不同土壤水分供应与施锌对玉米水分代谢的影响

采用盆栽试验研究不同土壤水分状况下及施锌对玉米植株水分状况、水分生理特征的影响。结果表明,干旱胁迫下,玉米叶片含水量和水势降低,植株体内自由水分的含量减少,而束缚水含量略有增加,离体叶片失水速率小;叶片气孔阻力增加,导度下降,蒸腾作用和光合速率受到抑制。施锌后玉米叶片的水势和鲜重含水量没有明显变化,但玉米叶片气孔阻力降低,气孔导度增加,叶片蒸腾速率和光合作用速率加大。干旱胁迫下,施锌对玉米植株体内水分生理代谢有一定的调节作用,但是在土壤水分供应充足时,施锌更能增强玉米水分生理代谢,提高水分利用效率。

Effect of zinc application on physiological response of maize to different soil moisture regimes

Pot experiment under greenhouse condition was conducted using cumulic cinnamon soil and fluvo-aquic soil from North China to study the effect of zinc application on maize plant physiological response to different soil moisture regimes. Results showed that zinc application had a little influence on decreases of water potential, water content on fresh weight, and free water content of maize leaves under drought stress. There was a marked decrease in the water loss rate for detached leaves under drought but it was not affected by zinc application. On the other hand, stomatal resistance and conductance to water vapor, photosynthesis rate, transpiration rate, and water use efficiency of maize leaves were inhibited by soil water deficit, whereas zinc supply could mitigate these adverse effects. The highest photosynthesis rate, transpiration rate, and water use efficiency were found in those leaves under zinc application with adequate soil moisture. Zinc application could mitigate maize plant negative responses to soil drought because zinc application could enhance leaf photosynthesis rate. However, promotion of plant growth and physiological process due to zinc application would be more marked when maize plants were grown with adequate soil water supply.