盐旱交叉胁迫对柽柳幼苗生长及生理生化特性的影响

以3年生柽柳为材料,采用盆栽实验测定分析不同盐旱交叉胁迫下柽柳的生长状况、光合色素含量、超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性及丙二醛(MDA)含量,以阐明盐旱交叉胁迫对柽柳幼苗生长及生理生化特性的影响。结果显示:(1)盐胁迫对柽柳生长影响大于干旱胁迫,茎叶对盐旱胁迫的敏感性高于根系部分;随着盐胁迫的加剧,柽柳株高、基径以及干物质量均降低。(2)随盐旱胁迫的加剧,柽柳幼苗叶片光合色素含量先升高后降低,主导影响因子由干旱胁迫转为盐胁迫;重度盐胁迫下,叶绿素a、b下降明显。(3)中度干旱胁迫下,SOD和POD活性随盐胁迫的增强先降低后升高;随盐旱胁迫的加剧,SOD和POD活性逐渐减弱。(4)适度的盐旱胁迫能降低幼苗MDA含量,但重度干旱、轻中度盐分胁迫下MDA含量较高。研究发现,柽柳能通过调整自身生长和生理生化特性来提高其对逆境适应能力,表现出较强的抗旱耐盐性;盐旱胁迫下柽柳表现出一定的交叉适应性,适度的干旱胁迫能增强柽柳的耐盐能力。     

盐旱交叉胁迫对灰胡杨(Populus pruinosa)幼苗生长和生理生化特性的影响

以一年生灰胡杨幼苗为试验材料,利用田间控盐控水的方法,进行干旱和盐胁迫试验,通过测定生长和生理生化指标探讨幼苗在盐旱交叉胁迫下的生长发育及适应规律,旨在阐明干旱及盐交叉胁迫下植物抗旱抗盐机理。研究结果表明:在盐、旱及交叉胁迫下,灰胡杨幼苗抗氧化酶活性、MDA和脯氨酸含量与对照存在显著差异(P0.05)。(1)在8、11 g/L和15 g/L盐处理下,灰胡杨幼苗相对高生长、相对枝长和冠幅增量均受到抑制,且差异显著(P0.05),而干旱胁迫和盐旱交互胁迫下差异不显著。(2)在盐胁迫、盐旱交叉胁迫下,随着胁迫程度的加重,抗氧化酶SOD、POD、CAT活性表现出先增加后降低的趋势,三者协调一致;仅干旱胁迫时,抗氧化酶SOD、POD、CAT活性显著增加;(3)在盐、旱及其盐旱交叉胁迫下,脯氨酸含量呈上升趋势,MDA含量则表现出先降低后升高趋势,这与抗氧化酶活性先升高后降低的趋势相对应。因此,抗氧化酶活性对缓解脂膜过氧化的伤害具有一定限度,MDA含量与抗氧化酶活性呈负相关,灰叶胡杨幼苗在盐旱交叉胁迫下表现出一定的耐性。     

盐旱复合胁迫对小麦幼苗生长和水分吸收的影响

为明确盐害、干旱及盐旱复合胁迫对小麦幼苗生长和水分吸收的影响,从而为盐害和干旱胁迫下栽培调控提供理论依据。以2个抗旱性不同的小麦品种(扬麦16和耐旱型洛旱7号)为材料,采用水培试验,以NaCl和PEG模拟盐旱复合胁迫,研究了盐旱复合胁迫下小麦幼苗生长、根系形态、光合特性及水分吸收特性的变化。结果表明,盐、旱及复合胁迫下小麦幼苗的生物量、叶面积、总根长与根系表面积、叶绿素荧光和净光合速率均显著下降,但是复合胁迫处理的降幅却显著低于单一胁迫。盐旱复合胁迫下根系水导速率和根系伤流液强度显著大于单一胁迫,从而提高了小麦幼苗叶片水势和相对含水量。盐胁迫下小麦幼苗Na~+/K~+显著大于复合胁迫,但复合胁迫下ABA含量却显著小于单一的盐害和干旱胁迫。因此,盐旱复合胁迫可以通过增强根系水分吸收及降低根叶中ABA含量以维持较高光合能力,这是盐旱复合胁迫提高小麦适应性的重要原因。洛旱7号和扬麦16对盐及盐旱复合胁迫的响应基本一致,但在干旱胁迫下洛旱7号表现出明显的耐性。     

