小麦根系扩展深度对旗叶衰老及光合产物分配的影响

作物根系生长与地上部的生长发育密切相关。为了研究高产小麦根系的分布与旗叶衰老及光合产物运转分配的关系通过池栽的方法，在物理性人为控制根系扩展深度的条件下，对小麦旗叶生理状况及光合产物的分配进行了调查。结果表明，随着小麦群体根系在土壤中扩展深度的增加，小麦生育后期旗叶的衰老速度减缓（SOD、POD活性增加，MDA含量降低），旗叶叶绿素降解速度变慢，而光合作用强度增加。不仅如此，根系的扩展深度还对光合产物的运转分配有影响。根系分布较浅时，运输分配到茎鞘等营养器官的干物质比例较大，而根系扩展较深时，则运输分配到穗部等生殖器官的干物质比例较大。

Effect of Vertical Distribution of Root on Senescence of Flag Leaf and Partition of Dry Matter in High Yielding Winter Wheat

There are a close relationship between the growth of root and the growth of crop upper part. To study the relation between the spatial distribution of root and the plant senescences under the controlled condition which limited the root distribution. Some physiological indexes of wheat flag leaf and the distribution of photosynthetic matter were investigated during the growth of wheat. The result showed that with increasing of the root distribution depth, the senescence speed of flag leaf was getting slower and slower (activity of SOD and POD increasing , content of MDA decreasing), the declining speed of chlorophyll in flag leaf became slow, and Photosyntheis increased . When root system was in shallow layer of the soil, the ratio of dry matter which was transported to vegetative organ such as stem and sheet was relatively high. With the root system expansion to the deep, the partition of dry matter to the grain was becoming more and more.