减源对不同穗型小麦品种干物质积累及其运转的影响

Effects of Leaf Removal on Accumulation and Transfer of Dry Matter in Different Spike-type Wheat Varieties

为给小麦育种在源、流、库性状改良方面提供理论依据，以三种穗型的6个小麦品种为材料，研究了减源对不同穗型小麦干物质积累及其运转的影响。结果表明：（1）叶源亏缺导致干物质累积量和穗粒重降低，减源越多、减源叶位越高，二者降低幅度越大；（2）叶源亏缺可以大幅度提高剩余叶源的光合速率和营养器官花前储藏物质对籽粒的贡献率，但其效应不能完全补偿叶源亏缺造成的光合损失；（3）小麦籽粒产量的80％（中穗型和多穗型）～90％（大穗型）来自花后光合产物的积累，叶源是小麦籽粒库扩建的核心光合源；（4）营养器官花前储存物质可以大幅度被调运用于籽粒库的扩建，小麦生育后期叶源的光合速率不但可以被提高，而且随生育期推进而下降的速度也可以减缓；（5）三种穗型小麦比较，在相同减源条件下，大穗型小麦的光合积累量和穗粒重的降低幅度及光合速率随生育期推进的降低幅度远小于中穗型和多穗型小麦，大穗型小麦营养器官花前储存物质对籽粒库的贡献率远小于中穗型和多穗型小麦，且花后光合产物的分配也不够合理，说明大穗型小麦源、流、库性状改良的产量潜力远高于中穗型和多穗型小麦。适当减小叶面积、提高分蘖成穗率、增加群体穗数，以及在群体水平上增源、畅流、扩库，可能是大穗型小麦源、流、库性状改良的方向。

To provide theoretical basis on source-translocation-sink traits improvement for yield breeding, we took multiple ear, intermediate and big ear winter wheat varieties as experimental materials to study the effects of leaf removal on the accumulation and transfer of dry matter in wheat varieties,The results showed that. （1）Dry matter accumulation and grain weight per spike decreased due to leaf re- moval,and the more leaves removed and higher leaf- position, the more setting kernels and grain weight decreased evidently; （2）The net photosynthetic rate of the remnant leaves rose and the contri-bution rate of storage substance in stem and sheath to grain increased significantly after leaf removal, but could hot compensate the loss caused by leafs （3）80% for （intermediate ear and multiple）-90 for （ big ear）of wheat grain yield came from photosynthetic products accumulated after blooming, and leaf source was the core of wheat grain extensions （4）Substance saved in vegetative organs before anthesis could be greatly used for wheat grain extension, and photosynthetic rate in functional leaves could not only be improved but also its declining degree could be slowed down with the advance of growing stages;（5）Comparing the three spike-type wheat varieties, under the same condition of leaf removal, the decrease ranges of dry matter accumulation, grain weight per spike and photosynthetic rate with the advance of growing stages in big ear variety were far less than those in multiple ear variety and intermediate ear variety; the contribution rate of storage substance in vegetative organs before-anthesis in big ear variety was far less than that in multiple ear variety and intermediate ear variety; the distribution of dry matter after anthesis also was not so reasonable in big ear variety, all of which showed that yield potential of traits improvement in big ear variety was far higher than that in multiple ear and intermediateear varieties. To control leaf area properly, increase ear-tillering ratio and the spikelet number of plant population, enlarge sink, level of popalation may be the direction for improve big ear wheat variety. smooth translocation and increase source on the ment in the source-translocation-sink properties of big car wheat variety.