NaCl与干旱双重胁迫下黑果枸杞幼苗对外源水杨酸的生理响应

干旱、盐分已成为限制植物生长发育的主要因子,在干旱与NaCl双重胁迫下植物的生长发育受到一定影响。为了探究黑果枸杞（Lycium ruthenicum）对盐旱逆境的适应性,该文采用盆栽试验,研究NaCl与干旱胁迫共同作用对其幼苗生长的影响,并观察盐旱逆境下黑果枸杞幼苗对外源水杨酸（SA）的生理响应,探究提高NaCl与干旱胁迫下黑果枸杞幼苗的存活率。结果表明：外源SA(0.1、0.5 mmol·L^-1)处理下,盐旱双重胁迫下黑果枸杞叶内可溶性糖、可溶性蛋白和脯氨酸含量有所增加,而丙二醛（MDA）含量显著降低（P<0.05）,过氧化氢酶（CAT）、过氧化物酶（POD）和超氧化物歧化酶（SOD）活性上升,且0.5 mmol·L^-1 SA处理效果优于0.1 mmol·L^-1 处理。综上结果可知,黑果枸杞对于轻度盐旱胁迫具有一定的适应能力,适宜浓度SA可提高盐旱逆境中黑果枸杞叶内渗透调节物质含量及抗氧化酶活性,该研究为进一步了解盐旱双重胁迫下黑果枸杞幼苗的生长发育提供相关理论依据。     

外源糖浸种缓解盐胁迫下玉米种子萌发

以玉米品种‘垦玉6号’为材料,在150 mmol·L^-1NaCl胁迫条件下,研究葡萄糖(Glc)和蔗糖(Suc)浸种对玉米种子萌发阶段耐盐性的影响.结果表明: 盐胁迫下,0.5 mmol·L^-1 Glc、Suc浸种可促进玉米种子萌发及幼苗早期生长,其中Glc浸种玉米胚芽和胚根长及相应干质量增加到盐处理的1.5、1.3、2.1、1.8倍;Suc浸种玉米分别增加到1.7、1.3、2.7、1.9倍;盐胁迫下Glc、Suc浸种可减少胚芽中硫代巴比妥酸反应物(TBARS)和过氧化氢(H2O2)含量,与盐处理相比分别降低24.9%、20.6%;Glc、Suc浸种可显著提高盐胁迫下玉米胚芽超氧化物歧化酶(SOD)、抗坏血酸过氧化物酶(APX)、谷胱甘肽过氧化物酶(GPX)、谷胱甘肽还原酶(GR)的活性,并诱导葡萄糖6 磷酸脱氢酶(G6PDH)活性的升高,其中Glc浸种玉米SOD、APX、GPX、GR、G6PDH活性较盐处理分别提高66.2%、62.9%、32.0%、38.5%、50.5%,Suc浸种玉米较盐处理分别提高67.5%、59.8%、30.0%、38.5%、50.4%;Glc、Suc浸种胚芽中抗坏血酸 (ASA)、谷胱甘肽(GSH)含量及ASA/DHA、GSH/GSSG显著提高,其中G6PDH活性与外源糖诱导的较强的抗氧化能力密切相关.Glc、Suc浸种还可提高盐胁迫下玉米胚芽中K⁺/Na⁺,分别为盐处理的2.3、2.4倍.外源 Glc、Suc浸种可通过提高玉米种子抗氧化能力及维持体内K⁺和Na⁺离子平衡缓解盐胁迫对玉米种子萌发的抑制效应.     

