外源芦丁预处理对水分胁迫下玉米幼苗的生理效应

以玉米(Zeamays L.)品种'郏单958'为材料.采用营养液水培法,研究了外源芦丁(Rutin)对聚乙二醇(PEG)胁迫下幼苗叶片质膜相对透性、脯氨酸、可溶性糖含量及保护酶活性的影响.结果显示:(1)在15%PEG-6000胁迫下,玉米叶片的MDA含量、质膜相对透性、脯氨酸和可溶性蛋白质含量均显著增加,保护酶SOD、CAT、POD活性显著升高.(2)一定浓度芦丁(>0.40 g/L)预处理可显著抑制水分胁迫下玉米幼苗叶片MDA含量的上升,降低叶片质膜相对透性,并诱导SOD、POD和CAT活性提高.降低脯氨酸和可溶性蛋白质含量.说明外源芦丁能够提高玉米幼苗的抗氧化作用,缓解水分胁迫引起的膜脂过氧化,保护细胞膜免受或减少损伤·达到提高植物抗旱性的目的.     

渗透胁迫对皱果苋叶片渗透调节物质的影响

目的:研究渗透胁迫下皱果苋的渗透调节物质变化,探讨皱果苋的耐旱机理.方法:分别用浓度为5%、10%和20%PEG6000进行渗透胁迫,处 理皱果苋幼苗0、1、3、5和7d,取叶片测定各项生理指标.结果:随着渗 透胁迫时间的延长,皱果苋幼苗叶片中相对含水量(RWC)逐步下降;而脯氨酸和可溶性糖含 量上升;在5d,5%、10%、20%PEG胁迫下的叶片脯氨酸含量分别是对照的3.73、6.27、9.77 倍;而叶中可溶性糖含量分别是对照的2.87、3.68、5.21倍.胁迫3d,20%PEG处理的材料出 现萎焉现象,胁迫5d,10%PEG处理的材料开始萎焉;在5%和10%PEG胁迫下,可溶性蛋白含量 升高,但在20%PEG胁迫下,可溶性蛋白含量先升后降.结论:在适度的渗 透胁迫下,皱果苋叶片中的渗透调节物质使其具有较强的渗透能力,形成皱果苋耐旱性的内在基础.     

钙素和水分亏缺对黄瓜叶片细胞质膜透性的影响

用控制溶液的钙量[加或不加Ca(NO_3)_2]和渗透势(加聚乙二醇6000,202 g/L)的方法,研究了钙素和水分亏缺对黄瓜叶片细胞质膜透性的影响。结果表明:在渗透胁迫下,正常供钙的黄瓜叶片相对含水量(RWC)和膜透性变化较小、MDA增加不显著、SOD活性无明显改变;缺钙植株叶片的RWC随渗透胁迫处理线性下降,膜透性显著增大、MDA含量迅速提高、SOD活性也升高。在正常水分供应下,与供钙植株相比,缺钙植株SOD活性和MDA含量均较高,但RWC和膜透性无差异。在水分胁迫下,缺钙植株MDA和质膜透性与ΔRWC以及MDA与质膜透性之间均呈正相关。这些结果表明在水分胁迫下,缺钙处理叶片保水能力降低,使受害加重;同时,细胞质膜的稳定性降低。膜透性改变可能与在水分胁迫下体内的膜脂过氧化反应密切相关,即缺钙加速了膜脂过氧化反应,从而损害了质膜结构。     

大穗结缕草幼苗耐盐生理机制及耐盐能力研究

以大穗结缕草为实验材料,采用不同质量分数的NaCl处理后,观察盐胁迫对其生长及生理生化指标的影响.结果表明:随着盐胁迫浓度增大,大穗结缕草幼苗株高、鲜重、干重都逐渐下降,而根容量和根冠比却逐渐上升;随盐胁迫浓度的增大,大穗结缕草幼苗叶片细胞质膜透性和MDA含量逐渐增加,脯氨酸含量持续升高;其多数生长和生理指标在≥2.0% NaCl盐胁迫浓度下与对照差异显著,且此时的脯氨酸含量是对照的10倍以上.研究发现,大穗结缕草幼苗地上部分对盐胁迫更敏感、受害更严重;通过体内脯氨酸积累来减轻渗透胁迫是其可能的耐盐生理机制;2.0%盐胁迫可能是大穗结缕草的最高耐盐浓度.     

