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Plant responses to soil drying and the metabolic basis of drought-induced limitations in stomatal opening are still being discussed. In this study, we investigate the roles of root-born chemical and hydraulic signals on stomatal regulation in wheat genotypes as affected by soil drought and vapour pressure deficit. Twelve consecutive pot experiments were carried out in a glasshouse. Two bread wheat cultivars (Gönen and Basribey) were subjected to drought under high and low vapour pressure deficit (VPD) in a growth chamber. Total dry matter, specific leaf area, xylem ABA content, xylem osmotic potential, xylem pH, root water potential (RWP), stomatal conductance, leaf ABA content and photosynthetic activity were determined daily during 6 days after the onset of treatments (DAT). In the first phase of drought stress, soil drying induced an increase in the xylem ABA with a peak 3 DAT while RWP drastically decreased during the same period. Then the osmotic potential of leaves decreased and leaf ABA content increased 4 DAT. A similar peak was observed for stomatal conductance during the early stress phase, and it became stable and significantly higher than in well-watered conditions especially in high vapour deficit conditions (H-VPD). Furthermore, xylem pH and xylem osmotic potential appeared to be mostly associated with atmospheric moisture content than soil water availability. The results are discussed regarding possible drought adaptation of wheat under different atmospheric humidity. 相似文献
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水分胁迫下葡萄糖对小麦幼苗光合作用和相关生理特性的影响 总被引：11，自引：0，他引：11
以15%聚乙二醇(PEG-6000)模拟水分胁迫,以不同浓度外源葡萄糖(Glc)处理小麦幼苗,探讨外源Glc对水分胁迫下小麦幼苗生长发育和光合特性的影响。结果表明,水分胁迫显著降低了小麦叶片水势和光合作用,抑制植株的生长,而水分胁迫下外源Glc处理能明显增加叶片水势和光合色素含量,并使水分胁迫和水分胁迫后复水处理条件下,小麦幼苗叶片的净光合速率(Pn)、气孔导度(Gs)胞间CO2浓度(Ci)和叶片水分利用效率(WUE)显著升高,而使蒸腾速率(Tr)下降。同时,外源Glc处理显著提高了水分胁迫下叶片中可溶性糖和脯氨酸的积累,促进不定根和侧根的生长,植株干重比单一干旱处理提高14.32%~40.39%。由此表明,水分胁迫下外源Glc通过促进小麦根系生长和提高叶组织的渗透调节能力,改善叶片的水分状况,提高了叶片的光合功能,促进小麦幼苗的生长,降低了水分胁迫对小麦幼苗生长的抑制作用。 相似文献
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Until now, the carbohydrate dynamics in leaves of rapeseed under drought have largely been unknown. For this reason, a growth chamber study was conducted to examine whether the accumulation of carbohydrates under drought stress contributes to osmotic adjustment in leaf tissue. Plants of the cultivar Titan were subjected to temporary drought in the vegetative and reproductive stages. A third variant of long‐term drought covered the period from leaf development to flowering. The level of sucrose decreased under moderate water deficit, but accumulated under severe long‐term drought. Concentrations of glucose, fructose and trehalose were significantly enhanced and that of raffinose decreased in all the variants of drought. There was no evidence that any of the carbohydrates analysed in this study or the activities of soluble acid and cell wall invertases contributed to a drought‐induced accumulation of osmolytes. The results of this study indicate that osmotic adjustment in response to drought in leaves of the rapeseed cultivar Titan is only limited. It is virtually impossible that carbohydrates function as osmoprotectants in leaves of this cultivar, rising above that of the frequently detected accumulation of proline in rapeseed under water deficit. 相似文献
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Water Deficit Reduced Fertility of Young Microspores Resulting in a Decline of Viable Mature Pollen and Grain Set in Rice 总被引：1，自引：0，他引：1
Pollen formation in rice ( Oryza sativa L.) is highly vulnerable to environmental stresses such as heat, chilling and drought. In rice plants exposed to drought during male reproductive development, the most obvious damage often observed is a decline in the number of engorged pollen and grain set. This has been well characterized in rice under chilling and to a lesser extent under drought stress. Moreover, detailed literature on the immediate effects of drought on developing young microspores in rice is still limited. Here, we report findings from experiments on rice plants exposed to water deficit for three consecutive days during early stages of anther development. When the osmotic potential of the growing medium was equal to or less than −0.5 MPa, as induced by polyethylene glycol, the leaf water potential was significantly lowered and grain set was reduced. A strong correlation between grain set and viable young microspores (P < 0.001, r2 = 0.8223) indicates that water deficit immediately reduced fertility of rice plants at the time of exposure. This result suggests a new underlying mechanism of water deficit-induced pollen abortion in rice. 相似文献
