密度和追肥时期对重穗型冬小麦品种L906群体辐射和光合特性的调控效应

Regulating Effects of Density and Top-dressing Time of Nitrogen on Characteristics of Radiation Transmission and Photosynthesis in Canopy of Massive-spike Winter Wheat Variety L906

密度和追肥时期对重穗型高产冬小麦的群体发展 ,冠层辐射和光合特性有明显的调节效应。随着密度增加 ,开花前的叶面积指数 (L AI)、群体净光合速率 (NCP)、群体叶源量 (CL SC)提高 ,但生育后期衰减较快 ;密度过高导致群体透光率下降 ,消光系数增加 ,单茎受光量降低 ,冠层光环境恶化 ,后期旗叶的羧化效率降低 ;密度过低则导致生育前期漏光损失较多。在采取适宜密度的基础上 ,推迟追肥时期 ,可改善小麦生育后期群体的光环境和光合特性 ,有效地协调重穗型小麦的源库关系 。

Regulating effects of planting density and top-dressing time of nitrogen on characteristics of radiation transmission and photosynthesis in canopy of massive-spike winter wheat variety L906 was studied. The results showed that, as the increment of density, the population leaf area index (LAI) , net canopy photosynthetic rate(NCP) and canopy leaf source capacity (CLSC) increased before anthesis, but decreased quickly during grainfilling. The population with higher density resulted in decrease of light transmission, photosynthetically activeradiation received by per stem and carboxylic efficiency of flag leaf, and increase of light extinction coefficient and deterioration of light condition in canopy. Low density population caused loss of light during earlier stage.And suitable density combined with postponing top-dressing of nitrogen could coordinate the relationship between source and sink, increase grain yield and light utilization efficiency of massive spike wheat.