盐和重金属复合胁迫对翅碱蓬萌发与生长的影响及调控措施

为探究Zn、Cu与盐复合胁迫对翅碱蓬(Suaeda salsa)萌发生长的影响机理及其调控措施,以翅碱蓬为研究对象,采用水培试验方法,测定Zn、Cu和盐复合胁迫条件下翅碱蓬种子发芽率、萌发速率和幼苗渗透调节物质含量等指标,分析1.5 mg/L吲哚乙酸(IAA)、100 mg/L赤霉素(GA)和0.3%硝酸钾(KNO₃)处理对Zn、Cu与盐复合胁迫条件下翅碱蓬萌发与生长的影响。结果表明：(1) Zn、Cu与高盐复合胁迫极显著降低翅碱蓬种子的发芽率,中高浓度的Zn、Cu与盐复合胁迫极显著降低翅碱蓬种子的萌发速率,Zn、Cu和盐复合胁迫对翅碱蓬种子的萌发生长影响表现为低促高抑效应,影响因子间存在明显的协同效应;(2)Zn、Cu和盐复合胁迫条件下,随着盐浓度的升高,翅碱蓬幼苗体内过氧化氢酶(CAT)、过氧化物酶(POD)和超氧化物歧化酶(SOD)3种抗氧化酶活性呈先升高后降低的变化趋势,Zn、Cu和高盐复合胁迫使翅碱蓬幼苗体内丙二醛(MDA)含量增加近2.5倍;(3)1.5 mg/L IAA溶液浸种12 h可显著提高Zn、Cu与高盐复合胁迫条件下翅碱蓬种子的发芽率和萌发速...     

高温干旱复合胁迫对构树幼苗抗氧化酶活性和活性氧代谢的影响

近年来,全球气温不断升高,亚热带部分地区夏季高温和临时性干旱现象日益显著,高温与干旱严重威胁着植物的生存与生长。采用盆栽和人工气候室方式模拟不同的温度和土壤水分梯度,研究了高温与干旱复合胁迫对构树幼苗超氧化物歧化酶(SOD)、过氧化物酶(POD)与过氧化氢酶(CAT)活性、活性氧代谢和丙二醛(MDA)含量的影响。结果表明:(1)高温或干旱单一胁迫下,构树幼苗SOD、POD、CAT活性增加,复合胁迫下,SOD和POD酶活性高于单一胁迫,且随着复合胁迫时间延长而升高。SOD活性受温度和土壤水分双因素影响极其显著,复合胁迫对SOD活性有一定程度的叠加效应;(2)复合胁迫下,活性氧代谢物与MDA含量均显著高于单一胁迫,表明复合胁迫加剧对植物的伤害。通过改变抗氧化酶活性以减轻膜脂过氧化的伤害作用是有限的。     

镉胁迫对矮牵牛种子萌发、幼苗生长及抗氧化酶活性的影响

采用营养液培养的方法研究了不同浓度镉Cd（0、1、2和4 mmol·L^-1）处理对矮牵牛（Petunia hybrida）种子萌发、幼苗生长及生理特性的影响。结果发现：与对照相比,较低浓度（1 mmol·L^-1）Cd处理下矮牵牛种子萌发和幼苗生长均显著被抑制,当Cd浓度增至4 mmol·L^-1时完全抑制了矮牵牛种子的萌发。Cd胁迫在低浓度时激活矮牵牛幼苗叶片过氧化物酶（POD）、过氧化氢酶（CAT）活性,而高浓度产生抑制效应;抗坏血酸过氧化物酶（APX）和超氧化物歧化酶（SOD）活性与对照相比均显著升高,丙二醛（MDA）含量无显著变化。不同浓度的乙二胺四乙酸(EDTA)的加入使4 mmol·L^-1 Cd胁迫下矮牵牛幼苗叶片POD和APX活性增加,但不影响SOD和CAT活性;此外,6 mmol·L^-1 EDTA使Cd胁迫下矮牵牛幼苗叶片中MDA含量增加。结果表明,Cd胁迫抑制矮牵牛种子萌发和幼苗生长,却使幼苗叶片POD、CAT和APX活性增加,EDTA的加入能够进一步提高Cd胁迫幼苗POD和APX活性。因此,矮牵牛幼苗在Cd胁迫下具有较强的抗氧化损伤的能力。     

