From the perspective of contribution of exported matter from culm , sheath and leaf to spikelets , leaf brade ranked the first with its exported N element accounting for 21 %  ̄ 33 % of the total accumulated matter .
从茎、鞘、叶三个器官的输出物质对子粒的贡献程度来看,叶片的贡献程度最大,其输出的氮素量占子粒积累总量的21%~33%;