New Insights into the Nitrogen Form Effect on Photosynthesis and Photorespiration

作     者：GUO Shi-Wei ZHOU Yi GAO Ying-Xu LI Yong SHEN Qi-Rong GUO Shi-Wei ZHOU Yi GAO Ying-Xu LI Yong SHEN Qi-Rong~(*2) College of Resources and Environmental Sciences,Nanjing Agricultural University,Nanjing 210095 (China).

作者机构：College of Resources and Environmental Sciences Nanjing Agricultural University Nanjing 210095 （China） 

出 版 物：《Pedosphere》 (土壤圈（英文版）)

年 卷 期：2007年第17卷第5期

页      面：601-610页

核心收录：

学科分类：09[农学] 0903[农学-农业资源与环境] 090302[农学-植物营养学] 

基　　金：Project supported by the National Basic Research Program of China (No.2005CB121101) National Natural Science Foundation of China (Nos.30400279 and 30671233) International Foundation for Science (IFS)(No.C/3799-1) 

主　　题：ammonium nitrate nitrogen form photorespiration photosynthesis 

摘      要：Under high light conditions, ammonium nutrition has a negative effect on plant growth. This suggests that the adverse effects of ammonium nutrition on plant growth may be related to carbon gain, photosynthesis, and photorespiration. However, there is no consistent evidence of a specific mechanism that could explain the plant growth reduction under ammonium supply. It is generally accepted that during the light reaction, a surplus of nicotinamide adenine dinucleotide hydrogen phosphate （NADPH） is produced, which is not completely used during the assimilation of CO2, Nitrate reduc- tion in the leaf represents an additional sink for NADPH that is not available to ammonium-grown plants. Nitrate and ammonium nutrition may use different pathways for NADPH consumption, which leads to differences in photosynthesis and photorespiration. The morphological （i.e., cell size, mesophyll thickness, and chloroplast volume） and enzymic （i.e., ribulose-1,5-bisphosphate carboxylase/oxygenase （Rubisco）, phosphoenolpyruvate carboxylase （PEPCase）, and glutamine synthetase/glutamate synthetase （GS/GOGAT）） differences that develop when plants are treated with either nitrate or ammonium nitrogen forms are related to photosynthesis and photorespiration. The differences in photorespiration rate for plants treated with nitrate or ammonium are related to the conversion of citrate to 2-oxoglutarate （2-OG） and photorespiratory CO2 refixation.