北京园林5种乔木蒸腾模拟及其对环境因子的响应比较

WHOLE-TREE TRANSPIRATION RESPONSES TO CHANGES OF ENVIRONMENTAL FACTORS OF FIVE GARDENING TREE SPECIES IN BEIJING

研究北京市园林常用5种乔木国槐(Sophora japonica)、银杏(Ginkgo biloba)、白蜡(Fraxinus chinensis)、杜仲(Eucommia ulmoides)、臭椿(Ailanthus altissima)等植物蒸腾作用与周围环境的气象因子(温度、湿度、太阳有效辐射)及植株叶面积指数相关关系,利用Javis公式计算冠层气孔阻力,再用PM公式计算冠层蒸腾速率、植株日蒸腾量,分析不同乔木的冠层气孔导度对环境主驱动因子的响应规律.结果表明:在5种被观测乔木中耗水量国槐最大,白蜡最低,植株蒸腾量从大到小依次为国槐、银杏、杜仲、臭椿、白蜡(P<0.01).从植物叶片气孔导度及蒸腾量与环境驱动因子太阳辐射及水气压亏缺的相关关系看,在保障土壤水分条件较好时,国槐长势好于其他4种乔木,但对水分利用不够经济,在干旱情况下不能有效节水.

To investigate water use characteristics of gardening tree species in Beijing,sap flows in Sophora japonica,Ginkgo biloba,Fraxinus chinensis,Eucommia uloides and Ailanthus altissima were measured continuously with a thermal dissipation probe.Environmental factors,such as photosynthetically active radiation（PAR）,air temperature and relative air humidity,were monitored.Whole-tree transpiration was simulated by JAVIS model and PM equation.Data showed that whole-tree transpiration in Sophora japonica was the highest,while that for Fraxinus chinensis the lowest.Correlations between whole-tree transpiration,canopy stomatal conductance and environmental driving factors radiation and vapour pressure deficit were significant at daily scales.Sophora japonica grew well under sunny,light dry condition,while Ginkgo biloba,Fraxinus chinensis,Eucommia uloides and Ailanthus altissima grew well under medium sunny,humid conditions.