γ-氨基丁酸对盐胁迫下番茄活性氧代谢及叶绿素荧光参数的影响

 【目的】探讨外源γ-氨基丁酸(GABA)对提高番茄耐盐性的作用。【方法】采用营养液水培法,以番茄‘金棚1号’为材料,研究外源添加GABA(5 mmol?L-1)对NaCl(50 mmol?L-1)胁迫下番茄幼苗的生长、活性氧代谢、叶绿素含量、净光合速率(Pn)及叶绿素荧光参数的影响。【结果】在正常营养液中添加GABA对番茄幼苗的生长、APX、AsA、H2O2、MDA影响不大,但显著提高了SOD、POD、CAT、GR活性及 的积累;此外,叶绿素含量、Pn、最大光化学效率(Fv/Fm)和非光化学猝灭系数(NPQ)没有发生显著变化,而Chla/b、光合电子传递速率(ETR)、光系统Ⅱ实际量子效率(фPSⅡ)和光化学猝灭系数(qP)明显提高;NaCl胁迫下,外源GABA明显提高了番茄叶片生长速率、SOD、POD、APX、GR的活性以及AsA、GSH含量,减少了 、H2O2和膜脂过氧化产物MDA的积累,但对CAT影响不明显;外源添加GABA处理显著提高了盐胁迫下叶绿素含量、Pn、Fv/Fm、ETR、фPSⅡ和qP,而NPQ显著降低,维持较高的光系统Ⅱ活性。【结论】NaCl胁迫下,外源添加GABA通过促进抗氧化酶活性和抗氧化剂含量的提高,降低H2O2和MDA的积累,保护了细胞膜结构的稳定性,从而减轻盐胁迫对番茄光系统Ⅱ的伤害,增强番茄的耐盐性。

Effects of Exogenous GABA on Reactive Oxygen Species Metabolism and Chlorophyll Fluorescence Parameters in Tomato Under NaCl Stress

【Objective】The objective of this study was to investigate the effects of exogenous γ-aminobutyric acid GABA application on the alleviation of tomato injury of salt stress. 【Method】 Hydroponic experiments were performed to investigate the effects of exogenous GABA application (5 mmol?L-1) on growth, reactive oxygen species metabolism, chlorophyll contents, Pn and chlorophyll fluorescence parameters in seedlings of tomato cultivar ‘Jinpeng No.1’ under NaCl stress (50 mmol?L-1). 【Result】 It was found that exogenous GABA significantly increased activities of SOD, POD, CAT, GR and productive rate of , but slightly affected the growth, APX activity, contents of AsA, H2O2, MDA in tomato leaves under normal nutrient solution. On the other hand, exogenous GABA application to normal nutrient solution had no significant effects on chlorophyll contents, Pn, maximal photochemical efficiency of photosystem II (Fv/Fm) and non-photochemical quenching coefficient (NPQ), but Chl a/b, electron transport rate (ETR), actual photochemical efficiency (ΦPSⅡ) and photochemical quenching coefficient (qP) significant increased in tomato leaves. In comparison to NaCl stress, exogenous GABA application led to a marked increase in leaves growth, activities of SOD, POD, APX and GR, contents of AsA and GSH, as well as decrease in accumulation of , H2O2 and content of final product of membrane lipid peroxidation MDA, but little influence on CAT activity in leaves. Meanwhile, the addition of GABA to the salinized nutrient solution could maintain higher PSⅡ activity through significantly improving chlorophyll content, Pn, Fv/Fm, ETR, ΦPSⅡ and qP, as well as decreasing NPQ. 【Conclusion】Exogenous GABA application enhanced salt tolerance in tomato seedlings and alleviated the salt stress damage to PSII center via enhancing the antioxidant enzymes activities and the contents of antioxidants, reducing the accumulation of H2O2 and protecting the stabilization of membrane from peroxidation.