源库关系改变对小麦灌浆期植株光合速率及~(14)C同化物运转分配的影响

选用千粒重大小不同的小麦品种，研究了去除顶端两个小穗对两类品种（大粒品种和小粒品种）千粒重、穗粒数、穗粒重、籽粒平均灌浆速率、单穗平均增重速率、植株光合速率及１４Ｃ同化物运转分配的影响。试验结果表明，去除顶端两个小穗后，两类品种的千粒重提高，穗粒数降低或基本不受影响，但降低比例明显低于去除小穗数的比例。籽粒平均灌浆速率和单穗平均增重速率（分别表征籽粒库容活性和穗粒库容活性）相应提高。结果，两类品种的穗粒重表现为补偿性增长。两类品种比较，小粒品种的增长幅度大于大粒品种。穗粒库容活性增强使得小粒品种灌浆中后期的植株光合速率提高，使两类品种分配到籽粒中的１４Ｃ同化物比例增加。从而表明，无论是植株光合速率还是同化物的运转分配皆受穗粒库容活性的调控，调控方式和幅度因品种类型而不同。但提高其穗粒重的着眼点都应当是提高穗粒库容活性。

EFFECT OF SOURCE SINK MANIPULATION ON PHOTOSYNTHETIC RATE AND PARTITIONING OF 14 C ASSIMILATE DURING GRAIN FILLING IN WINTER WHEAT PLANT

Wheat cultivars of different grain weight (representing small of large grain cultivars respectively) were selected as experimental materials,the effect of removal of top two spikelets on 1000 grain weight,grain number per ear,grain weight per ear,average grain filling rate,average increment rate of ear weight,photosynthetic rate and partitioning of 14 C assimilate during grain filling in winter wheat plant were studied.When top two spikelets were removed at anthesis,the grain weight increased,grain number per ear decreased or unchanges,but the decrease percentage in grain number per ear was much smaller than that in spikelets removed,the average grain filling rate and average in crement rate of grain weight per ear increased accordingly,resulting in compensatory increase of grain weight per ear.Compared with large grain cultivars,the increase degree in grain of small grain cultivars were much higher.Resulting from strenthen sink activity,the photosynthetic rate of small grain cultivars at middle and final stage of grain filling and partitioning of 14 C assimilate into grain of all cultivars were increased.Conclusively,both the photosynthetic rate and the partitioning of 14 C assimilate were controled by sink activity,but the regulation way and degree were dependent on the types of cultivar.