干旱复水激发玉米叶片补偿效应的生理机制

采用盆栽控水试验,在旱后复水条件下,于苗期对2个不同抗旱性玉米品种叶片生理生化指标进行了测定,结果表明:干旱导致细胞膜结构破坏、叶绿素含量及光合作用下降,抗旱性强的品种变化较小;渗透调节物质和保护性酶活性增加,抗旱性强的品种升幅较大.复水后细胞膜结构迅速恢复,保护性酶活性和可溶性糖含量继续增加,叶绿素含量、光合速率、Fv/F0和Fv/Fm等光合作用参数出现超补偿现象.中度干旱10 d后复水激发了作物的生理补偿效应,主要生理机制是干旱复水后细胞膜结构迅速修复和叶绿素含量的超补偿增加,大大提高了光合作用的潜力和速率;前期干旱锻炼增强了玉米抗旱能力,抗旱品种表现出较高的超补偿效应,有利于适应干湿交替和低水多变的环境,实现节水高产.

The Physiological Mechanism of Compensation Effect in Maize Leaf by Re-watering after Draught Stress

Physiology indexes of two different drought-resistant maizes were studied during water stresses and re-watering in seedling which were cultivated in pots.The results showed that drought lead to damage of cell-membrane, the decrease of chlorophyll content and photosynthesis.The cultivar which is more resistant drought, testify a small changes.Increase in osmosis adjustment substance and the activities of antioxidant enzymes, and the trend becomes more dramatic along with the trait of abilities.After re-watering, the cell-membrane structure all recovery fast,the activities of antioxidant enzymes and Ss content still grow up, the Chlorophyll content,P_n,F_v/F₀,F_v/F_m and so on appear a compensative effect, the change of which is more higher in more-resistant than less-resistant cultivar.The re-watering 10 days after middle water stress make physiology compensative effect, those phenomena can be accounted by the increase of photosynthesis super-compensative effect after the recovery of cell-membrane, which is because of the strength of photosynthetic potential and rate during rapid functional of cell-membrane and increase of chlorophyll content, drought-resistant of cultivars have more ability.The result which shows a increase ability of resisting the drought after re-watering, can be propitious to acclimation the environment of water levity,achieve the saving water and high yield.