晚播小麦源库调节对籽粒灌浆期光合物质分配及产量因素的影响

 采用#+（14）C示踪方法对源库调节与晚播小麦籽粒灌浆期光合物质分配的关系进行了研究。晚播小麦在籽粒灌浆期旗叶的光合物质主要用于穗部籽粒生长；倒二叶光合物质亦主要供给籽粒，但向茎秆和根系中的分配增多；倒三叶是标记的三叶中光合物质向根系分配比例最大，向籽粒分配比例最小的叶片。研究表明，源库调节能影响到晚播小麦籽粒灌浆期的光合物质分配。穗库容降低，各叶片光合物质向穗部籽粒分配比例减少，向根系、茎叶中分配增多；叶源量减少，一般则向穗部籽粒分配比例增多。不同类型品种叶片光合物质在植株各器官间的分配受源库调节的影响程度不同。晚播小麦源库调节对穗粒数、粒重及其它穗部性状的影响因不同类型品种而异。相对减少源对鲁215953、鲁麦5号、鲁麦7号和鲁麦14号的穗粒数、粒重影响较小，但使鲁麦15号和辐63的穗粒数和粒重明显降低。

Partitioning of~(14) C-photoassimilates During Grain Filling,Yield Components and Their Relation to Source-sink Manipulation of Late-sown Winter Wheat

The study investigated the partitioning of14 C-photoassimilates during grain filling and its relation with source-sink manipulation of late-sown winter wheat with the aid of 14 CO2- tracer. Patterns of 14 C-photoassimilates partitioning indicated that the wheat grain was dominant sink at grain filling, but the difference existed among the three most upper -leaves in their 14 C-partitioning. As for the flag leaf, most of its photoassimi-lates was used for the growth of wheat grains. Although the large part of photoassimilates produced in the top second leaf was also translocated to the wheat grains, the partitioning to stem internodes and roots was increased obviously as compared with the flag leaf. The top third leaf was the leaf, the photoassimilate partitioning of which to roots was the largest and to grains the smallest in the three leaves labelled with 14 C. Source-sink manipulation could regulate the partitioning of photoassimilates during grain filling of the wheat. Partitioning of the photoassimilates of each leaf to the grain was decreased and that to roots , stem and leaves was increased when the sink capacity of wheat ear was decreased. Otherwise,partial removal of leaf source tended to enhance markedly the proportion of photoassimilate partitioning of the leaf remaining to the grain. The degree to which photoassimilate partitioning to each part of the plant was influenced by source-sink manipulation differed between the two varieties. Source-sink manipulation could affect the grains per ear,grain weight and other ear traits,but the magnitude of this effect was dependent on the varieties of wheat. Partial removal of leaves had little influence on grains per ear and grain weight in wheat varieties Lu 215953, Lumai 5,Lumai 7 and Lumai 14, which showed that the source supplied sufficiently. Removal of leaves in part made grains per ear and grain weight decrease significantly in Lumai 15 and F 63,which suggested that the major yield-limiting factor arose from or occurred in the source supply.