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为研究持续干旱处理对紫斑牡丹(Paeonia rockii)光合生理特性的影响,本研究。以实生苗为材料进行盆栽控水试验,设置对照(compared,CK)、轻度胁迫(light stress,LD)、中度胁迫(moderate stress,MD)、重度胁迫(Severe stress,SD)4个水分处理,研究随着干旱胁迫的加剧,叶片水分生理以及光合生理参数的变化。结果表明:在CK、LD、MD水分梯度下,紫斑牡丹生长正常,但在SD胁迫下受影响明显,植株叶片变黄且萎蔫;各胁迫阶段叶厚、叶水势下降明显,相对含水量(relative water content,RWC)降低幅度小,差异不明显,饱和水分亏(water saturation deficit,WSD)有在MD胁迫下有所升高;干旱胁迫抑制了光合色素合成,叶绿素a(Chlorophyll a,Chla)、叶绿素b(Chlorophyll b,Chlb)、叶绿素总含量(total chlorophyll content,Chla+b)、类胡萝卜素(Carotenoids,Car)显著依次下降,叶绿素比值(Chlorophyll ratio,Chla/b)则相反;干旱胁迫导致叶片净光合速率(net photosynthetic rate,Pn)、气孔导度(Stomatal conductance,Gs)以及蒸腾速率(transpiration rate,Tr)呈现下降趋势,但胞间二氧化碳浓度(intercellular carbon dioxide concentration,Ci)则表现为上升后下降,其中水分利用效率(water use efficiency,WUE)在逐渐上升。在轻度和中度干旱的紫斑牡丹表现出一定的适应性和耐旱能力,而长期重度干旱则对紫斑牡丹影响较为严重,在重度干旱地区栽植需考虑水分供给。本研究为干旱地区和城市的园林绿化植物的选择提供理论支持。 相似文献
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《棉花学报》2018,30(2):155-163
[Objective] The purpose of this study was to examine potential drought tolerance mechanisms in cotton (Gossypium hirsutum L.). Biochemical (antioxidant, protein and compatible osmolyte) and physiological (photosynthesis) responses to drought stress during the flowering and fruiting stages were examined. [Method] Using two cotton genotypes (A001 and A705) with different drought tolerance, a pot study was conducted in 2016 with treatments consisting of control (well-watered) and water stress. Water stress treatment was designed as withholding water from the pots until stomatal closure followed by limited water supply for 25 days where water-stressed plants received 40% of the optimum quantity of water. Measurements were made on soluble protein, proline and malonaldehyde (MDA) concentrations, peroxidase (POD) activity and photosynthetic characteristics (net photosynthetic rate Pn, transpiration rate E, stomatal conductance Gs) during the period of water stress. [Result] The soluble protein concentration was decreased and POD activity and MDA level were increased in the leaf subtending cotton boll of A001 under water deficit when compared with the control, but no response was observed in A705. Proline level responded to water deficit inconsistently between the two genotypes and across all sampling dates. Water stress significantly decreased Pn, E and Gs in the main stem leaves for both A001 and A705. [Conclusion] The results indicated that POD, soluble protein and MDA are involved in A001 and A705 responses to water deficit, and A705 is more tolerant to soil drought than A001. 相似文献
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干旱胁迫对内蒙古草原多根葱生理生化指标的影响 总被引：4，自引：0，他引：4
为了探明内蒙古草原多根葱抗旱性能,采用盆栽控水法研究干旱胁迫对多根葱植物叶片生理生化指标的影响。结果表明,随着干旱胁迫时间的延长,内蒙古草原3个样地(Ⅰ、Ⅱ、Ⅲ)多根葱叶片相对含水量呈显著下降的趋势,叶绿素含量、SOD、POD、CAT活性均呈先上升后下降的趋势,水分饱和亏、相对电导率、脯氨酸、丙二醛含量呈上升的趋势。多根葱干旱性程度与水分饱和亏、相对电导率、膜脂过氧化作用呈正相关,与叶绿素含量、相对含水量、保护性酶活性呈负相关。隶属函数法抗旱性综合评价耐旱性强弱顺序为ⅠⅢⅡ。 相似文献
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以叶片衰老快慢不同的两个棉花品系L21和L22为材料,研究了NaCl胁迫对棉花叶片衰老的影响及其相应的生理学机制。温室内水培棉苗,待第5片真叶展开20 d后用含125 mmol·L-1 NaCl的营养液处理棉苗,以不含NaCl的营养液处理为对照。结果显示,NaCl胁迫下L21和L22叶片中叶绿素含量和光合作用速率下降,叶片和根中的Na+含量上升、K+含量降低;NaCl胁迫还增加了棉株体内脱落酸（ABA）含量、降低了玉米素核苷（ZR）含量。表明K+含量降低以及ABA含量升高、ZR含量下降是NaCl胁迫促进棉花叶片衰老的重要原因。 相似文献
