调亏灌溉对冬小麦不同生育阶段光合速率的影响

为给冬小麦调亏灌溉（Regulated deficit irrigation,RDI）指标与模式的建立提供理论依据和技术参数,在防雨棚条件下,采用子、母盆栽方法,以冬小麦为试验材料,分析了RDI对冬小麦不同生育阶段光合速率（Pn）的影响,并对其进行了模拟,以探寻适宜的水分调亏阶段（时期）和调节亏水度。结果表明,冬小麦返青至拔节期水分调亏对Pn无显著影响;拔节至抽穗期轻度水分调亏的Pn未受显著影响,复水后补偿效应显著;中、重度调亏的Pn受到显著抑制,复水后虽有补偿效应,但与对照差异不显著;抽穗至灌浆期轻度水分调亏对Pn无显著影响,中、重度水分调亏的Pn受到强烈抑制,复水后补偿效应较弱,补偿时间也有限。据此认为,冬小麦RDI的适宜阶段为拔节期以前,适宜的调亏度为50%～65%FC（Field capacity,FC）;拔节至抽穗和抽穗至灌浆期也可轻度调亏,调亏度为60%～65%FC。

Effect of Regulated Deficit Irrigation on Photosynthesis Rate at Different Growth Stages of Winter Wheat

Under conditions of rain proof shelter and cultivated in pots with winter wheat(Triticum aestivum L.), the experiment for Regulated Deficit Irrigation(RDI) was conducted to investigate the effects of RDI on photosynthesis rate at different growth stages of winter wheat, to seek for the suitable stages of RDI and degree of water deficit, and to offer technique parameters for the establishment of RDI indices and model in winter wheat. A two factor (growing stages and degrees of water deficit) randomized block design was employed in pot culture. The results showed that there was no significant effect of water deficit from green returning to jointing stages on photosynthesis rate in winter wheat; photosynthesis rate was not restrained obviously in light water deficit period from jointing to heading stages, and there was a super compensation effect on photosynthesis rate after re watering, but photosynthesis rate was restrained obviously in medium or severe water deficit period, although there was a compensation after re watering, there was no obvious difference between photosynthesis rate in water deficit treatments and that in CK; while there was no significant effect of light water deficit on photosynthesis rate from heading to filling stages, but photosynthesis rate was restrained severely in medium or severe water deficit period, and there was only a weaker compensation effect in photosynthesis rate after re watering. Therefore, it could be suggested that the suitable growth stages to impose RDI in winter wheat was before jointing stage, and the suitable degree of water deficit was 50% ~65% FC; and light water deficit could be applied at both from jointing to heading stages and from heading to filling stages, the suitable degree of water deficit was 60% ~65% FC.