Influence of Nitrogen Treatment on Yield and Its Relation to Leaf Photosynthesis Characteristics of Japonica Rice Variety Zhejing22 at Late Growing Stage

The aim of this study was to investigate the relationship among the rice yield,rice plant nitrogen use efficiency and leaf SPAD values during different stages,photosynthetic rate and other physiological indexes using the japonica rice variety 'Zhejing22' with the treatments of 4 nitrogen application levels.Results show that net photosynthetic rate(Pn),stomatal conductance(Gs) and transpiration rate(Tr) were raised with the increasing of nitrogen application.The intercellular CO2 concentration(Ci) declined as the increaseing of nitrogen application.Meanwhile,under low and regular nitrogen levels,efficiency of rice plant nitrogen use is high and positive correlations were observed among the rice yield and plant dry matter,nitrogen content,photosynthetic rate.In addition,no remarkable correlation was found under high nitrogen level.