冠菌素对玉米幼苗耐干旱胁迫的诱导效应

以玉米幼苗为材料,在20%PEG模拟干旱条件下,研究了植物生长物质冠菌素0.001~1.0μmol?L-1处理时叶片水分状况及其脯氨酸、可溶性糖、MDA含量及抗氧化酶活性.实验表明,在干旱胁迫条件下,低浓度(0.01μmol?L-1)的冠菌素处理能显著降低干旱胁迫下叶片水势,并显著提高玉米幼苗叶片相对含水量、可溶性糖和游离脯氨酸的含量;同时能显著提高玉米叶片中POD、CAT和APX的活性(分别比对照高32.1%、13.8%和29.5%),而对SOD和GR的活性无显著影响;此时叶片中MDA的含量显著比对照降低11.6%,能够在一定程度上维持细胞膜的完整性.高浓度冠菌素处理(1.0μmol?L-1)下各指标的变化趋势则相反.结果证明,低浓度冠菌素(0.01μmol?L-1)能增强玉米幼苗耐干旱胁迫的能力.     

钙对烟草叶片热激忍耐和活性氧代谢的影响

热胁迫导致烟草叶片细胞膜系统显著受损,表现为SOD活性降低和MDA含量明显升高,叶片叶绿素含量下降,活性氧增加。10 mmol/L CaCl2溶液处理烟草幼苗后,能有效降低热胁迫下叶片细胞膜透性,维持较高的SOD和CAT等抗氧化酶活性,减缓 O-·2 形成和膜脂过氧化反应。研究结果表明,CaCl2处理提高了烟草叶片膜稳定性和膜保护酶活性,有利于保护细胞膜结构,降低高温对烟草幼苗的伤害。钙离子螯合剂EGTA能在一定程度上降低烟草叶片的抗热性。     

钙对烟草叶片热激忍耐和活性氧代谢的影响

热胁迫导致烟草叶片细胞膜系统显著受损,表现为SOD活性降低和MDA含量明显升高,叶片叶绿素含量下降,活性氧增加。10mmol/LcaCl2溶液处理烟草幼苗后,能有效降低热胁迫下叶片细胞膜透性,维持较高的SOD和CAT等抗氧化酶活性,减缓O2^-形成和膜脂过氧化反应。研究结果表明,CaCl2处理提高了烟草叶片膜稳定性和膜保护酶活性,有利于保护细胞膜结构,降低高温对烟草幼苗的伤害。钙离子螯合剂EGTA能在一定程度上降低烟草叶片的抗热性。     

强风沙流吹袭对樟子松幼苗生长特性及其逆境生理特征的影响

为了解樟子松幼苗对强风沙流不同时间吹袭的生理生态响应,2013年春季在内蒙古科尔沁沙地研究了8级大风下强风沙流(风速18 m·s-1,风沙流强度173 g·cm-1·min-1)吹袭10、20和30 min樟子松幼苗生长特性和一些生理指标的变化。结果表明:随着风吹时间增加,其株高生长速率下降,茎粗和冠幅生长加快,叶色发黄脱落量增加;与非风吹对照(CK)相比,30 min风吹处理的株高增长量下降52.6%,茎粗增长量、冠幅增长量和叶色发黄脱落量分别增加251.9%、256.0%和466.7%;随风吹时间增加,叶片相对含水量(RWC)和超氧化物歧化酶(SOD)活性下降,丙二醛(MDA)含量、膜透性、过氧化物酶(POD)活性、可溶性糖和脯氨酸含量趋于增加;与CK相比,30 min风吹处理的RWC下降4.1%,MDA和膜透性分别增加10.3%和9.3%,SOD活性下降1.9%,POD活性、可溶性糖和脯氨酸含量分别增加55.5%、26.4%和50.0%。结果说明,强风沙流持续吹袭造成樟子松幼苗水分胁迫,使其高生长受抑,部分叶片发黄脱落,叶片膜脂过氧化加剧,细胞膜受损,为适应强风沙流吹袭,樟子松幼苗加快了茎粗和冠幅生长,通过增加POD活性和可溶性糖、脯氨酸含量以减轻细胞膜伤害,维持细胞正常膨压。     

