影响树木蒸腾耗水的外部因子研究进展

国内外研究表明,影响树木蒸腾耗水的外部因子主要由2部分构成:一是土壤因子,二是气象因子,包括光照、温度及空气相对湿度等。分析得出这两类因子影响树木耗水的一般规律为:(1)在土壤水分超过树木日需求量平均值过多时,叶片气孔在数小时内迅速关闭,导致树木蒸腾耗水量曲线呈下降趋势;在土壤水分低于树木日需求量平均值过多时,树木的生长受到限制,叶片水势下降,导致蒸腾耗水也相应下降。(2)在一定范围内,树木蒸腾耗水量会随着光照强度、大气温度的增加而增大,随着空气相对湿度的增加而减少。同时,这些因子间的互相作用也影响着树木的耗水。

Advances in the Researches of Exterior Effect Factors on Tree Water Consumption

On summing up the present development of water consumption of trees,it showed that the exterior factors of water consumption consisted of two aspects.One was soil factors and the other was weather factors,including the intensity of the radiation,the temperature and relative atmosphere humidity.Commonly the rule of the two exterior factors of water consumption was obtained: first,when the water content of soil was more than the average content,stomata of leaves shut up within several hours,which led to the decrease of water consumption of trees.On the contrary,when the water content of soil was less than the average content,the result could lead to the decrease of water consumption of trees.Second,to some extents,with the increasing of the intensity of the radiation and the temperature,water consumption of trees increased.However,with the increasing of relative atmosphere humidity,water consumption of trees decreased.All this can provide evidence of following experiments about mechanisms of water consumption.Also,some problems of researching on exterior factors of water consumption of trees were pointed out.