等渗NaCl和KCl胁迫对高粱幼苗生长和气体交换的影响

本文比较研究了等渗ＮａＣｌ和ＫＣｌ胁迫下,高粱幼苗生长及叶片离子含量、质膜相对透性和有关气体交换参数的变化。结果表明,在低浓度ＮａＣｌ和ＫＣｌ胁迫７天时,高粱生长、含水量和质膜相对透性与对照相比没有明显变化,而净光合速率、蒸腾速率和气孔导度已明显下降,叶肉细胞间隙ＣＯ２浓度明显增加。ＮａＣｌ胁迫下叶片Ｎａ＋含量成倍增加,而Ｋ＋和Ｃａ２＋含量无明显变化。ＫＣｌ胁迫时叶片Ｋ＋含量明显增加,Ｃａ２＋含量明显下降,而Ｎａ＋含量没有明显变化。随着ＮａＣｌ或ＫＣｌ浓度的增加,幼苗生长和叶片含水量明显下降,质膜透性和细胞间隙ＣＯ２浓度明显增加,净光合速率、蒸腾速率和气孔导度进一步下降。ＮａＣｌ胁迫下叶片Ｎａ＋含量进一步增加,Ｋ＋和Ｃａ２＋进一步下降,而ＫＣｌ胁迫下叶片Ｋ＋含量进一步增加,Ｎａ＋和Ｃａ２＋含量进一步下降。ＫＣｌ对高粱生长抑制、质膜透性、Ｃａ２＋含量下降及光合气体交换参数的影响均明显大于等渗的ＮａＣｌ。     

盐碱胁迫下AM真菌对羊草生长及生理代谢的影响

利用盆栽控制试验研究了盐碱胁迫下AM真菌对羊草生长及生理代谢的影响。结果表明,盐碱胁迫显著降低了AM真菌的侵染率与侵染强度,且具有高pH的碱胁迫的抑制效应更强。接种AM真菌一定程度上提高了胁迫下羊草幼苗的生物量及光合色素(Chl a,Chl b和Car)含量。随着盐碱胁迫浓度的增加,羊草幼苗积累了大量的Na~+,并抑制了其对K~+的吸收,接种AM真菌一定程度上降低了Na~+的积累,并缓解了胁迫下K~+含量的降低,提高NO_3~-含量从而改善羊草幼苗的离子平衡。在碱胁迫下,柠檬酸、苹果酸含量均显著提高,在盐胁迫下,仅苹果酸含量显著提高,而接种AM真菌使盐碱胁迫下有机酸含量一定程度降低。在盐碱胁迫条件下,接种AM使羊草体内超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)的活性明显提高,增强宿主植物体内氧自由基的清除能力。接种AM真菌明显提高羊草幼苗抗盐碱能力,因胁迫类型不同,抗逆机理有所差异。研究结果为利用羊草进行生物改良退化盐碱草地以及菌肥的应用提供了科学依据,也为探求羊草-丛枝菌根共生体对盐碱胁迫的响应和反馈提供了数据支持。     

盐分胁迫条件下甜菜碱对小麦幼苗体内Na+、K+和Cl-的含量及其分布的影响

以抗盐品种茶淀红和盐敏感品种中国春等两种小麦为实验材料,研究甜菜碱对盐分胁迫条件下小麦（ＴｒｉｔｉｃｕｍａｅｓｔｉｖｕｍＬ．）幼苗Ｎａ＋、Ｋ＋、Ｃｌ－的吸收、分配的影响。结果表明：外源甜菜碱能够在一定程度上限制幼苗对Ｎａ＋、Ｃｌ－的吸收,阻滞其向地上部分运输的数量和速度,同时提高体内Ｋ＋含量、向上运输效率,降低地上部分对Ｎａ＋、Ｋ＋的选择性（ＳＮａ＋、Ｋ＋）,从而提高小麦幼苗抗盐性和对盐分胁迫的适应性。     

