Photorespiration and Its Role in the Regulation of Photosynthesis and Plant Productivity

作     者：V. I. Chikov G. A. Akhtyamova 

作者机构：Kazan Institute of Biochemistry and Biophysics Russion Academy of Sciences Kazan Russia 

出 版 物：《American Journal of Plant Sciences》 (美国植物学期刊（英文）)

年 卷 期：2019年第10卷第12期

页      面：2179-2202页

学科分类：081704[工学-应用化学] 07[理学] 08[工学] 0817[工学-化学工程与技术] 070303[理学-有机化学] 0703[理学-化学] 

主　　题：Assimilate Transport Apoplast Stomata Invertase Chloroplast 

摘      要：The results of long-term studies of photorespiration are summarized and the unsuccessful attempts to increase productivity by suppressing this process are shown. It has been shown that photorespiration and glycolate metabolism are involved in the regulation of the relationship between light processes in chloroplasts and the dark reactions of carbon dioxide assimilation. The studies were conducted on plants in vivo and were associated with the activity of the apoplastic invertase enzyme, affecting assimilate transport. In violation of donor-acceptor relations between photosynthetic and plant-assimilating organs (removal of part of organs-consumers of assimilates or leaves, increase in nitrate nutrition), the kinetics of inclusion of 14C in glycolate was changed. This is due to the strengthening of the role of the transketolase mechanism of its formation. The study of genetically transformed plants, in which either an additional apoplastic invertase gene was introduced, or the existing gene was blocked and did not act, showed a different change in the ratio of 14C-labeled sucrose/hexose and the transpiration response to reduced light. In this connection, the concept of the mechanism of photorespiration interaction with apoplastic invertase and stomatal apparatus of the leaf is proposed when the ratio of light and dark reactions of photosynthesis or assimilate transport is changed. The essence of the concept is that when the ratio of light and dark processes is disturbed, the concentration of organic acids changes first in mesophilic cells (mainly by photorespiration), and then in the extracellular space. It changes the activity of apoplastic invertase, which hydrolyzes sucrose and prevents it from being exported from the leaf. Hydrolysis of sucrose increases the osmoticity of the aquatic environment of the apoplast, which increases with movement to the stomata. The changed osmoticity of the environment around the stomatal guard cells changes the resistance of CO2 diff