外源NO对酸枣幼苗抗盐性的影响

Effects of Exogenous NO on Salinity Tolerance of Zizyphus jujuba Seedlings

探讨外施NO减轻NaCl逆境对酸枣植株伤害的生理生态效应,旨在为深入认识NO增强植株的抗逆性及其在酸枣绿色栽培生产上的应用提供科学依据。采用营养液培养方法,设置对照(T1)、0.1mmol/L SNP(T2)、100mmol/L NaCl(T3)、0.1mmol/L SNP+100mmol/L NaCl(T4)4个处理组,研究外施NO对NaCl盐害下酸枣(Zizyphus jujuba Mill)多胺、谷胱甘肽抗氧化酶系统及叶绿素荧光特性的作用。结果表明:100mmol/L NaCl盐害处理抑制了酸枣植株的长势,施加NO明显缓解了NaCl逆境对酸枣植株生长的毒害,外源NO使腐胺(Put)、多胺(PAs)、精胺(Spm)、亚精胺(Spd)含量呈持续上升趋势,提高了叶片还原型谷胱甘肽(GSH)含量、谷胱甘肽还原酶(GR)活性及GSH/GSSG比值,而氧化型谷胱甘肽(GSSG)总量略有下降,谷胱甘肽-S-转移酶(GST)的活性、抗坏血酸(ASA)的总量以及抗坏血酸过氧化物酶(APX)的活性均上升。同时,NO处理亦显著增强了酸枣植株的PSⅡ最大光化学效率(Fv/Fm)、PSⅡ潜在活性(Fv/Fo)、表观光合电子传递速率(ETR)、实际光化学效率(ΦPSⅡ)和光化学荧光猝灭系数(qP),而非光化学荧光猝灭系数(qN)出现下降。施用外源NO通过提高NaCl逆境下幼苗游离态多胺含量,同时增强抗氧化酶活性和非酶抗氧化物质含量,减少光抑制现象,保证摄入光能的合理利用,进而减轻NaCl逆境对酸枣幼苗生长的毒害,提高植株的耐盐性。

This study investigated the physiological and ecological effects of exogenous NO ease Zizyphus jujube seedlings under salinity stress,intended to further understand the NO improved plant resistance and provide theoretical basis for the NO application in green cultivation of Z.jujube.Through nutritional hydroponic cultivation,the effect of exogenous NO on the polyamine,glutathione antioxidant enzymatic system and chlorophyll fluorescence features of Z.jujube seedlings was analyzed under four treatments:control(T1),0.1mmol/L SNP(T2),100mmol/L NaCl(T3),0.1mmol/L SNP+100mmol/L NaCl(T4).Results showed that the100mmol/L NaCl treatment inhibit the growth of Z.jujube seedling,but addition of NO significantly relieved the effect of NaCl stress.Exogenous NO significantly increased the amount of putrescine(Put),polyamines(PAs),spermine(Spm),and spermidine(Spd)under the stressed condition.In addition,NO also increased leaf reduced glutathione(GSH)content,glutathione reductase(GR)activity and GSH/GSSG ratio,but slightly decreased the oxidized glutathione(GSSG)content.Meanwhile,the glutathione-S-transferase activity,the ascorbic acid(ASA)content,and the ascorbic acid peroxidase(APX)activity was increased.At the same time,NO treatment significantly improved the leaf PSⅡmaximum photochemical efficiency(F v/F m),PSⅡpotential active competency(F v/F o),apparent photosynthetic electron transport rate(ETR),actual photochemical efficiency(ΦPSⅡ),and photochemical fluorescence quenching coefficient(qP),but decreased the photochemical fluorescence quenching coefficient(qN).Through increment of polyamine content,activity of antioxidant enzymes and the content of non-enzymatic antioxidants,and reduction of photo inhibition and insurance of rational use of light energy,the application of exogenous NO relieves the NaCl stress on inhibition of growth and improves the salt resistance of Z.jujube seedlings.