外源5-氨基乙酰丙酸对盐胁迫下菘蓝种子萌发及幼苗抗氧化酶活性的影响

采用砂培方式,研究了外源5-氨基乙酰丙酸(ALA)对盐胁迫下菘蓝种子的萌发、幼苗叶片的可溶性糖含量、丙二醛(MDA)含量及其抗氧化酶活性的影响,探讨ALA缓解菘蓝受盐胁迫伤害的响应机制。结果显示:(1)菘蓝种子萌发及幼苗生长在100 mmol·L^-1 NaCl胁迫下受到明显的抑制,种子发芽率、发芽势、发芽指数、活力指数与自然含水量均显著降低,丙二醛含量、可溶性糖含量以及超氧化物歧化酶(SOD)、过氧化物酶(POD)活性显著升高。(2)盐胁迫下适宜浓度的ALA处理显著提高了种子萌发率、自然含水量及SOD、POD和CAT活性,降低了可溶性糖和丙二醛的含量,并以16.7 mg·L^-1 ALA处理盐胁迫下菘蓝种子的发芽率、发芽势最大,其幼苗的SOD、POD、CAT活性最强。研究表明,盐胁迫显著抑制菘蓝种子的萌发及幼苗生长,适宜浓度的ALA能够有效缓解盐胁迫对菘蓝种子萌发及幼苗生长的伤害,提高植株的抗盐性,并以16.7 mg·L^-1 ALA处理效果最佳。     

干旱胁迫对栓皮栎幼苗细根的生长与生理生化指标的影响

为了揭示栓皮栎幼苗对干旱环境的适应能力,采用盆栽实验方法,设置对照、轻度、中度和重度干旱处理,研究了栓皮栎(Quercus variabilis Bl.)幼苗小细根(0.0D≤0.5mm)和大细根(0.5D≤2mm)的生长及生理生化指标对长期持续干旱胁迫的响应。结果显示:胁迫处理120d后,与对照相比,轻度胁迫促进细根数量、长度、表面积、体积和干物质量的增加,而中度和重度胁迫抑制细根生长;干旱胁迫下小细根数量和长度大于大细根,而大细根表面积、体积和干物质量显著大于小细根。干旱导致细根相对含水率、活力下降(P0.001),丙二醛(MDA)含量增加(P0.001);大细根相对含水率和活力高于小细根,但小细根中MDA含量显著高于大细根。与对照相比,轻度胁迫可以积累更多渗透调节物质(脯氨酸、可溶性糖和可溶性蛋白),并保持更高的抗氧化酶活性(超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)和抗坏血酸过氧化物酶(APX));中度胁迫则导致POD和APX活性的降低;而重度胁迫抑制了可溶性蛋白的积累和CAT、POD、APX活性的增加;与大细根相比,小细根渗透调节物质和抗氧化酶活性显著减少。当干旱强度超过中度胁迫时,栓皮栎幼苗细根生长和生理生化适应性降低;小细根对干旱环境的变化更敏感,寿命更短。实验中,即使在重度胁迫下也未发生根系严重脱水和幼苗死亡的现象,表明栓皮栎幼苗有较强的干旱忍受能力,适合在半干旱区植被恢复重建与造林工程中应用。     

Analysis of antioxidant enzyme activity during germination of alfalfa under salt and drought stresses

