不同积水处理下乌拉苔草蒸腾速率日变化及其与环境因子的关系

Diurnal Variation of Transpiration Rate of Carex meyeriana and Its Relationship with Environmental Factors under Different Water Conditions

在相同的光照、相对湿度、温度和风速等自然环境下,对相同土壤条件下的乌拉苔草湿地进行不同水分的处理,以桶(高50cm、直径40cm)中水分为基准,设为满水(干1)、半水(干2)、干旱(干3)3个处理,以自然状态下的土壤为对照。对乌拉苔草叶片的蒸腾速率、气孔阻力、光合有效辐射、空气温度、叶片温度、相对湿度、风速及大气中CO2的体积分数等指标进行了测定。结果表明:不同积水条件下,蒸腾速率的日变化与正弦曲线相似;气孔阻力的日变化呈现单峰形变化,但峰值不同,干2峰值最小,不同处理的峰值出现的时间相同。从时间上看,气孔阻力受水分的影响,与对照相比提前达到最大值。干1、干2、干3处理的蒸腾速率和气孔阻力呈显著的负相关,风速和蒸腾速率呈显著的正相关;干2、干3处理的光量子通量密度和大气温度呈显著的正相关;干3处理的蒸腾速率和光量子通量密度呈显著的正相关。

Different water treatments were conducted to Carex meyeriana wetland with similar soil under the same natural conditions of light, relative humidity, temperature and wind speed. Three treatments, full of water （ called T1 for short）, semi - full of water （ T2）, and drought （ T3 ）, were designed according to the water volume in a bucket, and the wetland under natural condition was used as control. The transpiration rate, stomatal resistance, temperature of leaves of Carex meyeriana as well as photosynthetically available radiation （PAR）, air temperature, relative humidity, wind speed, atmospheric CO2 concentration were determined. Results showed that the diurnal variation of transpiration rates of Carex meyeriana under different water conditions showed a proximate sinusoid, and the diurnal variation of the stomatal resistance presented a unimodal curve. The peak values were not equal, that of T2 was the lowest, while the peaks occurred at the same time. Water content had a certain effect on stomatal resistance. The stomatal resistance reached the maxima ahead of the control. Transpiration rates of these three treatments showed a significantly negative correlation with stomatal resistance, and wind speed presented a significantly positive correlation with transpiration rate. Light - photon flux density for T2 and T3 was positively correlated with air temperature, while that for T3 showed a significant positive correlation with transpiration rate.