NaCl胁迫对甘薯叶片叶绿体超微结构及一些酶活性的影响

随ＮａＣｌ 胁迫浓度的提高,甘薯叶片叶绿体数目逐渐减少, 类囊体膜片层松散、扭曲、破裂并逐渐解体, 叶绿素含量下降。与此同时,Ｈ２Ｏ２ 、ＭＤＡ 含量增加, ＡＳＰ、ＳＯＤ 活性表现出先上升后下降的趋势。耐盐品种在ＮａＣｌ 胁迫下能维持较强的Ｈ２Ｏ２ 清除能力和较低的ＭＤＡ 水平     

质膜H~＋－ATP酶在玉米叶片渗透调节中的作用

干早胁迫下,玉米幼叶生长部位质膜Ｈ＋－ＡＴＰ酶活性显著上升,游离脯氨酸、可溶性糖和无机离子亦同时在玉米叶片生长部位大量积累,二者之间呈明显的正相关．质膜Ｈ＋－ＡＴＰ酶的专一性抑制剂Ｎａ３ＶＯ４在干旱胁迫下强烈抑制游离脯氨酸的积累,说明ＰＭＨ＋－ＡＴＰａｓｅ参与了玉米叶片的渗透调节过程．     

NaCl胁迫对甘薯叶片叶绿体超微结构及一些酶活性的影响

随ＮａＣｌ胁迫浓度的提高,甘薯叶片叶绿体数目逐渐减少,类囊体膜片层松散、扭曲、破裂及逐渐解体膜片层检叶绿素含量下降。与此同时,Ｈ２Ｏ２、ＭＤＡ含量增加,ＡＳＰ、ＳＯＤ活性表现先上升后下降的趋势。耐盐品种在ＮａＣｌ胁迫下能维持较强的Ｈ２Ｏ２清除能力和较低的ＭＤＡ水平。     

盐胁迫下钙对大麦根系质膜和液泡膜功能的保护效应（简报）

盐胁迫下外加钙可增强大麦根系质膜液泡膜Ｈ＾＋－ＡＴＰａｓｅ、液泡膜质子泵和Ｎａ＾＋／Ｈ＾＋逆向运输活性,促进根系对Ｋ＾＋的选择性吸收和运输,降低叶片的Ｎａ＾＋／Ｋ＾＋比。     

盐胁迫下外源ABA对谷子耐盐愈伤组织生理生化特性的影响

外源ＡＢＡ可使谷子胚性愈伤组织生长减缓,使正常胚性愈伤组织在Ｎａ胁迫下与耐盐生俞伤的生长差异消失,脯氨酸含量在无ＮａＣｌ或１％ＮａＣｌ胁迫下分别提高１４０％和９．３％,而可溶蛋白含量均上降,并有新的ＳＤＳ电泳蛋白南带（９０ｋＤ）出现,过氧化物酶活性及ＳＯＤ活性增高。     

NaCl胁迫下离体小鼠叶片内抗坏血酸与几种生理生化指标变化的…

随着ＮａＣｌ胁迫时间的延长和胁迫强度的增加，离体小麦叶片内抗坏血酸含量逐渐减少。活性氧清除剂处理可缓解由ＮａＣｌ胁迫所引起的抗坏血酸含量下降。ＮａＣｌ胁迫下，叶片内Ｏ＾－２和ＭＤＡ含量增加，叶绿素和类胡萝卜素含量，叶绿体的Ｈｉｌｌ反应活力，叶生光合速率，叶片和线粒体呼吸速率的下降，而外源抗坏血酸对这些过程均有缓解作用。     