To understand the adaptability of alfalfa (Medicago sativa L.) to environmental stresses, we analyzed the activity of several antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), and catalase (CAT), in alfalfa shoots and roots subjected to salt and drought stresses during germination. The germination rate of six alfalfa cultivars was comparatively studied under 200 mM NaCl or 35% PEG treatment. Alfalfa Xinmu No. 1 and Northstar varieties were selected as stress-tolerant and -sensitive cultivars, respectively, and were used for further characterization. After NaCl or PEG treatment, Xinmu No. 1 showed enhanced seedling growth, compared with Northstar. Xinmu No. 1 also exhibited low levels of hydrogen peroxide (H₂O₂) production and lipid peroxidation, compared with Northstar. In addition, Xinmu No. 1 showed higher enzymatic activity of SOD, APX, CAT, and POD in its shoots and roots than Northstar. These results seem to indicate that Xinmu No. 1 cultivar's tolerance to salt or drought stresses during germination is associated with enhanced activity of antioxidant enzymes. This study highlights the importance of antioxidant enzymes in the establishment of alfalfa seedlings under drought and salinity conditions typical of desertification.     

Comparative physiological analysis in the tolerance to salinity and drought individual and combination in two cotton genotypes with contrasting salt tolerance

Soil salinity and drought are the two most common and frequently co‐occurring abiotic stresses limiting cotton growth and productivity. However, physiological mechanisms of tolerance to such condition remain elusive. Greenhouse pot experiments were performed to study genotypic differences in response to single drought (4% soil moisture; D) and salinity (200 mM NaCl; S) stress and combined stresses (D + S) using two cotton genotypes Zhongmian 23 (salt‐tolerant) and Zhongmian 41 (salt‐sensitive). Our results showed that drought and salinity stresses, alone or in combination, caused significant reduction in plant growth, chlorophyll content and photosynthesis in the two cotton genotypes, with the largest impact visible under combined stress. Interestingly, Zhongmian 23 was more tolerant than Zhongmian 41 under the three stresses and displayed higher plant dry weight, photosynthesis and antioxidant enzymes activities such as superoxide dismutase (SOD), peroxidase (POD) catalase (CAT) and ascorbate peroxidase (APX) activities compared to control, while those parameters were significantly decreased in salt‐stresses Zhongmian 41 compared to control. Moreover, Na⁺/K⁺‐ATPase activity was more enhanced in Zhongmian 23 than in Zhongmian 41 under salinity stress. However, under single drought stress and D + S stress no significant differences were observed between the two genotypes. No significant differences were detected in Ca²⁺/Mg²⁺‐ATPase activity in Zhongmian 41, while in Zhongmian 23 it was increased under salinity stress. Furthermore, Zhongmian 23 accumulated more soluble sugar, glycine‐betaine and K⁺, but less Na⁺ under the three stresses compared with Zhongmian 41. Obvious changes in leaf and root tips cell ultrastructure was observed in the two cotton genotypes. However, Zhongmian 23 was less affected than Zhongmian 41 especially under salinity stress. These results give a novel insight into the mechanisms of single and combined effects of drought and salinity stresses on cotton genotypes.     

外源甲基乙二醛对干旱胁迫下板栗幼苗的影响

甲基乙二醛(MG)是一种在植物中具有多种功能的新型信号分子.为探究MG对板栗幼苗干旱胁迫的影响,以两年生'黄棚'板栗幼苗为试材,通过聚乙二醇(PEG)模拟干旱胁迫并进行MG及其清除剂N-乙酰半胱氨酸(NAC)处理,分析板栗幼苗叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(...     

