不同时期水分亏缺对冬小麦根系效率及后期抗旱性的影响

Effect of Water Deficit at Different Growth Stages on Root Efficiency and Drought Tolerance in Late Growing Stage of Winter Wheat

采用盆栽试验方法研究了不同生育期水分亏缺对冬小麦根系效率、后期抗旱性和水分利用效率的影响。试验设3个水分亏缺处理时期:越冬—拔节期、返青—拔节期、拔节—抽穗期;每个时期水分亏缺程度均为田间持水率的45%～50%。设置对照(CK)土壤含水率为田间持水率的70%～75%。结果表明,返青—拔节期水分亏缺提高了小麦的根系效率和水分利用效率。越冬—拔节期和拔节—抽穗期水分亏缺显著减少了水分消耗,也提高了小麦的根系效率,但由于显著降低了籽粒产量,水分利用效率没有提高。在花期,3个水分亏缺处理小麦旗叶的叶绿素荧光参数实际光化学量子产量、表观光合电子传递速率、光化学淬灭系数和非光化学淬灭系数值,在停止供水5d后,均显著高于对照。可见,3个水分亏缺处理均提高了小麦的耐旱性,在自然干旱条件下比对照具有较强的光化学活性。

A pot experiment was conducted to clarify the effect of water deficit at different growth stages on root efficiency and water use efficiency of winter wheat.Plants were subjected to three water deficit stages： over-wintering-jointing stage,returning green-jointing stage,jointing-heading stage,plants were maintained at 45%~50% FWC（field water capacity） at every stage.After water deficit treatment terminated,plants were maintained at 70% FWC.The control plants（CK） were maintained at 70% FWC in the experimental period.The results showed that water deficit treatments of returning green-jointing stage improved significantly root efficiency and water use efficiency of winter wheat.Water deficit treatments of over-wintering-jointing stage and jointing-heading stage improved significantly root efficiency of winter wheat and reduced significantly water consumption,but water use efficiency was unaffected due to reducing grain yield.The values of chlorophyll fluorescence parameters,i.e.,effective PSⅡ quantum yield,apparent rate of photosynthetic electron transport,coefficient of photochemical quenching and coefficient of non-photochemical quenching,were significantly higher in three water deficit treatments than the control 5 days after withholding water at anthesis.This means that water deficit treatments improved drought tolerance ability of wheat,resulting in improved photosynthetic capability.