钼在桃树干旱胁迫响应中的作用解析

以毛桃(Amygdalus persica)实生苗为试材, 研究干旱胁迫下, 钼酸铵处理对钼辅因子硫化酶编码基因(LOS5/ABA3)表达量、脱落酸(ABA)含量及抗旱相关生理指标的影响。结果表明, 干旱胁迫下, 喷施不同浓度钼酸铵处理毛桃实生苗叶片, 其含水量及叶绿素和脯氨酸含量显著高于对照, 且以0.04%钼酸铵处理效果最好; 电解质渗漏率显著低于对照。干旱胁迫下, 与对照相比, 喷施0.04%钼酸铵的毛桃实生苗叶片中LOS5/ABA3表达量显著提高; ABA含量、水分利用效率和净光合速率均高于对照, 蒸腾速率低于对照, 且差异显著; 叶片抗氧化酶活性显著升高, MDA含量显著降低; 离体处理的叶片质量损失减缓, 且差异显著。研究表明毛桃实生苗在干旱胁迫下喷施钼酸铵可通过上调钼辅因子硫化酶编码基因的表达水平, 提高叶片中ABA和脯氨酸含量及抗氧化酶活性, 从而缓解干旱胁迫下的细胞膜氧化伤害, 降低叶片失水速率, 减轻干旱胁迫对毛桃实生苗的伤害。     

干旱胁迫对鹿角杜鹃种子萌发和幼苗生理特性的影响

为探明鹿角杜鹃种子萌发和幼苗生长期的耐旱性,以鹿角杜鹃干种子和90d苗龄幼苗为材料,采用聚乙二醇(PEG-6000)模拟不同程度的干旱胁迫,研究干旱胁迫对其种子萌发、早期幼苗生长及幼苗的细胞膜透性、MDA含量、有机渗透调节物质和抗氧化酶活性的影响,并对种子萌发率、早期幼苗生长量与PEG胁迫浓度间进行了回归分析。结果表明:(1)5%~25%PEG胁迫范围内,随着干旱胁迫程度的增加,鹿角杜鹃种子的发芽启动时间推迟,发芽持续时间延长,发芽率、发芽势、发芽指数、活力指数和幼苗生长量显著降低;重度干旱胁迫(25%PEG)下,鹿角杜鹃种子完全未萌发。(2)发芽率、发芽势、发芽指数、活力指数以及幼苗生长量的变化均与干旱胁迫程度呈极显著负相关关系,回归分析求得鹿角杜鹃种子萌发的半致死PEG干旱胁迫浓度为15.68%、半致矮PEG干旱胁迫浓度为15.37%。(3)随着PEG胁迫浓度的增加,鹿角杜鹃幼苗叶片SOD活性呈先升后降的趋势,但各胁迫处理仍显著高于CK(0%PEG);细胞膜透性、MDA、脯氨酸、可溶性糖含量、POD和CAT活性则在中度(15%~20%PEG)和重度胁迫下显著升高,与干旱胁迫程度呈极显著正相关关系。研究表明,干旱胁迫显著抑制了鹿角杜鹃种子萌发和早期幼苗生长,使其细胞膜受到损伤,同时鹿角杜鹃可通过体内渗透调节物质和抗氧化酶活性的增加来适应干旱环境,使得自身受抑制、损伤程度降到最低。     

Adaptive photosynthetic and physiological responses to drought and rewatering in triploid <Emphasis Type="Italic">Populus</Emphasis> populations

