查看文章

Improving physiological N-use efficiency (PE) in rice must be based on an understanding of rice responses to nitrogen management. Field experiments were conducted to investigate the effects of nitrogen management on PE in relation to accumulation and redistribution of dry matter and nitrogen in three rice cultivars, Baguixiang, Liangyoupeijiu and Jinyou 253. The rice plants were grown in spring and summer seasons in 2002 with three N rates of 0, 99 and 157kgha⁻¹ and two panicle nitrogen fractions (PNF) of 1/3 and 2/3. Grain yield, dry weights and nitrogen contents of plants were measured at heading and maturity, respectively. Grain yield exhibited highly significant differences among cultivars and among N rates, but no significant difference between two PNFs. Increasing N rates increased pre- and post-heading and total dry matter accumulation in cultivars except Baguixiang at N rate of 157kgha⁻¹ in the …