NaCl胁迫下抗盐突变体和野生型小麦Na~ 、K~ 累积的差异分析

对抗盐突变体和野生型小麦（ＴｒｉｔｉｃｕｍａｅｓｔｉｖｕｍＬ．）在盐胁迫下Ｎａ＋、Ｋ＋的累积状况进行了比较研究。结果表明,ＮａＣｌ胁迫下突变体根和叶中Ｎａ＋的相对累积较野生型显著地少,同时Ｎａ＋的净累积速率显著地低。这种Ｎａ＋相对累积少的状况在叶中表现尤为明显。两者叶中Ｋ＋含量随盐浓度的增加显著下降,但突变体的含量均高于野生型。突变体根中Ｋ＋的含量也显著高于野生型,且这种差异随盐浓度的提高而增大。分别统计突变体和野生型根和叶中Ｎａ＋的含量以及每株幼苗的Ｎａ＋总量以分析二者Ｎａ＋在根和叶中的分布差异,结果表明３００ｍｍｏｌ／ＬＮａＣｌ胁迫９６ｈ后,突变体根中Ｎａ＋的累积量占其整株幼苗Ｎａ＋累积总量的４４４％,而野生型根中含量占其总量的２４３％。相对于野生型而言,在盐胁迫下突变体根中Ｎａ＋分布比例的提高可有效地减少根中Ｎａ＋向地上部分转运。     

Iodoacetate action on endocytic uptake of different fluid-phase markers by OK renal epithelial cells

When grown in monolayer culture, OK cells display endocytic uptake of soluble fluid-phase markers such as lucifer yellow (LY) and horseradish peroxidase (HRP). The response of this process to metabolic inhibitors was characterized in the present study. Inhibition of cell metabolism by cyanide produced a decrease in cell ATP content which was accompanied by a decrease in uptake of both LY and HRP, confirming the energy-dependence of fluid-phase endocytosis in OK cells. Use of iodoacetate also decreased cell ATP content but its action on endocytosis was unexpected. Cell uptake of HRP was decreased by iodoacetate, similar to the effect of cyanide, but there was a marked increase in LY uptake. Additional studies showed that cyanide did not change intracellular Na+ or intracellular K+ and did not interfere with the Na(+)-dependency of Pi uptake. In contrast, iodoacetate produced a marked increase in Na+, a decrease in K+, and abolished the Na(+)-dependency of Pi transport. The latter was due primarily to a 10-fold increase in Na(+)-independent uptake of Pi. These findings suggest, indirectly, that plasma membrane permeability to Na+, K+, Pi, and small molecules such as LY, may be increased by iodoacetate, possibly through its action as an alkylating agent. This mechanism may allow increased cell uptake of LY through a non-endocytic pathway, and may mask the inhibitory action of iodoacetate on endocytic uptake of LY. These additional effects complicate the use of iodoacetate to interrupt endocytosis.     

外源脯氨酸对镉胁迫下小麦幼苗生长的影响

以高蛋白小麦品种“北农9549”为试材,研究喷施不同浓度脯氨酸(0、1.0、5.0和10.0 mmol·L^-1)对镉胁迫下小麦幼苗生长和重金属吸收的影响.结果表明： 以不施镉为对照,1.0 mmol·L^-1CdCl₂胁迫下,小麦幼苗的根长、株高和干质量分别显著下降24.0%、15.0%和27.5%,叶绿素a、b和类胡萝卜素含量分别显著下降23.3%、6.7%和30.8%,超氧化物歧化酶(SOD)活性降低了18.4%,内源脯氨酸、抗坏血酸和丙二醛(MDA)含量分别显著上升78.6%、31.5%和17.9%,细胞膜相对透性显著升高24.8%,过氧化物酶(POD)活性为对照的2.4倍,并且促进对铜的吸收,抑制锌的吸收.随外源脯氨酸浓度的增加,小麦幼苗的根长、株高、干质量、叶绿素和类胡萝卜素含量均逐渐恢复到对照水平,抗坏血酸、内源游离脯氨酸含量和SOD活性均上升,可溶性蛋白含量先上升后下降,POD活性、MDA含量和细胞膜相对透性下降,而锌积累量升高,镉、铜积累量下降.叶面喷施外源脯氨酸可缓解镉对小麦幼苗生长的胁迫,以喷施5.0～10.0 mmol·L^-1外源脯氨酸效果最佳.     