Cuttings of Populus cathayana Rehd, originating from three triploid and one diploid populations with the same parents but different gamete origins, were used to examine physiological responses to drought stress and rewatering by exposure to three progressive water regimes. Progressive drought stress significantly decreased the leaf relative water content (RWC), photosynthesis, and chlorophyll fluorescence parameters, and increased the relative electrolyte leakage, malondialdehyde (MDA), free proline (Pro), and antioxidant enzymes, such as superoxide dismutase, peroxidase, and catalase, in the four populations evaluated. However, compared to the diploid population, triploid populations showed lower relative electrolyte leakage and MDA, higher RWC and Pro content, and more efficient photosynthesis and antioxidant systems under the same water regime. Our data indicated that triploid populations possessed more efficient protective mechanisms than that of diploid population with gradually increasing drought stress. Moreover, some triploid genotypes were less tolerant to water stress than that of diploids due to large intrapopulation overlap.     

顽拗性黄皮种子脱水过程中活性氧清除酶活性的变化

以正常性种子花生为对照,研究了顽拗性黄皮种子脱水过程中活性氧清除酶、膜脂过氧化作用以及电解质渗漏率的变化。随着含水量的下降,黄皮胚的电解质渗漏率和膜脂过氧化产物丙二醛(MDA)含量均显著增加;当黄皮胚含水量下降至40％后,SOD活性开始急剧下降,而POD和CAT活性在胚含水量下降过程中呈现出缓慢下降的趋势。花生胚在含水量从45％降至14％的过程中,电解质渗漏率没有明显增加,MDA含量只有少量增加;当含水量降至14％后,电解质渗漏率出现少量增加。花生胚脱水初期,活性氧清除酶活性明显增加,并在整个脱水过程中维持较高的水平。以上结果表明顽拗性种子黄皮的脱水敏感性与活性氧清除酶相对活性变化有关。脱水引起黄皮胚活性氧清除酶活性降低,活性氧清除能力下降,膜脂过氧化作用加强,膜透性增大。黄皮胚的膜系统可能是脱水伤害的靶位之一。     

Exogenous salicylic acid improves salinity tolerance of <Emphasis Type="Italic">Nitraria tangutorum</Emphasis>

In the present study, the physiological responses of Nitraria tangutorum Bobr. seedlings to NaCl stress and the regulatory function of exogenous application of salicylic acid (SA) were investigated. NaCl in low concentration (100 mM) increased while in higher concentrations (200–400 mM) decreased the individual plant dry weights (wt) of seedlings. Decreased relative water content (RWC) and chlorophyll content were observed in the leaves of seedlings subjected to salinity stress (100–400 mM NaCl). Furthermore, NaCl stress significantly increased electrolyte leakage and malondialdehyde (MDA) content. The levels of osmotic adjustment solutes including proline, soluble sugars, and soluble protein were enhanced under NaCl treatments as compared to the control. In contrast, exogenous application of SA (0.5–1.5 mM) to the roots of seedlings showed notable amelioration effects on the inhibition of individual plant dry wt, RWC, and chlorophyll content. The increases in electrolyte leakage and MDA content in the leaves of NaCl-treated seedlings were markedly inhibited by SA application. The SA application further increased the contents of proline, soluble sugars, and soluble protein. The activities of antioxidant enzymes including superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) were up-regulated by NaCl stress and the activities of SOD, POD, and CAT were further enhanced by SA treatments. Application of SA in low concentration (0.5 mM) enhanced while in higher concentrations (1.0 and 1.5 mM) inhibited APX activities in leaves of NaCl-treated seedlings. These results indicate that SA effectively alleviated the adverse effects of NaCl stress on N. tangutorum.     

水分胁迫对龙眼幼苗叶片膜脂过氧化及内源保护体系的影响

对龙眼（ＤｉｍｏｃａｒｐｕｓｌｏｎｇａｎａＬｏｕｒ．）实生幼苗进行人工水分胁迫,检测其抗氧化酶和抗氧化剂的变化,研究了干旱对叶片膜脂过氧化及内源保护体系的影响,结果表明,在水分胁迫下,龙眼叶片ＲＷＣ下降,电解质渗漏上升,ＲＷＣ的下降和电解质渗漏的上升呈极显著负相关;叶片中ＳＯＤ和ＰＯＤ活性及ＭＤＡ含量明显上升,且与电解质渗漏的增加呈极显著正相关;叶片中可溶性蛋白质,ＧＳＨ含量和ＡｓＡ－ＰＯＤ活性显     