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The aim of this study was to determine whether the resistance and/or sensitivity to drought stress, can be attributed to the level of phenolic compounds in the leaves of maize genotypes. The experiments were carried out on seedlings of three maize genotypes characterized by different levels of drought resistance. Experiments with three periods of drought were conducted (8, 11 and 14 days), to obtain plants with different levels of water potential in leaves, which induced changes in the total phenolic content and ferulic acid, and l ‐phenylalanine ammonia‐lyase (PAL) activity. Only for the drought‐resistant genotype Tina, was the low water potential found to be correlated with the high level of the total phenolic content and ferulic acid, which is the main source of blue fluorescence emissions. Moreover, only for Tina were the highest intensities of blue fluorescence emission correlated with the low water potential in leaves. The phenolic compounds present in leaf tissues can protect the deeper situated mesophyll, by absorbing light reaching the leaf and transforming it into a blue fluorescence. Phenolic compounds can, in this way, function as photoprotectors limiting the excitation of chlorophyll during conditions of water deficit in leaves. 相似文献
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M. L. Praba J. E. Cairns R. C. Babu & H. R. Lafitte 《Journal of Agronomy and Crop Science》2009,195(1):30-46
Rice is used as a model cereal to study drought response at the molecular level, with the goal of applying results to other cereals. To assess the relevance of results from rice to other species, the kinetics of drought development and plant response of tolerant and susceptible tropical rice ( Oryza sativa L.) and subtropical wheat ( Triticum aestivum L.) cultivars were compared under vegetative and reproductive stage drought in pot experiments. Water was withheld during reproductive stage until plant available soil moisture content was 30 % of field capacity (FC) or leaf wilting was observed, and then reapplied. Rice reached 30 % FC 9 days after withholding water and wheat after 13 days. Before rewatering, both species reached leaf water potentials of −12 bars and similarly low transpiration rates. Stress reduced leaf relative water content, leaf elongation and membrane stability. When water stress was imposed during reproductive stage, pollen fertility was most affected in wheat, while panicle exsertion and anther dehiscence were severely affected in rice. When water stress was imposed during vegetative stage, wheat was less affected to vegetative stage drought than rice. The nature of differences between tolerant and susceptible cultivars was similar for the two species. However, the differential growth habitats and growth rate of plants needs to be considered in these kinds of experiments. 相似文献
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Senescence of wheat leaves is related to the increase of proteolytic activities and to lower photosynthetic performance. A good nitrogen fertilization management generally delays the senescence of the crop photosynthetic tissues; in environments without terminal water-stress this can improve crop yield and grain quality.
The effects of two N levels, 70 and 210 kg/ha and three side-dressing timings (at double ridge, stem elongation and anthesis) on proteolytic activities and carbon exchange rate (CER) in the flag leaf were investigated from anthesis to maturity; the cultivar was Saliente , a high quality, bread-making winter wheat and the site was near Udine, Northern Italy.
With high N level, endoprotease (pH 4.5) and carboxypeptidase (pH 5.5) activities increased up to the last sampling, while with low N these activities dropped earlier. Soluble protein decreased steadily, and its level was influenced by endoproteolytic activities. With high N, total chlorophyll content was degraded later if compared with low N treatment. The latest N side-dressing initially increased leaf chlorophyll and soluble protein contents, but they did not exceed the levels of second side-dressing timing. This was related to an increased auto-proteolytic activity. Leaf carbon exchange rate decreased after anthesis; comparing the two N levels, only at the last measurement the N210 level obtained higher values. 相似文献
The effects of two N levels, 70 and 210 kg/ha and three side-dressing timings (at double ridge, stem elongation and anthesis) on proteolytic activities and carbon exchange rate (CER) in the flag leaf were investigated from anthesis to maturity; the cultivar was Saliente , a high quality, bread-making winter wheat and the site was near Udine, Northern Italy.
