Effects of Drought Stress and Postdrought Rewatering on Winter Wheat: A Meta-Analysis.

Drought is a major stress that restricts the growth and development of winter wheat (Triticum aestivum L.), and recovery after drought is the key to coping with adversity. So, we used a meta-analysis to quantitatively evaluate the responses of winter wheat to drought stress and rewatering and investigated the differences caused by several moderators (e.g., stress intensity, treatment durations, growth stages, planting methods, and experimental areas). The results show that drought can cause many negative effects on winter wheat. However, in most cases, rewatering can offset these adverse effects. Winter wheat under short-term or mild stress was less affected, and rewatering can restore it to the control level. Net photosynthetic rate (Pn), transpiration rate (Tr), and stomatal conductance (gs) are sensitive to environmental water change. Drought reduced the quantum yield of electron transport (ΦPSII), with insignificant effects on the efficiency of PSII (Fv/Fm). Additionally, the responses to drought and rewatering also varied with different growth stages. The regreening stage and the anthesis-filling stage are both critical water management periods. Rewatering after the jointing stage had no significant effect on leaf area (LA) and plant height (PH). The drought tolerance and recovery ability of field-grown wheat were better than those of pot-grown wheat. Winter wheat planted on the Loess Plateau was less affected than that on the Huang-Huai-Hai Plain and the Middle–Lower Yangtze Plain. Overall, different moderators may lead to different degrees of responsiveness of wheat to drought stress and postdrought rewatering. This study provides a reference for winter wheat to cope with drought stress and a useful guidance to wheat breeding programs. [ABSTRACT FROM AUTHOR]