Effects of High Temperature Stress on Microscopic and Ultrastructural Characteristics of Mesophyll Cells in Flag Leaves of Rice

作     者：ZHANG Gui-lian CHEN Li-yun ZHANG Shun-tang ZHENG Hua LIU Guo-hua ZHANG Gui-lian, CHEN Li-yun, ZHANG Shun-tang, ZHENG Hua, LIU Guo-hua (Rice Research Institute, Hunan Agricultural University, Changsha 410128, China)

作者机构：Rice Research Institute Hunan Agricultural University Changsha 410128 China 

出 版 物：《Rice science》 (水稻科学（英文版）)

年 卷 期：2009年第16卷第1期

页      面：65-71页

学科分类：09[农学] 0901[农学-作物学] 0902[农学-园艺学] 090201[农学-果树学] 

基　　金：supported by the National Natural Science Foundation of China (Grant No. 30500315) the Agricultural Technological Results Transformation Item of Ministry of Agriculture, China (Grant No. 05EFN214300193) the Educational Foundation of Hunan Province, China (Grant No. 07C360) 

主　　题：rice high temperature stress heat tolerance flag leaf microscopic characteristic ultrastructure characteristic mesophyll cell cytology 

摘      要：The microscopic and ultrastructural characteristics of mesophyll cells in flag leaves of two rice lines （a thermosensitive line 4628 and a thermo-resistant line 996） under high temperature stress （37℃ during 8：00-17：00 and 30℃ during 17：00-8：00） were investigated using an optical and a transmission electron microscopy. The membrane permeability and malondialdehyde content increased under the high temperature stress, and the increase of both variables was greater in the line 4628 than in the line 996. Under the high temperature stress, the line 996 showed tightly arranged mesophyll cells in flag leaves, fully developed vascular bundles and some closed stomata, whereas the line 4628 suffered from injury because of undeveloped vascular bundles, loosely arranged mesophyll cells and opened stomata. The mesophyll cells in flag leaves of the line 4628 were severely damaged under the high temperature stress, i.e. the chloroplast envelope became blurred, the grana thylakoid layer was arranged loosely and irregularly, the stroma layer disappeared, many osmiophilic granules appeared within the chloroplast, the outer membrane of mitochondria and the nucleus disintegrated and became blurred, the nucleolus disappeared, and much fibrillar-granular materials appeared within the nucleus. In contrast, the mesophyll cells in flag leaves of the line 996 maintained an intact ultrastructure under the high temperature stress. From these results, it is suggested that the ultrastructural modification of the cell membrane system is the primary plant response to high temperature stress and can be used as an index to evaluate the crop heat tolerance.