百农矮抗58生育后期冠层结构动态变化及产量分析

Effects of Planting Density on Canopy Structure and Yield of BN Aikang 58 at Later Growing Stage

以小麦品种百农矮抗58为材料，通过对其生育后期冠层叶片叶绿素含量、单株叶面积以及透光率进行研究，探讨高产小麦品种冠层结构动态变化特征。结果表明，百农矮抗58群体的自动调节能力强，播量弹性较大，基本苗在135万～270万苗／hm^2条件下其对产量及产量构成因素影响不大；百农矮抗58冠层叶片叶绿素含量、单株绿叶面积和冠层透光率的变化动态呈现一定规律性，花后20d是冠层各测定指标变化的转折点，此时上部叶片叶绿素含量达最大值，而下部叶片急剧衰亡、绿叶面积消失、透光率逐渐增大。冠层上部叶片功能期长，始终是光合主体，为后期籽粒灌浆提供物质基础。

In order to study the canopy structure and its dynamic characteristics of high-yielding wheat variety,the chlorophyll content,leaf area per plant and transmission rate of BN Aikang 58 were measured. The results showed that the planting density had no effects on grain yield and its components at 135×104 --270× 104/ha basic seedlings because BN Aikang 58 had big flexibility of seeding quantity and good self-regulation of population. The dynamic change of chlorophyll content,leaf area per plant and canopy transmittance showed some regularity, the turning point being at 20 d after flowering. At this time, the chlorophyll content of upper leaves reached the maximum value, the transmittance increased gradually in mid-lower part, while the green leaves went away and the transmittance at upper part declined gradually. The upper part of canopy main- tained longer green leaf duration, so it was the photosynthetic body and provided material basis for grain filling at later growing stage.