With high N level, endoprotease (pH 4.5) and carboxypeptidase (pH 5.5) activities increased up to the last sampling, while with low N these activities dropped earlier. Soluble protein decreased steadily, and its level was influenced by endoproteolytic activities. With high N, total chlorophyll content was degraded later if compared with low N treatment. The latest N side-dressing initially increased leaf chlorophyll and soluble protein contents, but they did not exceed the levels of second side-dressing timing. This was related to an increased auto-proteolytic activity. Leaf carbon exchange rate decreased after anthesis; comparing the two N levels, only at the last measurement the N210 level obtained higher values. 相似文献
13.
以1年生长柄扁桃幼苗为材料,通过盆栽控水试验的方法,设置土壤含水量分别为田间持水量的50%~75%（轻度干旱胁迫）、75%~100%（对照）和100%~125%（水涝胁迫）,研究不同土壤水分胁迫对长柄扁桃幼苗生长特性及蒸散耗水规律的影响。结果表明,水分胁迫对长柄扁桃幼苗生长及蒸散耗水具有明显影响,长柄扁桃蒸散耗水量随水分胁迫程度的加剧呈下降趋势。轻度水分胁迫有利于长柄扁桃株高、基径、叶面积及新枝数的生长,但叶片衰老较快。水涝胁迫在一定程度上有利于长柄扁桃叶面积及基径的生长并能减缓叶片衰老,但不利于株高及新枝数的增加。综合分析认为,轻度水分胁迫是长柄扁桃幼苗生长的适宜土壤水分含量。 相似文献
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水分胁迫对贪青水稻籽粒充实及其淀粉合成关键酶活性的影响 总被引：8，自引：1，他引：8
以两个灌浆速率差异较大的杂交稻组合(汕优63，Pc311/早献党)为材料，设置出穗后高氮(HN)和正常氮(NN)两个水平，以正常灌水为对照(WW)，研究适度水分胁迫(WS)对水稻籽粒灌浆速率与籽粒中淀粉合成关键酶活性的影响。结果表明， HN导致水稻贪青迟熟，主要表现为淀粉积累速率和积累量显著下降，造成粒重和产量降低。适度水分胁迫处理能有效改善贪青稻株的籽粒充实状况。施高氮导致水稻籽粒中蔗糖合成酶(SuSy)、腺苷二磷酸葡萄糖焦磷酸化酶(ADP-Gppase)、颗粒结合淀粉合成酶(GBSS)、可溶性淀粉合成酶(SSS)和淀粉分支酶(SBE)活性降低，是贪青稻株籽粒淀粉积累速率下降和充实不良的内在生理原因。适度水分胁迫处理能诱导籽粒中SuSy、ADP-Gppase、SSS和SBE活性上升，进而增加籽粒淀粉积累和粒重。而正常施氮下，水分胁迫导致稻株籽粒灌浆后期同化物供应不足和淀粉合成代谢酶活性下降过快，是其籽粒淀粉积累总量减少、粒重降低的主要原因。 相似文献
15.
多胺延缓水分胁迫下小麦幼苗衰老机制的探讨 总被引：5，自引：1，他引：5
研究了在土壤自然干旱的水分胁迫条例上，干旱诱导的小麦叶片衰老与小麦叶内源多胺水平之间的关系，结果表明，土壤干旱胁迫促进小麦幼苗衰老，不同处理产内源多胺水平与水分，蛋白质和核酸代谢之间存在一定的相关性，较高的内源多胺水平有利于小麦叶片在水分胁迫过程中保持较好的水分状况，延缓蛋白质和核酸的降解。 相似文献
16.
Stay green trait in grain sorghum: relationship between visual rating and leaf chlorophyll concentration 总被引：8，自引：1，他引：7
Post‐flowering drought tolerance is referred to as the stay green trait in sorghum. Plants with stay green resist drought‐induced premature plant senescence. In breeding programmes, stay green is evaluated under limited irrigation, post‐flowering moisture‐stress field conditions and visually scored at or soon after physiological grain maturity. The objective of this study was to investigate the relationship between the stay green rating and total leaf chlorophyll content. The parents B35 and Tx7000, and their 98 F, recombinant inbred lines were evaluated in replicated field trials under limited (post‐flowering stress) and full‐irrigation (non‐stress) conditions. After scoring the stay green trait of stressed plants, total leaf chlorophyll contents were measured with a chlorophyll meter (SPAD values) and a spectrophotometer method. The SPAD value had a significant linear relationship with total leaf chlorophyll (R2= 0.91) and with visual stay green rating (with R2= 0.82). Relative water content in top leaves of the stay green lines was about 81%, much higher than non‐stay green lines (38%), indicating that the stay green lines kept the stalk transporting system functioning under severe drought conditions, The results indicate that visual stay green ratings were a reliable indicator of leaf senescence an should be useful to sorghum breeders in evaluating progeny when breeding for drought tolerance. 相似文献
17.
