《植物生理学报》 2015, 51(12): 2207-2213

水稻叶绿体抗坏血酸过氧化物酶在干旱和高盐胁迫中的作用

方涛, 董艳苹, 李亚楠, 陈德富, 陈喜文^*

南开大学生命科学学院, 天津300071

通信作者：陈喜文；E-mail: xiwenchen@nankai.edu.cn；Tel: 022-23500133

摘　要：

逆境条件下植物积累大量包括过氧化氢(H₂O₂)在内的活性氧。抗坏血酸过氧化物酶(APX)能分解H₂O₂, 被认为在植物逆境胁迫中发挥着重要作用。水稻APX家族有8个成员, 有关叶绿体APX7 (基质型)、APX8 (类囊体型)在逆境中的功能鲜见报道。本研究以从水稻T-DNA插入突变库中筛选出的Osapx7和Osapx8突变体为材料, 在停止浇水和150 mmol•L^-1 NaCl处理14 d后, 与野生型相比, Osapx7和Osapx8的生长均受到抑制, 叶片萎蔫严重, 但难以从直观上辨别出两者之间的区别。干旱条件下, 与野生型相比, 突变体植株叶片内H₂O₂含量升高, 叶片DAB染色加深, 叶绿素含量和相对水含量下降；而在150 mmol•L^-1 NaCl条件下, 突变体与野生型之间这些指标区别不大。除干旱条件下Osapx8的相对含水量低于Osapx7外, 两者的形态与其他生理指标的变化基本相当。这些结果表明, 水稻叶绿体APXs, 特别是APX8在水稻对抗干旱逆境中发挥着重要的作用。

关键词：水稻; 抗坏血酸过氧化物酶; 干旱胁迫; 高盐胁迫

收稿：2015-07-31   修定：2015-11-18

资助：天津市应用基础与前沿技术研究计划重点项目(14JCZDJC34100)和国家自然科学基金(31571760)。

Function of Rice Chloroplastic Ascorbate Peroxidases in Drought and Salt Stress Conditions

FANG Tao, DONG Yan-Ping, LI Ya-Nan, CHEN De-Fu, CHEN Xi-Wen^*

College of Life Sciences, Nankai University, Tianjin 300071, China

Corresponding author: CHEN Xi-Wen; E-mail: xiwenchen@nankai.edu.cn; Tel: 022-23500133

Abstract:

Plants accumulate a substantial amount of reactive oxide species (ROS) including hydrogen peroxide (H₂O₂) under stress conditions. Ascorbate peroxidases (APX), which catalyze the decomposation of H₂O₂, is thought to play important roles in plant stress response. Rice APX family has eight members, there is little information about the function of chloroplast APX7 (stroma APX) and APX8 (thylakoid-bound APX) in stress response. On the basis of rice Osapx7 and Osapx8 mutants screened from a T-DNA insertion mutagenesis library, we treated the genotypes without watering or watering with 150 mmol•L^-1 NaCl for 14 days. Osapx7 and Osapx8 were significantly inhibited their growth and showed a more severe wilting phenotype compared with wild type. However, it is hard to tell the differences between the mutants from the morphological observation. Under drought stress, the leaves of mutant plants accumulated more H₂O₂ with a darker color in DAB staining, decreased the chlorophyll contents and relative water contents; while under 150 mmol•L^-1 NaCl, no significant differences were shown in these indexes between wild type and these mutants. Except that Osapx8 had a lower relative water content than Osapx7 under drought stress, their morphological and physiological index were roughly similar. These data suggested that chloroplast APXs, particularly APX8, play an important role in drought stress in rice.

Key words: rice; chloroplastic ascorbate peroxidases; drought stress; salt stress