Daily variation in stomatal conductance of wetland paint Alisma orientate The seasonal variation of CO2 flux in a wheat field of the Loess Plateau A Study on Daily Variation of Photosynthesis in Greenhouse Butter head Lettuce Influences of Interplanting Herbage on the Soil Respiration of Apple Orchard in Weibei Loess Plateau A Study on Daily Variation of Photosynthesis in Greenhouse Butter head Lettuce DAILY VARIATION OF GAS EXCHANGE,STOMATAL CONDUCTANCE AND WATER USE EFFICIENCY IN SUMMER LEAVES OF ORMOSIA PINNATA