Difference in N uptake capacity between different rice genotypes

Hydroponic experiments were conducted to study nitrogen(N) uptake of eight rice cultivars under three N concentrations(1,2 and 4 mmol/L,respectively).The results showed that there were significant differences on N uptake capacity between different rice cultivars.N accumulation in Nanguang,Yujing 7,Qianyu 421 and Wuyunjing 7 was significantly increased with increasing of N application rate indicating those cultivars had higher responsiveness to N,however,no significant enhancement of N accumulation was observed in Guidan 4,ELIO,Yunjing 38 and 4007 suggesting that those cultivars had lower responsiveness to N.Difference in N uptake responsiveness was linked to their difference in N uptake rate and root characteristics.N uptake rate of high-responding cultivars increased significantly with(increasing) N rate,while their total root length exhibited a comparatively lower variation.Further correlativity analysis between N accumulation in rice and total root length and mean N uptake rate showed that mean N uptake rate was of bigger contribution on rice N acquisition in seeding than total root length.