Ecophysiological responses of Abies fabri seedlings to drought stress and nitrogen supply

Abies fabri (Mast.) Craib. (A. fabri) is an endemic and dominant species in typical subalpine dark coniferous forests distributed in mountainous regions of Western Sichuan, China. We investigated the ecophysiological responses of A. fabri seedlings to short‐term experimental drought, nitrogen supply and their interaction. Drought stress was created by excluding natural precipitation with automatically controlled plastic roof that covered the seedlings. Nitrogen fertilization was applied weekly by spraying over seedlings ammonium nitrate solution (50 kg N ha^?1 year^?1) during the growing season of 2009. The results showed that drought stress decreased leaf relative water content (RWC), whereas it caused marked increases in root mass ratio (RMR) and root/shoot mass ratio by 6.19 and 10.39%, respectively, as compared with the control. Drought stress increased malondialdehyde (MDA) content, electrolyte leakage, proline content, soluble sugars content and the activities of antioxidant enzymes, whereas nitrogen supply decreased MDA content, but enhanced activities of some antioxidant enzymes [especially peroxidase (POD)]. In the drought stressed plots, nitrogen supply increased RWC and decreased the content of MDA. The combination of drought stress and nitrogen supply also decreased the activities of antioxidant enzymes. These results indicated that the negative effects of drought stress on A. fabri seedlings might be alleviated by nitrogen supply.     

2，4-D丁酯对罂粟（Papaver somniferum L.）保护酶活性及脂质过氧化作用的影响

罂粟（Papaver somniferum L.）花蕾期用不同浓度的2,4-D丁酯对植株进行处理,测定了4d中叶片相对含水量（RWC）、丙二醛（MDA）含量、膜相对透性及保护酶（SOD、POD）活性变化情况。结果表明：在1ml/L、2ml/L、4ml/L浓度处理下对罂粟叶片RWC影响不显著,8ml/L处理下的RWC随处理时间的延长呈显著下降趋势,第4天比第1天下降了48.7%。在各处理下MDA含量和膜相对透性的变化趋势基本一致,1ml/L、2ml/L、4ml/L处理前期下降,后期升高。8ml/L处理对MDA含量和膜相对透性的影响显著的高于其它处理,随处理时间的延长呈先升高后降低的趋势。保护酶在处理条件下随时间延长其活性有明显的变化：POD活性变化波动较大,除8 ml/L外其它处理在第2、第4天有两次上升峰,8 ml/L峰值出现在第2天,之后下降在第4天达最低。SOD活性先降低后升高,都高于对照,所有处理SOD活性在第3d最低,第4天8 ml/L处理的活性显著的高于其它处理。表明了高浓度（8 ml/L）的2,4-D能使膜脂过氧化而产生较大的损伤,其它浓度处理对膜脂过氧化及膜透性影响相对较小,表明8ml/L的2,4-D是灭杀罂粟的最适用量。     

Effect of nitric oxide and putrescine on antioxidative responses under NaCl stress in chickpea plants

Chickpea plants were subjected to salt stress for 48 h with 100 mM NaCl, after 50 days of growth. Other batches of plants were simultaneously treated with 0.2 mM sodium nitroprusside (NO donor) or 0.5 mM putrescine (polyamine) to examine their antioxidant effects. Sodium chloride stress adversely affected the relative water content (RWC), electrolyte leakage and lipid peroxidation in leaves. Sodium nitroprusside and putrescine could completely ameliorate the toxic effects of salt stress on electrolyte leakage and lipid peroxidation and partially on RWC. No significant decline in chlorophyll content under salt stress as well as with other treatments was observed. Sodium chloride stress activated the antioxidant defense system by increasing the activities of peroxidase (POX), catalase (CAT) superoxide dismutase (SOD) and ascorbate peroxidase (APX). However no significant effect was observed on glutathione reductase (GR) and dehydro ascorbate reductase (DHAR) activities. Both putrescine and NO had a positive effect on antioxidant enzymes under salt stress. Putrescine was more effective in scavenging superoxide radical as it increased the SOD activity under salt stress whereas nitric oxide was effective in hydrolyzing H₂O₂ by increasing the activities of CAT, POX and APX under salt stress.     

