Effects of Various Nitrogen Fertilizer Treatments on Filling and Respiratory Rate of Rice Caryopsis

Two rice varieties were used as experimental materials to study the effects of N application amount and application time on filling and respiratory rate of rice caryopsis.With N application,the rice caryopsis could maintain higher water content,respiratory rate and dehydrogenase activity in late filling phase,and the course for filling and maintaining higher respiratory rate and dehydrogenase activity of rice caryopsis were prolonged in comparison with no N fertilizer application.More N application at booting was more effective compared to more N application at tillering.