花前干旱复水对冬小麦光合特性、产量和水分利用效率的影响

Effects of Anthesis Drought and Rehydration on Photosynthetic Characteristics,Yield and Water Use Efficiency of Winter Wheat

为了明确冬小麦花前光合特性、产量及水分利用效率对干旱及复水的响应,选用“周麦22”为试验材料,通过移动防雨棚下桶栽控水的方式,在足墒播种、安全越冬基础上为拔节期和抽穗期间施加不同的水分控制条件,考察冬小麦的光合特性、产量和水分利用效率(WUE),探讨作物干旱复水机理,以期为冬小麦抗旱高产稳产提供理论和技术支撑。取得主要结果如下:①净光合速率(Pn)和气孔导度(Gs)变化趋势保持高度一致,皆随着干旱程度的加重以及干旱时间的增加而显著降低。且干旱对不同生育期影响表现为:连续干旱>抽穗期>拔节期。在复水后,只有单阶段轻旱处理可以恢复到正常水平,其中抽穗期恢复程度最高。②短期干旱条件下产生非气孔限制因素的干旱程度是重旱,长期干旱条件下则是中旱和重旱。③相比之下短期轻旱减产不显著,且产量随着干旱程度加重和干旱时间增加而显著降低,抽穗期干旱要比拔节期产量高。在经历轻旱和中旱复水后,冬小麦水分利用效率明显提高。综合研究认为,冬小麦花前短期轻旱能够在不显著降低产量的情况下增加水分利用效率,在抽穗期遭受干旱复水后补偿效应更高,同时应避免连续干旱。

In order to clarify the photosynthetic characteristics,yield and water use efficiency of winter wheat in response to drought and rewatering,“ZhouMai 22”is selected as the test material by controlling the water of the wheat in bucket under a rainout shelter.On the basis of safely wintering different water control conditions are applied for the jointing stage and the heading period,which are 70%~80%of the water holding capacity of the field(complete irrigation),60%~70%(light drought),50%~60%(medium drought),40%~50%(heavy drought).The photosynthetic characteristics,yield and water use efficiency(WUE)of winter wheat are investigated to explore the mechanism of drought and rehydration of crops so as to provide theoretical and technical support for drought resistance,high yield and stable yield of winter wheat.The main results are as follows:①The trend of net photosynthetic rate(Pn)and stomatal conductance(Gs)remains highly consistent,both of which decrease significantly with the increase in drought and the increase in drought time.The effects of drought on different growth stages are as follows:continuous drought>heading stage>jointing stage.After rehydration,only single-stage light drought treatment can return to normal levels,and the degree of recovery at the heading stage is the highest.②The threshold of drought degree for non-stomatal limiting factors under short-term drought conditions is heavy drought,and the threshold for long-term drought conditions is moderate drought.③In contrast,short-term light drought and yield reduction are not significant,and the yield decreases significantly with the increase in drought degree and drought time.The drought at the heading stage is higher than that at the jointing stage.After experiencing light drought and re-watering,the water use efficiency of winter wheat is significantly improved.According to the comprehensive study,short-term light drought in winter wheat can increase water use efficiency without significantly reducing yield,and the compensation effect is higher after drought rehydration at the heading stage,and continuous drought should be avoided.