河西地区几种中生植物的蒸腾和传导率与叶内外环境的关系

用LI-1600稳态气孔仪，测定了河西地区分布较广的五种木本植物的蒸腾和传导率及环境因子。只要光照不低于气孔开启所需的强度，植物蒸腾率最高点之前的高低变化与叶温上升的速率无关，而仅与每一时刻叶温高低密切相关。在种内，蒸腾率大致随叶的厚度和单位叶面积的栅栏组织表面积的增大而提高。但种间则无此相关性。同一样本叶的上下表面蒸腾率之比与其气孔数之比相对应，而种间则毫无关系。环境条件大致相同情况下，二白杨(Populus kansuensis)全天蒸腾量为78.2gH2O·dm-2，沙枣(Elaeagnus angustifolia)为40,4gH2O·dm-2。分别是箭杆杨(P.nigra var.thevestina)的2.5和1.3倍。同一灌溉条件下，梨光杏(Prunus armeniaca var.glabra)为26.7gH2O·dm-2，比毛杏(P.armeniaca var.ansu)高0.6倍。

Transpiration and Conductivity Rate of Plants in He-Xi area in Relation to Internal and External Environmental Factors of Leaf

The transpiration and conductivity rate of five kinds of plants widely distributed in He-Xi area and the environmental factors were measured by LI-1600 Steady State Porometer. When light intensity was not lower than that required for stomata opening, the change before peak point of transpiration rate was ,lot related to increasing rate of leaf temperatrue, but it was related positively to leaf temperature. The transpiration rate increased with increasing of the leaf thickness and the surface area in palisaoe tissue per unit leaf area within species, but not between species. The ratio of transpiration rate of upper to lower leaf surface within species was related to the ratio of number of stomata on them but no relationship was noted in interspecies.