Study on the nitrogen accumulation and translocation during grain filling in winter barley

Four winter barley cultivars,named Yangsimai 3,Yangsimai 1,Supi 2 and Yangnongpi 2,were used to study N fertilization on nitrogen accumulation and translocation at the stage of grain filling under field condition.The results showed that,the N contents of Yangsimai 3,Yangsimai 1,Supi 2 and Yangnongpi 2 were 2.64%,2.74%,2.63% and 2.45% in green leaves,1.43%,1.83%,1.69% and 1.51% in spikes,and 2.65%,2.63%,2.48% and 2.14% in grains respectively.For Yangsimai 3,Yangsimai 1,Supi 2 and Yangnongpi 2,N accumulation before the stage of flowering(NABF) were 17.68,15.27,19.80 and 14.85 mg/plant and N translocation(NT) were 33.75,25.51,54.24 and 28.83 mg/plant;N accumulation after flowering(NAAF) were 16.06,10.25,6.32 and 5.32 mg/plant and N translocation(NT) were 12.60,10.55,13.48 and 9.54 mg/plant;N translocation efficiency(NTE) were 71.49%,69.84%,68.42% and 64.97%;and N harvest index(NHI) were 84.91%,81.95%,88.47% and 81.90%.NABF,NTA,NAAF and NT increased with increasing N application rate,but NTE and nitrogen transfered to grain(NCR) reduced.Nitrogen accumulation in spikes during grain filling fit Richards equation.The relationship between parameters of the Richards equation and the N accumulation and translocation was studied by path analysis.The results showed that the primary factor affecting nitrogen accumulation and translocation was the maximum accumulation rate and the next was the outset accumulation potential.Higher accumulation rate or less outset accumulation rate was more advantageous for the nitrogen accumulation and translocation.Meanwhile,the nitrogen accumulative amount and the nitrogen accumulative rate during early and middle stages could also affected the nitrogen accumulation and translocation.