摘要
以水稻品种献改优为材料分析了大田及人工光抑制条件下水稻叶片光抑制表现及谷胱甘肽-抗坏血酸循环系统(以下称谷-抗系统)运转状况。结果显示,在夏季典型晴天,午间水稻叶片光合作用表现出较明显的“午休”现象。阴天,“午休”现象消失。表观量子效率分析表明“午休”现象与叶片光抑制有关。晴天水稻叶片谷-抗系统运转速率随日照强度增加而迅速加快,主要表现为谷胱甘肽总量以及谷胱甘肽还原酶活性的明显增加。而GSH/GSSG、抗坏血酸总量以及脱氢抗坏血酸还原酶、抗坏血酸过氧化物酶活性均相对稳定,表明谷-抗系统的运行速率主要受谷胱甘肽含量及谷胱甘肽还原酶活性限制。无CO_2空气、强光及过氧化氢酶抑制剂处理等试验结果证明谷-抗系统运行对于光合机构清除H_2O_2等有毒物质,减轻损伤具有积极意义。还就水稻叶片的光抑制,谷-抗系统运转活性与水稻生产的可能联系进行了初步讨论。
The glutathione-ascorbate cycle and photoinhibition in rice (Oryza sativa cv. Xiangaiyou)leaves under the field condition or with photoinhibitory treatment were examined. The re- sults shown that in clear day in summer, photosynthetic CO_2 fixation rate in rice leaves was depressed at noon (termed as 'midday depression') and was partially reversed in the afternoon. Apparent quantum re- quirement in rice leaves increased largely at noon in a clear day. indicating 'midday depression'was related to photo-inhibition. Glutathione content in rice leaves was raised from ca 150 nmol·g^(-1)FW in the morn- ing to ca 300 nmol·g^(-1)FW at noon in a clear day. More particularly, a nearly two-fold increase in glutathione reductase activity was detected. Ascorbate content as well as dehydroascorbate reductase and ascorbate peroxidase activities remained relatively constant during the whole day. It was also found within 30 min of photoinhibitory treatment, glutathione content and glutathione reductase activity increased respectively about 40% and 70%, whereas no obvious increase both in ascorbate content and in dehydroascorbate reductase and ascorbate peroxidase activities was monitored. Furthermore, a rapid re- sponses of glutathione-ascorbate cycle, characterized by dramatic increase of glutathione content and glutathione reductase activity, to aminotriazole was observed. It was concluded that glutathione content and glutathione reductase activity are the limiting factors for stimulated glutathione-ascorbate cycle, which is probably important for C_3 plants to alleviate photoinhibition.
出处
《中国水稻科学》
CAS
CSCD
北大核心
1992年第4期177-183,共7页
Chinese Journal of Rice Science
基金
江苏省教委自然科学基金
关键词
光合作用
谷胱甘肽
水稻
维生素C
Glutathioe-ascorbate cycle
Photoinhibition
Photosynthesis
