Influence of heat stress on leaf ultrastructure, photosynthetic performance, and ascorbate peroxidase gene expression of two pear cultivars(Pyrus pyrifolia)

作     者：Dong-feng LIU Dong ZHANG Guo-qin LIU Sayed HUSSAIN Yuan-wen TENG 

作者机构：State Agricultural Ministry Key Laboratory of Horticultural Plant Growth Development and Quality Improvement Department of Horticulture Zhejiang University College of Horticulture Northwest A&F University 

出 版 物：《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 (浙江大学学报（英文版）B辑（生物医学与生物技术）)

年 卷 期：2013年第14卷第12期

页      面：1070-1083页

核心收录：

学科分类：09[农学] 0902[农学-园艺学] 090201[农学-果树学] 

基　　金：supported by the Earmarked Fund for the Modern Agro-industry Technology Research System China 

主　　题：Pear Ultrastructure Ascorbate peroxidase Subcellular localization Synergistic effect 

摘      要：Plants encounter a variety of stresses in natural environments. One-year-old pot-grown trees of pear(Pyrus pyrifolia Nakai cv. Cuiguan and Wonhwang) were exposed to two heat stress regimes. Under constant short-term heat stress, chloroplasts and mitochondria were visibly damaged. Relative chlorophyll content and maximum photochemical efficiency of photosystem II were significantly decreased, which indicated that the leaf photosynthetic capability declined. Under chronic heat stress, mesophyll cell ultrastructure was not obviously damaged, but leaf photosynthetic capability was still restrained. As chronic heat stress was a simulation of the natural environment in summer, further study of the responses under this stress regime was undertaken. Ascorbate peroxidase(APX) activity was increased in ‘Cuiguan , but not in ‘Wonhwang . Inducible expression of PpAPX genes in the cytoplasm, chloroplasts and peroxisomes was consistent with increased APX activity in ‘Cuiguan , whereas only weak induction of PpAPX genes was observed in ‘Wonhwang . The isoenzymes cytosolic APX1(cAPX1) and stromal APX(sAPX) were confirmed to be localized in the cytoplasm and chloroplasts, respectively.