The main results indicated that : significant differences exist in diurnal average transpiration rate and the range of diurnal transpiration rate ; the transpiration rate of sawtooth oak , amorpha , lalang grass varied with a regular double apex rhythm , but that of the rest varied with a regular single apex rhythm , stomatal conductance play a maximal important role in transpiration rate , temperature ( air temperature , the earth ' s surface temperature ) also influence the transpiration rate ; transpiration rate has prominent negative correlation with the relative air humidity , the biggest coefficient is 0 . 866 笔者对日照沿海防护林几种主要木本植物和草本植物的蒸腾速率和环境因子的关系进行了研究，结果表明： 8种植物日平均蒸腾速率和蒸腾速率日变幅各异；麻栎、紫穗槐和白茅的蒸腾速率日变换呈现出双峰式的变化规律，其它5种植物蒸腾速率表现为单峰式的变化规律；气孔导度影响着植物的蒸腾速率，温度（气温、地面温度）是影响植物蒸腾速率的主要因子；空气相对湿度和蒸腾速率表现为显著或极显著负相关，相关系数高达0 . 866 。