链格孢菌毒素对紫茎泽兰的致病机理

以叶圆片法分析链格孢菌[Alternaria alternata(Fr.)Keissler]毒素对紫茎泽兰（Eupatorium adenophorum Spreng.)叶组织细胞膜透性、过氧化物酶（POD）、抗坏血酸过氧化物酶（APX）和过氧化氢酶（CAT）活性以及丙二醛（MDA）含量的影响,结果表明,链格孢菌毒素使紫茎泽兰叶组织细胞膜透性上升,Na^ 和K^ 渗漏量增加,膜脂过氧化加强,MDA含量上升;链格孢菌毒素处理的紫茎泽兰叶片中POD、APX和CAT的活性均较对照降低。     

Effect of divalent cations on ion fluxes and leaf photochemistry in salinized barley leaves

Photosynthetic characteristics, leaf ionic content, and net fluxes of Na(+), K(+), and Cl(-) were studied in barley (Hordeum vulgare L) plants grown hydroponically at various Na/Ca ratios. Five weeks of moderate (50 mM) or high (100 mM) NaCl stress caused a significant decline in chlorophyll content, chlorophyll fluorescence characteristics, and stomatal conductance (g(s)) in plant leaves grown at low calcium level. Supplemental Ca(2+) enabled normal photochemical efficiency of PSII (F(v)/F(m) around 0.83), restored chlorophyll content to 80-90% of control, but had a much smaller (50% of control) effect on g(s). In experiments on excised leaves, not only Ca(2+), but also other divalent cations (in particular, Ba(2+) and Mg(2+)), significantly ameliorated the otherwise toxic effect of NaCl on leaf photochemistry, thus attributing potential targets for such amelioration to leaf tissues. To study the underlying ionic mechanisms of this process, the MIFE technique was used to measure the kinetics of net Na(+), K(+), and Cl(-) fluxes from salinized barley leaf mesophyll in response to physiological concentrations of Ca(2+), Ba(2+), Mg(2+), and Zn(2+). Addition of 20 mM Na(+) as NaCl or Na(2)SO(4) to the bath caused significant uptake of Na(+) and efflux of K(+). These effects were reversed by adding 1 mM divalent cations to the bath solution, with the relative efficiency Ba(2+)>Zn(2+)=Ca(2+)>Mg(2+). Effect of divalent cations on Na(+) efflux was transient, while their application caused a prolonged shift towards K(+) uptake. This suggests that, in addition to their known ability to block non-selective cation channels (NSCC) responsible for Na(+) entry, divalent cations also control the activity or gating properties of K(+) transporters at the mesophyll cell plasma membrane, thereby assisting in maintaining the high K/Na ratio required for optimal leaf photosynthesis.     

等渗NaCL和KCL胁迫对高梁幼苗生长和气体交换的影响

本文比较研究了等渗NaCl和KCl胁迫下,高粱幼苗生长及叶片离子含量、质膜相对透性和有关气体交换参数的变化。结果表明,在低浓度NaCl和KCl胁迫7天时,高粱生长、含水量和质膜相对透性与对照相比没有明显变化,而净光合速率、蒸腾速率和气孔导度已明显下降,叶肉细胞间隙CO2浓度明显增加。NaCl胁迫下叶片Na+含量成倍增加,而K+和Ca2+含量无明显变化。KCl胁迫时叶片K+含量明显增加,Ca2+含量明显下降,而Na+含量没有明显变化。随着NaCl或KCl浓度的增加,幼苗生长和叶片含水量明显下降,质膜透性和细胞间隙CO2浓度明显增加,净光合速率、蒸腾速率和气孔导度进一步下降。 NaCl胁迫下叶片Na+含量进一步增加,K+和Ca2+进一步下降,而KCl胁迫下叶片K+含量进一步 增加,Na+和Ca2+含量进一步下降。KCl对高粱生长抑制、质膜透性、Ca2+含量下降及光合气体交换参数的影响均明显大于等渗的NaCl。     

