氮肥对夏玉米灌浆期地上部器官生物量分配的影响

于2009-2010连续2年大田条件下研究3个氮肥处理对玉米地上部不同器官生物量分配的影响。结果表明，长期过量施肥条件下夏玉米地上部各器官生物量所占比重施肥处理间差异不显著。灌浆初期不同器官所占生物量比重表现为：下部茎组>下部叶组>中部叶组>下部鞘组>上部叶组>中部茎组>雄穗>苞叶>中部鞘组>上部鞘组>上部茎组>穗轴>花丝>穗柄；而成熟期为：籽粒>下部茎组>穗轴>下部叶组>中部叶组>苞叶>上部叶组>中部茎组>下部鞘组>中部鞘组>上部鞘组>上部茎组>穗柄>雄穗>花丝。整个灌浆期下部茎组生物量比重下降最大，其次为下部叶组。上部叶组、上部茎组、穗轴的生物量比重与籽粒产量呈显著正相关；而下部叶组、下部鞘组、花丝、雄穗则与籽粒产量呈显著负相关。维持灌浆期上部器官功能期、促进穗部性状物质转移，对于过量施肥条件下形成更高玉米产量具有重要意义。

Effects of Nitrogen Fertilization on Distribution of Aboveground Biomass of Summer Maize during the Filling Stage

The distribution of maize biomass among different organs is the material basis of crop morphological plasticity, which is an important mechanism for dry matter accumulation, transformation and adaptation to the environment. To understand the biomass distribution among maize organs during maize filling periods, an experiment with three nitrogen fertilizer rates was conducted in field in 2009-2010.The results showed that during maize filling stage, the order of the biomass ratio of different organs was followed by: bottom stem> bottom leaf> middle leaf> bottom sheath> upper leaf> middle stem> tassel> husk>middle sheath> upper sheath> upper stem> corncob> corn silk> petiole, while at maturity periods, the order was: grain> bottom stem> corncob> bottom leaf> middle leaf> husk> upper leaf> middle stem> bottom sheath> middle sheath > upper sheath > upper stem> petiole> tassel> husk. The biomass ratio of top leaf, top stem, corn cob was positively and significantly correlated with grain yield, and significant negative correlation was established between biomass ratio of bottom leaf, bottom sheath, corn silk, tassel and yield. These results indicated that maintaining the function of upper organs and advancing the transformation of ear were important for improving maize yield.