干旱胁迫下牛心朴子幼苗相对含水量、质膜透性及保护酶活性变化

牛心朴子(Cynanchum komarovii)幼苗用不同浓度PEG-6000(聚乙二醇)模拟干旱处理,测定处理12d和复水24h中根、叶的RWC、质膜相对透性、MDA含量及几种保护酶(SOD、CAT、POD)活性变化情况,结果表明：高浓度胁迫后期,RWC明显下降,MDA含量增大,致使膜脂过氧化引起膜损伤;低、中浓度胁迫下,RWC下降程度低,细胞膜脂过氧化及膜透性影响小,且可能对膜脂过氧化起到一定的防御作用。复水后,低、中度胁迫下,各项指标能迅速恢复到CK水平,而高浓度胁迫下,除叶质膜透性、MDA含量、SOD活性不能恢复外,根、叶的其余指标均能达到CK水平。保护酶系统的作用,在一段时间内,可能是通过它们之间的相互协调而保持一个稳定的平衡态进行的。     

Salicylic acid induces physiological and biochemical changes in three Red bayberry (Myric rubra) genotypes under water stress

Water stress is one of the main environmental stresses that affect plant growth and development. Salicylic acid (SA) induces water stress tolerance in plants. In this study, the effect of exogenous SA on physiological and biochemical process in Red bayberry (Myric rubra) seedlings, of three different genotypes, that were grown under water stress (soil ranging from 20 to 50 % of field capacity) was evaluated. Results showed that water stress severely affected the relative water content (RWC), photosynthesis, stomatal conductance and enzymes activities. Genotypes differed in RWC, Chlorophyll content, gas exchange parameter, antioxidant enzymes activities and proline, and the genotype Biqi had the RWC, photosynthesis, stomatal conductance and enzymes activities greater than the other two genotypes Wangdao and Shenhong. SA treated plants showed, in general, a higher RWC, chlorophyll content, photosynthetic rate, stomatal conductance, superoxide dismutase activity and proline content, and a lower relative electrolyte conductivity, methane dicarboxylic aldehyde content and catalase activity compared to those of untreated seedlings. These results signified the role of SA in diminishing the negative effects of drought on Red bayberry plants and suggest that SA could be used as a potential growth regulator, for improving plant growth under water stress.     

Exogenous Application of Selenium Mitigates Cadmium Toxicity in <Emphasis Type="Italic">Brassica juncea</Emphasis> L. (Czern &amp; Cross) by Up-Regulating Antioxidative System and Secondary Metabolites

The main aim of the present study was to examine the role of selenium (Se) in ameliorating the toxic effect of cadmium (Cd) in mustard (Brassica juncea) plants. The plants exposed to elevated levels of Cd exhibited reduced biomass, pigment content, and relative water content (RWC). However, supplementation of Se restores the negative effect of Cd and increases biomass, pigment content, and RWC. Osmolyte (proline and glycine betaine) and sugar content were increased under Cd stress and further increase was observed with addition of Se. Cd decreased protein content and supplementation of Se increases it to appreciable levels. Cd also increased production of H₂O₂ and lipid peroxidation, electrolyte leakage, and the activities of antioxidant enzymes such as superoxide dismutase, ascorbate peroxidase, and glutathione reductase. Supplementation of Se decreased accumulation of H₂O₂ and lipid peroxidation, increased the activities of antioxidant enzymes to greater levels, and regulates Cd accumulation in roots and shoots. Ascorbic acid (AsA) and flavonoids decreased with elevated concentrations of Cd; however, tocopherol and total phenols were increased with the same concentrations of Cd. Se application maintains AsA and flavonoid content, and further increase in tocopherol and total phenols were observed with Se in the present study. Overall the results confirm that exogenous application of Se mitigates the negative effects of Cd stress in mustard plants through the regulation of osmoprotectants, antioxidant enzymes, and secondary metabolites.