镉处理对油菜生长和抗氧化酶系统的影响

通过盆栽实验研究了Cd处理对油菜生长和抗氧化酶系统的影响.结果表明,油菜整株鲜重、叶鲜重随Cd胁迫呈显著降低趋势.逐步回归表明,叶鲜重下降导致油菜整株鲜重下降.油菜叶细胞膜渗透性和MDA随Cd胁迫增大而增加.Cd处理浓度为20 mg·kg^-1时,叶细胞膜渗透性和MDA分别增加29.68％和15.19％,叶细胞膜渗透性和 MDA呈显著正相关,相关系数为0.823^*.Cd处理浓度为5 mg·kg^-1时,叶绿素a、b和a+b含量达到峰值,分别比对照高23.97%、33.63%和26.45%;Cd胁迫对类胡萝卜素含量无显著影响.几种色素对Cd敏感顺序为：叶绿素b>叶绿素a>叶绿素a+b>类胡萝卜素;3种抗氧化酶对Cd敏感顺序为：POD>CAT>SOD.各生理指标IC50表明,油菜只适宜种植在Cd含量小于5 mg·kg^-1的土壤中.     

两种三叶草萌发期和幼苗期抗性的比较研究

通过测定不同的温度、水分、盐分和光照等条件下,杂三叶和地三叶(考拉)在萌发期和幼苗期的发芽率、发芽势、生长速度、叶绿素含量、组织含水量、脯氨酸含量和细胞膜透性等指标,对两者抗性进行了比较研究。结果表明,在不同盐分浓度处理下,三叶草的叶绿素含量随盐浓度的增加而降低,组织含水量变化不明显,游离脯氨酸含量随盐浓度的增加而增加,细胞膜透性随盐浓度的增加而增强;在不同水分条件处理下,三叶草的游离脯氨酸含量和细胞膜透性随水分的增加而增加,叶绿素含量和组织含水量均变化不明显;在不同光照时间处理下,三叶草的叶绿素含量和游离脯氨酸含量均变化不明显,其细胞膜透性也无较大改变,而组织含水量则随光照时间的增加而增加;在不同温度条件下处理,三叶草的叶绿素含量、组织含水量和游离脯氨酸含量均变化不明显,细胞膜透性随温度的升高而降低。另外,从各项测定结果可以看出,杂三叶的各项性状要强于地三叶。     

臭氧和氟化氢复合熏气对小麦叶片形态和生理机能的影响

用开顶式熏气装置,研究了臭氧（Ｏ＿３）和氟化氢（ＨＦ）单独与复合熏气对春小麦（ＴｒｉｔｉｃｕｍａｅｓｔｉｖｕｍＬ．）叶片伤害症状、叶片的膜透性、糖和叶绿素含量的影响。结果表明,复合熏气比单独熏气对叶片的伤害更重,它们都使膜透性增大,叶绿素含量下降。熏气初期可溶性糖含量升高,伤害加重时则含量下降。研究还得出Ｏ＿３和ＨＦ复合熏气对小麦的伤害具有联合作用,对幼叶的伤害具有协同效应,而对老龄叶的危害似有一定的拮抗作用。     

Salicylic acid induced changes on some physiological parameters symptomatic for oxidative stress and mineral nutrition in maize (Zea mays L.) grown under salinity

It has been proposed that salicylic acid (SA) acts as an endogenous signal molecule responsible for inducing abiotic stress tolerance in plants. The effect of varying salicylic acid (SA) supply (0, 0.1, 0.5 and 1.0mM) on growth, mineral uptake, membrane permeability, lipid peroxidation, H(2)O(2) concentration, UV-absorbing substances, chlorophyll and carotenoid concentrations of NaCl (40 mM) stressed maize (Zea mays L.) was investigated. Exogenously applied SA increased plant growth significantly both in saline and non-saline conditions. As a consequence of salinity stress, lipid peroxidation, measured in terms of malondialdehyde (MDA) content and membrane permeability was decreased by SA. UV-absorbing substances (UVAS) and H(2)O(2) concentration were increased by increasing levels of SA. SA also strongly inhibited Na(+) and Cl(-) accumulation, but stimulated N, Mg, Fe, Mn and Cu concentrations of salt stressed maize plants. These results suggest that SA could be used as a potential growth regulator to improve plant salinity stress resistance.