title: Aquaporin plays an important role in mediating chloroplastic CO2concentration under high-N supply in rice (Oryza sativa) plants.
abstract: Our previous studies demonstrated that chloroplastic CO2concentration (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 mM; intermediate N, 2.86 mM; and high N, 7.14 mM) 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 CO2diffusion conductance (total CO2diffusion conductance/leaf-N content, gt/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 gmdecreased 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.
authors.affiliation: Jiangsu Key Lab for Organic Waste Utilization and National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, Nanjing, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Ding
authors.affiliation: Jiangsu Key Lab for Organic Waste Utilization and National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, Nanjing, China.
authors.forename: Limin
authors.initials: L
authors.lastname: Gao
authors.affiliation: Jiangsu Key Lab for Organic Waste Utilization and National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, Nanjing, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.affiliation: Jiangsu Key Lab for Organic Waste Utilization and National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, Nanjing, China.
authors.forename: Min
authors.initials: M
authors.lastname: Wang
authors.affiliation: Jiangsu Key Lab for Organic Waste Utilization and National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, Nanjing, China.
authors.forename: Mian
authors.initials: M
authors.lastname: Gu
authors.affiliation: Jiangsu Key Lab for Organic Waste Utilization and National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, Nanjing, China.
authors.forename: Binbin
authors.initials: B
authors.lastname: Ren
authors.affiliation: Jiangsu Key Lab for Organic Waste Utilization and National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, Nanjing, China.
authors.forename: Guohua
authors.initials: G
authors.lastname: Xu
authors.affiliation: Jiangsu Key Lab for Organic Waste Utilization and National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, Nanjing, China.
authors.forename: Qirong
authors.initials: Q
authors.lastname: Shen
authors.affiliation: Jiangsu Key Lab for Organic Waste Utilization and National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, Nanjing, China.
authors.forename: Shiwei
authors.initials: S
authors.lastname: Guo