高浓度镉、锌及其复合作用对烟草抗氧化系统的影响

采用水培方法,研究高浓度镉(0.1 mmol·L^-1 Cd²⁺)、锌(0.15 mmol·L^-1 Zn²⁺)及其复合作用(0.1 mmol·L^-1 Cd²⁺+0.15 mmol·L^-1Zn²⁺)对烟草种子的萌发率、幼苗叶片活性氧(ROS)水平、抗氧化物浓度、抗氧化酶活性及膜脂过氧化程度的影响.结果表明: 单因子条件下,与对照相比,高浓度镉、锌处理烟草种子萌发率降低;叶片超氧自由基(O₂^-· )产生速率与过氧化氢(H₂O₂)含量升高;过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)、脱氢抗化血酸还原酶(DHAR)、单脱氢抗坏血酸还原酶(MDAR)和谷胱甘肽还原酶(GR)活性升高;谷胱甘肽(GSH)含量及其与氧化型谷胱甘肽比值(GSH/GSSG)下降;丙二醛(MDA)含量升高.与镉、锌单因子处理相比,镉、锌复合处理的烟草种子萌发率显著升高;O₂^-· 产生速率、H₂O₂和MDA含量降低;CAT、APX、MDAR活性在处理末期升高.镉、锌胁迫对烟草可造成生理水平上的损伤,且毒性效应随着处理时间的延长而增强.镉、锌复合作用可缓解镉、锌单因子胁迫对烟草幼苗的毒害.     

Seed Priming with Polyethylene Glycol Induces Physiological Changes in Sorghum (Sorghum bicolor L. Moench) Seedlings under Suboptimal Soil Moisture Environments

Osmopriming with PEG has potential to improve seed germination, seedling emergence, and establishment, especially under stress conditions. This research investigated germination performance, seedling establishment, and effects of osmopriming with PEG on physiology in sorghum seedlings and their association with post-priming stress tolerance under various soil moisture stress conditions. Results showed that seed priming increased the environmental range suitable for sorghum germination and has potential to provide more uniform and synchronous emergence. Physiologically, seed priming strengthened the antioxidant activities of APX, CAT, POD, and SOD, as well as compatible solutes including free amino acid, reducing sugar, proline, soluble sugar, and soluble protein contents. As a result, seed priming reduced lipid peroxidation and stabilized the cell membrane, resulting in increased stress tolerance under drought or excessive soil moisture environments. Overall, results suggested that seed priming with PEG was effective in improving seed germination and seedling establishment of sorghum under adverse soil moisture conditions. Osmopriming effectively strengthened the antioxidant system and increased osmotic adjustment, likely resulting in increased stress tolerance.     

中华蚊母树在干旱-水淹交叉胁迫下形态和活性氧代谢的适应机制

为阐明中华蚊母树(Distylium chinense)在消落带干旱-水淹交叉胁迫下的形态和活性氧(ROS)代谢适应机制,通过控制实验模拟了三峡水库消落带的水文节律,研究了干旱-水淹交叉胁迫及恢复过程施加不同外源物质对中华蚊母树形态学和ROS清除的变化。结果表明：(1)前期干旱胁迫增强了中华蚊母树对后期水淹胁迫的适应,主要表现在叶片脱落、大量不定根的形成及茎基部膨大等形态学的变化;(2)干旱或水淹单一胁迫下,中华蚊母树·OH、■等ROS水平明显高于对照,表现出氧化应激反应,其超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)等抗氧化系统酶活性及脯氨酸(Pro)等抗氧化系统小分子含量也均显著高于对照,表现出一定的抗氧化防御作用机制,且在复合胁迫下,SOD、CAT、APX酶活性及Pro含量显著高于单一胁迫;(3)恢复阶段,相关性分析表明,中华蚊母树清除ROS(·OH、■的酶促(SOD、CAT、APX)及非酶促(Pro)系统具有一定的协同性。同时,恢复阶段施加脱落酸(ABA),内源Pro显著高于正常水平;施加Pro, SOD、CAT等抗氧化酶活性显著高于对照;施加可...     

