榆叶梅等3种园林灌木的蒸腾特性

Characteristics of transpiration in three garden shrubs

在利用LI-6400便携式光合系统测定分析阿克苏市3种园林灌木榆叶梅、红瑞木、紫穗槐蒸腾速率日变化、月变化特征的基础上,研究了光照强度、大气温度、大气相对湿度、大气水势、气孔导度、叶温下蒸汽压亏缺对蒸腾速率的影响,并进行相关性分析,建立了逐步回归模型。结果表明:3种灌木的蒸腾速率日变化均呈早晚低、中午高的单峰曲线,3种灌木蒸腾速率的大小为榆叶梅>红瑞木>紫穗槐,这与自由水含量的高低顺序一致。蒸腾速率的月变化为7月最高,5月和9月较低。水分利用效率的日变化曲线表现为早晨低、中午高、下午降低、傍晚又升高的特点,在生长季节,月变化为5月份最高,7月份最低。在影响蒸腾速率的各因子中,与之相关性最大的为光照强度,相关系数达到0.960,进行逐步回归分析后,3个模型都只含有光照强度一个因子。

Characteristics of daily and monthly variation of transpiration rate of three garden shrub species in Arksu,namely,Prunus triloba,Swida alba,Amorpha fruticosa,were systematically studied by using LI-6400 Portable Photosynthesis System.And based on this investigation,we studied the influence of photosynthetically active radiation（Qp）,air temperature（TA）,relative humidity（HR）,air-water potential,stomatal conductance andvapor pressure deficit on transpiration rate.Furthermore,we carried out correlation analysis and set up a stepwise regression model.The results indicated that the daily variation of plant transpiration rate showed a pattern of single peak with a high value in midday and a low value in the early morning and early evening,and the values of transpiration rate of three shrubs were conformed with the mass of its free-water;monthly variation reached a high value in July and a low value in May and September.Daily variation curve of EW showed that the value was low in the morning,high at noon,afterwards,it began to decrease in the afternoon and increased once more in the evening.During the growing season,monthly variation reached its highest and lowest value in May and July respectively.Among those impact factors,Qp was the most relevant（r=0.960）,the result of stepwise regression analysis showed that three models all contained the only factor Qp.