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.