玉米群体冠层内蒸腾速率与气孔导度的变化特性

为了探明玉米群体内光合特性的变化规律，用Li-1600型稳态气孔仪分别测定了3个不同株型的玉米品种（“四密25”、“农大3138”、“吉单159”）群体冠层内的蒸腾速率和气孔导度的日变化和冠层变化。结果表明：3个品种群体冠层内蒸腾速率的日变化为单峰型，中午12：00达最大值；气孔导率的日变化近似单峰型，在上午10：00达最大值。蒸腾速率和气孔导度的冠层变化均为：上层叶＞中层叶＞下层叶：蒸腾速率与气孔导度呈正相关。 

Varying Characteristics of Transpiration Rate and Stomata Conductance in Maize Canopies

To probe the varying characteristics of photosynthesis in maize canopies, diurnal variation of their transpiration rate and stomata conductance was measured by Li-1600 stomata instrument The result showed that: diurnal variation of transpiration rate took on a single peak curve, and its maximum value reached at 12:00 at noon; diurnal variation of stomata conductance took on an approximately single peak curve, and its maximum value reached at 10:00 in the morning Transpiration rate and stomata conductance of the upper layer leaves were higher than those of the middle layer leaves, which were in return higher than those of the lower layer leaves Transpiration rate was positively correlated with stomata conductance