Melatonin Promotes Rice Seed Germination under Drought Stress by Regulating Antioxidant Capacity

Drought stress is a serious threat to the germination of plant seeds and the growth of seedlings. Melatonin has been proven to play an important role in alleviating plant stress. However, its effect on seed germination under drought conditions is still poorly understood. Therefore, we studied the effects of melatonin on rice seed germination and physiological characteristics under drought stress. Rice seeds were treated with different concentrations of melatonin (i.e., 0, 20, 100, and 500 μM) and drought stress was simulated with 5% polyethylene glycol 6000 (PEG6000). The results showed that 100 μM melatonin can effectively improve the germination potential, rate and index; the vigor index of rice seeds; and the length of the shoot and root. In addition, that treatment also increased the activity of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), and reduced the content of malondialdehyde (MDA). The grey relational grade between the shoot MDA content and the melatonin seed-soaking treatment was the highest, which could be useful for evaluating the effect of melatonin on drought tolerance. Two-way analysis of variance showed that the effect of single melatonin treatment on rice seeds was more significant than that of single drought stress and interaction treatment of drought and melatonin (p < 0.05). The subordinate function results showed that 100 μM melatonin significantly improved the germination and physiological indexes of rice seeds and effectively alleviated the adverse effects of drought stress on rice seedlings. The results helped to improve the understanding of the morphological and physiological involvement of melatonin in promoting seed germination and seedling development under drought stress.     

外源水杨酸对NaCl胁迫下大豆种子萌发和幼苗生长生理的影响

以大豆种子、幼苗为试验材料,采用砂培的方法,研究了0.2mmol·L-1外源水杨酸(SA)对100mmol·L-1 NaCl胁迫下大豆种子萌发、幼苗形态及生物量、膜脂过氧化和抗氧化酶活性的影响。结果显示:NaCl胁迫下,大豆种子萌发和幼苗生长受到显著抑制,且随着胁迫时间的延长(0~3d),大豆幼苗相对电解质渗漏率、硫代巴比妥酸活性产物(TBARS)含量显著升高,超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)活性均明显降低。外源SA促进NaCl胁迫下大豆种子萌发和根茎生长,增加幼苗生物量积累,降低幼苗叶片相对电解质渗漏率和TBARS含量,增强其叶片SOD、CAT、APX活性。研究表明,NaCl胁迫能显著抑制大豆种子萌发和幼苗生长,而一定浓度的外源SA能有效提高NaCl胁迫下大豆种子活力及幼苗抗氧化酶活性,减轻膜脂过氧化程度,缓解NaCl胁迫所造成的伤害,提高大豆幼苗抗盐胁迫的能力。     

种子大小和干旱胁迫对辽东栎幼苗生长和生理特性的影响

在温室内遮阴条件下,设置80%、60%、40%和20%田间持水量(对照、轻度、中度和重度干旱)4个处理,研究种子大小和干旱胁迫对盆栽辽东栎幼苗生长和生理特性的影响。结果表明:大种子(3.05±0.38 g)幼苗的单株叶面积、总干质量和根冠比在所有处理均显著大于小种子(1.46±0.27 g)幼苗,前者的株高、基径、叶片数、比叶面积、相对生长率和净同化率等生长参数在轻度、中度和重度干旱处理均不同程度大于后者。大种子幼苗叶片过氧化物酶(POD)、过氧化氢酶(CAT)和超氧化物歧化酶(SOD)活性均高于小种子幼苗,前者叶片丙二醛(MDA)、可溶性蛋白、游离脯氨酸含量和叶绿素总量在部分干旱处理显著大于后者。除根冠比外,其他生长参数均随干旱胁迫增强逐渐减小,重度干旱处理大、小种子幼苗总干质量分别比对照降低19.4%和20.0%。POD、CAT和SOD活性均随干旱胁迫增强先升后降,在中度干旱处理,大、小种子幼苗POD活性分别显著高于对照126.7%和142.1%,CAT活性分别显著高于对照170.0%和151.9%。在重度干旱处理,大、小种子幼苗MDA含量分别显著高于对照86.5%和68.9%。可...