外源甜菜碱对干旱胁迫下小麦幼苗叶绿体抗氧化酶及psbA基因表达的调节 总被引：3，自引：0，他引：3
为了探究外源甜菜碱对干旱胁迫下小麦幼苗的生长调节作用,以优质高产、高抗旱的小麦品种矮抗58为材料,四叶期分别用0.1、1.0和10.0 mmol L−1的GB预处理小麦叶片,同时在根部施加30%聚乙二醇(PEG-6000)以模拟干旱环境,研究其对小麦超氧化物歧化酶(SOD),过氧化氢酶(CAT),过氧化物酶(POD),丙二醛(MDA)、超氧阴离子自由基()产生速率、叶绿素含量及相对含水量的影响,并采用Real-time PCR测定叶绿体psbA基因表达水平的变化。结果表明,干旱胁迫明显减少小麦叶片相对含水量和叶绿素含量,降低SOD、CAT及POD活性,提升MDA含量和O2?产生速率,抑制psbA基因表达水平,而外施GB具一定浓度效应,在适当浓度下能明显缓解这些胁迫反应,调控干旱胁迫下小麦叶绿体抗氧化酶活性以清除多余活性氧,减缓相对含水量及叶绿素含量的降低,提升psbA基因的表达水平,从而加快受损D1蛋白的周转并提高小麦的抗干旱胁迫能力。 相似文献
18.
为研究干旱胁迫对无花果的抗旱生理生化机制,评价无花果对干旱胁迫的反应,以‘布兰瑞克’无花果为试验材料,采取保护地控水试验法,将土壤含水量设置为4个水平,分别为常规供水（CK,田间持水量的65%~75%）、轻度干旱（LD,田间持水量的50%~55%）、重度干旱（MD,田间持水量的40%~45%）、极度干旱（ED,田间持水量的30%~35%）,对比不同干旱胁迫对无花果产量及叶片理化特性的影响。结果表明,无花果叶片相对含水量、叶绿素相对含量随胁迫程度的增大而明显降低,均在ED处理下达最小值,分别较CK降低35.81%、44.40%。叶片蛋白、可溶性糖、丙二醛(MDA)含量随着胁迫程度的增大明显增加,均在ED处理达到最大值,较CK分别增加260%、120%、473%;叶片游离脯氨酸(Pro)渗透调节物质含量明显增加;过氧化氢酶(CAT)、超氧化物歧化酶(SOD)、过氧化物酶(POD)等酶的活性随胁迫程度的增大而显著增强,均在ED处理下达到最大且分别高于CK 33%、90%、360%、6.2%;平均单果重在MD处理下出现最大值为62.11 g,较CK增加20%。ED处理下小区产量最大,达13.90 kg,较CK增加41%。综上,干旱胁迫对无花果产量及叶片生理生化指标有明显影响,在一定范围内胁迫程度越强,无花果产量越低;无花果自身能通过调节渗透物质和酶活性对环境条件做出反应。 相似文献
19.
D. Contour-Ansel G. Ilami A. Ouarzane P. Louguet 《Journal of Agronomy and Crop Science》1996,176(1):59-69
The effect of withholding water on the specific activities of pyruvate, orthophosphate dikinase (PPDK EC 2.7.9.1.) and phosphoenol pyruvate carboxylase (PEPC, EC 4.1.1.31) was studied in two cultivars of Sorghum bicolor L. different in their sensitivity to water deficit. The drought sensitive cultivar ICSV 1063 and the more resistant cultivar MIGSOR were subjected to water deficit in controlled conditions. The results showed a decrease in both enzyme specific activities, higher for drought sensitive cultivar ICSV 1063, when leaf water potential (Ψ) was lowered to -2.3 MPa. Following rewatering, enzyme specific activities increased in both cultivars, with the increase being more significant in MIGSOR. Relative water content (RWC) decreased significantly for water-stressed ICSV 1063 cultivar, lower for MIGSOR and returned quickly to that of control plants upon rehydration. Net photosynthesis showed a decrease for water-stressed plants, higher for ICSV 1063. At minimal Ψ, net photosynthesis was completely inhibited, with the stomata being closed After rehydration, MIGSOR showed a better recovery in photosynthesis but never reached the initial values of day 0. Water stress had a striking effect, both on net photosynthesis by regulation of stomatal aperture and on PPDK and PEPC activities, although the enzymes were still active when photosynthesis ceased. Therefore the level of PPDK and PEPC activities may contribute to the limitation of photosynthetic carbon dioxide fixation. 相似文献
20.
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
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