不同土壤肥力下冬小麦春季干旱的复水补偿效应研究

 【研究目的】为探明冬小麦春季旱后复水补偿效应及其对土壤肥力的响应；【方法】采用盆栽试验，对生长在不同土壤肥力条件下的冬小麦，于返青、拔节期进行不同程度干旱复水处理；【结果】返青期中度干旱，在高肥力下复水15天时，叶绿素含量已超过对照水平，复水5天后，光合速率超过对照；中、低肥力下，叶绿素含量和光合速率分别在复水15天、20天时比对照略有增加。拔节期中度干旱只在高肥力下复水20天后，光合速率比对照略有增加；其他处理的叶绿素含量和光合速率均未达对照水平。除低肥力下重度干旱外，返青期旱后复水处理与对照相比，产量均无明显降低，收获指数和水分利用效率明显提高，在高、中肥力下中度旱后复水产量还略有增加；拔节期旱后复水处理与对照相比，产量明显降低，收获指数和水分利用效率下降。【结论】冬小麦春季受旱复水后，光合速率比叶绿素含量更容易恢复；返青期旱后复水比拔节期旱后复水在产量和水分利用效率上表现出更强的补偿效应，这主要缘于收获指数的增加；提高土壤肥力可增强冬小麦旱后复水的补偿效应，中、高肥力下返青期中度旱后复水更有利于产量及水分利用效率的提高。

Studies on Compensation Effects of Rewatering on Winter Wheat Suffering from Droughts During Spring Under Different Soil Fertility Conditions

【OBJECTIVE】The study was performed to explore the compensation effects of rewatering on winter wheat suffering from droughts during spring under different soil fertilities. 【METHOD】Through pot experiments with high, medium and low soil fertilities, drought stresses were imposed on winter wheat initiating at turning-green stage and jointing stage, and ending with rewatering at the beginning of the next stage. 【RESULTS】Chlorophyll content and photosynthetic rate of winter wheat suffering from medium drought at turning-green stage showed obvious increases at 15 and 5 days after rewatering under high soil fertility, respectively, while they exhibited slight increases at 15 and 20 days after rewatering under medium and low soil fertilities. Photosynthetic rate of winter wheat suffering from medium drought at jointing stage only demonstrated weak increase at 20 days after rewatering under high soil fertility. Chlorophyll content and photosynthetic rate of the other treatments never reached the level of the control. Except the treatment of severe drought under low soil fertility, rewatering winter wheat suffering from drought at turning-green stage showed insiginificant decrease in yield, but noticeable increases in harvest index and water use efficiency (WUE). The yield of rewatered winter wheat suffering from medium drought even exhibited slight increase under high and medium soil fertilities. Yield, harvest index and WUE of rewatered winter wheat suffering from droughts during jointing stage demonstrated obvious decreases.【CONCLUSION】Rewatering after drought at turning-green stage exhibited stronger compensation effects on yield and WUE, which might result from the higher harvest index. Improving soil fertility could enhance compensation effects of rewatered drought-stressed winter wheat. Rewatering winter wheat after medium drought under high and medium soil fertilities during turning-green stage would be more favorable to improve yield and WUE.