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Aquaporin plays an important role in mediating chloroplastic CO 2 concentration under high‐N supply in rice ( Oryza sativa ) plants
Author(s) -
Ding Lei,
Gao Limin,
Liu Wei,
Wang Min,
Gu Mian,
Ren Binbin,
Xu Guohua,
Shen Qirong,
Guo Shiwei
Publication year - 2016
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/ppl.12387
Subject(s) - oryza sativa , rubisco , aquaporin , photosynthesis , biology , mutant , cultivar , stomatal conductance , apoplast , botany , horticulture , biochemistry , gene , cell wall
Our previous studies demonstrated that chloroplastic CO 2 concentration (Cc) is not sufficient under high‐nitrogen (N) supply in rice plants. In this research, we studied how aquaporins‐ ( AQPs ) mediated Cc under different N‐supply levels. A hydroponic experiment was conducted in a greenhouse with three different N levels (low N, 0.71 m M ; intermediate N, 2.86 m M ; and high N, 7.14 m M ) in a rice cultivar ( Oryza sativa cv. Shanyou 63) and with an ospip1;1 mutant ( Oryza sativa cv. Nipponbare). The photosynthetic nitrogen‐use efficiency ( PNUE ) decreased with increasing leaf‐N content. Under high‐N supply, the estimated Cc was significantly lower than the theoretical Cc and the specific Rubisco activity (carboxylation efficiency/Rubisco content, CE /Rubisco) decreased, because of a decrease of relative CO 2 diffusion conductance (total CO 2 diffusion conductance/leaf‐N content, g t /N) in mesophyll cells. Real Time Quantitative PCR (Q‐RT‐PCR) showed that most OsPIP1s and OsPIP2s expression were downregulated under the high‐N supply. Furthermore, Cc and g m decreased in the ospip1;1 mutant line compared with that of the wild‐type plant. It was concluded that under high‐N supply, the decreased PNUE was associated with non‐sufficient Cc, mediated by AQP in mesophyll conductance.