《植物生理学报》 2015, 51(10): 1749-1756

抗坏血酸-谷胱甘肽循环在紫花苜蓿突变体耐盐性中的作用

马进*, 郑钢, 裴翠明, 张振亚

浙江农林大学风景园林与建筑学院, 浙江临安311300

通信作者：马进；E-mail: majinzjl@163.com；Tel: 13071844269

摘　要：

在不同抗氧化途径中AsA-GSH是最重要的循环系统, 为明确抗坏血酸-谷胱甘肽循环(AsA-GSH)在紫花苜蓿耐盐性中的作用。以紫花苜蓿品种‘Millennium’及其耐盐突变体为材料, 研究其在200 mmol•L-1胁迫下的活性氧代谢及AsA-GSH循环的变化。结果表明, NaCl胁迫下突变体叶片中的过氧化氢(H2O2)含量、超氧阴离子(O2 ¯• )产生速率和丙二醛(MDA)含量、氧化型谷胱甘肽(GSSG)含量、脱氢抗坏血酸(DHA)含量显著低于野生型。突变体叶片中GSH/GSSG和AsA/DHA的比值高于野生型。NaCl盐胁迫下突变体叶片中H2O2与DHA含量呈显著正相关, 与AsA/DHA和GSH/GSSG比值呈负相关。同野生型相比, 突变体叶片中在胁迫期间能够保持较高且相对协调平衡的抗坏血酸过氧化物酶(APX)、脱氢抗坏血酸还原酶(DHAR)、单脱氢抗坏血酸还原酶(MDHAR)和谷胱甘肽还原酶(GR)活性。说明突变体体内AsA-GSH循环能够快速有效地运转, 维持较强抗氧化物质的再生能力, 从而提高抗氧化胁迫能力。该研究结果表明AsA-GSH循环效率是紫花苜蓿耐盐机制的重要生理基础。

关键词：抗坏血酸-谷胱甘肽循环; 紫花苜蓿; 盐胁迫; 突变体

收稿：2015-06-16   修定：2015-09-08

资助：国家自然科学基金(31272494)和浙江省自然科学基金(LY16C170003)。

The Function of Ascorbate-Glutathione Cycle in Salt Tolerance of Alfalfa Mutant

MA Jin^*, ZHENG Gang, PEI Cui-Ming, ZHANG Zhen-Ya

Faculty of Landscape Architecture, Zhejiang Agriculture and Forestry University, Lin’an, Zhejiang 311300, China

Corresponding author: MA Jin; E-mail: majinzjl@163.com; Tel: 13071844269

Abstract:

Among the different antioxidant pathways, the ascorbate-glutathione (AsA-GSH) cycle has been regarded as the most important one in order to the function of AsA-GSH cycle in salt tolerance of alfalfa. In the study, millennium (WT) and a salt tolerant alfalfa mutant (MT) were exposed to 200 mmol•L-1 NaCl to reactive oxygen species (ROS) metabolism and dynamic change of AsA-GSH cycle. The results indicated that H2O2 content, O2 ¯• evolution rate, MDA content, GSSG and DHA contents of the leaves were higher in the wild type than in the mutant; both the ratio of GSH to GSSG and the ratio of AsA to DHA were higher in the mutant than in the wild type. The content of H2O2 was significantly positively correlated to H2O2 and DHA content in the leaves of mutant alfalfa plants under NaCl stress, but negatively correlated to the rate of ASA/DHA and GSH/GSSG ratio. Compared with wild type, mutant could maintain higher activity of APX, DHAR, MDHAR and GR. These concluded that mutant alfalfa had efficient metabolism of ASA-GSH cycle, which scavenged the H2O2 rapidly to alleviate the oxidative damage of NaCl stress. The results showed the efficiency of ASA-GSH cycle are the physiological foundation for alfalfa to withstand salt stress tolerance.

Key words: ascorbate-glutathione cycle; alfalfa; salinity stress; mutant