杂交水稻开花结实期间叶片衰老

在杂交水稻开花期间，通过剪去穗部部分枝梗和叶片等处理，形成不同的库源比，叶片衰老的生理生化指标变化和结实率的测定表明，杂交水稻组合的库源矛盾大，叶片衰老快；但谷粒数与旗叶面积比不一定高，降低库源比，能明显减缓杂交水稻叶片中蛋白质、叶绿素含量及倒3、4、5片叶叶绿素含量的平均值与旗叶叶绿素含量的比率的下降和丙二醇含量的升高。这些都说明杂交水稻叶片功能早衰与其库源矛盾较大有关。

Studies on Leaf Senescence of Hybrid Rice at Flowering and Grain Formation Stage

After sink/source ratio was altered by clipping part of spike and/orleaves of hybrid rice combination atflowering stage, some physiological andbiochemical indices and seed setting Percentage were determined. The resultsindicate that: in comparison with conventional rice, hybrid rice has a largergap between the demand of the sink andthe supply by the source and faster rateof leaf senescence(Figs. 1, 4 ). However, the ratio between the number ofgrains and flag leaf area is not alwayshigher in hybrid rice (Table 2). Reducing sink/source ratio significantly delayed hybrid rice senescence as indicatedby higher chlorophyll and protein levels(Fig. 2 ) and lower malondialdehyde(MDA ) content in leaf (Fig. 5 ) andhigher ratio of Chl contents between the3rd, 4th, sib leaf from top and the flagleaf (Fig. 3) compared with the controls.The above results indicate that hybrid rice leaf senescence is related withsink/source ratio.