小麦籽粒发育初期土壤水分亏缺对植株各部位光合作用的影响

小麦开花后5～16天内给予不同程度的土壤干旱处理。无论轻、中或重度干旱均不同程度地释低了植株的净光合率,但不同器官或部位对干旱的反应不同,上部器官的光合受影响较小,故随着干旱的加重在全株光合中所占比例逐渐增加。恢复灌水后,曾受轻度及中度干旱的植株,中、上部器官的光合有补偿性增强,因而可能减轻产量的损失。

EFFECT OF SOIL DROUGHT IN THE EARLY STAGE OF GRAIN DEVELOPMENT ON THE PHOTOSYNTHESIS IN THE VARIOUS PARTS OF WHEAT PLANT

The effect of soil drought in early stage of grain development on the photosynthesis in various parts of wheat plant, cv. Xiannong 68-3, was investigated with a ~(14)CO_2 labeling technique, The results indicated that net photosynthesis of whole shoot was decreased by all the soil drought treatments, but different organs or parts of the plant respond differently. The upper parts were less affected than the lower parts, so the contribution proportion of upper parts to total photosynthesis increased gradually with aggravation of drought. One week after resumption of normal water supply, the photosynthetic rate of the middle and upper parts that had been subjected to mild or moderate drought attained or even surpassed that of the control, therefore the crop might compensate for some loss of the yield. The plant that had been subjected to heavy droughtwere not able to recover after being rewatered.