Abstract: Field experiment shows:1.Large difference can be found in the stomatal conductance bet-ween two sides of corn and wheat leaves.The adaxial side of wheat leaves has a largerStomatal conductance,but the abaxial side of corn leaves does.2.The abaxial stomata ofwheat leaves is more sensitive to the environmental variations,whereas the adaxial stomataof corn leaves is.3.When sufficient soil water supply is available,the ratio of stomatalconductance between two sides of wheat leaves is constant (about 1.50),but changes greatlyfor corn leaves.

Key words: Karst area, Cupressus funebris, drought stress, re-watering, active oxygen scavenging system