指数和MDA的积累量,提高可溶性糖、脯氨酸等渗透调节物质的含量,对提高辣椒幼苗抗冷性有积极作用。亚精胺、壳聚糖、水杨酸、CaCl2、甜菜碱提高辣椒幼苗抗冷性的最佳诱导浓度分别为0.5 mmol/L、50 mg/L、2 mmol/L、10 mmol/L、10 mmol/L。  相似文献   

19.
The time course of injuries and electrolyte leakage as well as changes in leaf water content and relative turgidity during chilling at 5°C, 65 or 100 % relative humidity (RH) were determined for seedlings of two maize hybrids differing in chilling tolerance.
In the course of chilling of entire seedlings the statistically significant injuries and increased leakage of electrolytes occurred first, followed by significant water deficit in leaves which was independent of RH and genotype. However, during prolonged chilling high and significant correlation between the level of chilling-induced water stress and the extent of injuries was observed. Thus it has been assumed that the main factor responsible for primary chilling injuries in maize seedlings is the immediate influence of chilling temperatures on the cell membranes, and not the secondary water stress. The level of the water stress and the extent of the dehydration injuries under chilling conditions depended on the chilling sensitivity of the genotype. Differences between the examined genotypes consisted not only in delayed chilling injuries in a chilling tolerant hybrid, but also in significantly lesser effects of these injures on water relations.
However, exposure to low temperature of the aboveground part or of the roots of the seedlings only, caused first the chilling-induced marked water deficit in the leaves and next increased leakage of electrolytes. A direct effect of chilling temperature on the membranes in a situation when only a part of the seedling is being chilled, may be less harmful to the plant as a whole owing to normal functioning of the non-chilled part.  相似文献   

20.
水稻障碍型冷害及灌溉技术研究现状   总被引：12，自引：0，他引：12  
黑龙江省位于寒地,水稻冷害频繁发生。介绍了障碍型冷害发生过程、特点、伤害机理及其水管理技术,以减轻水稻冷害。结果表明：在水稻冷害敏感期即水稻孕穗期遇到低温冷害,应灌17cm以上水层。在水稻前历期灌10cm也起到防护作用。二者结合效果更好。  相似文献   

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