银杏树体茎流变化及其对环境因子的响应

Change of Trunk Sap Flow of Gingkgo(Ginkgo biloba L.)and its Response to Environmental Factors

为了动态地掌握银杏的蒸腾耗水规律,并揭示其生态、生理作用机理,采用热扩散式液流探针(TDP)监测银杏树体不同生长阶段的茎流变化,并通过气象站同步测定环境因子参数。结果表明:在典型的晴天、多云、阴雨天气下,银杏树干茎流的日变化差异显著,日累积茎流通量为晴天>多云天气>阴雨天气;银杏茎流的季节变化趋势呈现为先上升后下降的态势,在新梢生长期的蒸腾耗水量最大,日耗水量可达23L左右。在叶速生期、新梢生长期和叶黄期银杏日蒸腾耗水量的波动明显,其中以新梢生长期最为显著,日间差异最大可达20L。以各阶段日均耗水量来估算,12年生银杏年耗水量大约为2580L;银杏在年生长周期中茎流通量的变化趋势与气温、土壤湿度、土壤温度、相对湿度、光合有效辐射以及降雨量的季节变化趋势基本一致,逐步回归分析表明银杏年生长周期中大气温度是茎流最为主要的影响因子,回归方程达到极显著水平。

In order to be master of the rule of water transpiration of gingkgo （G. biloba）, and open out the mechanism of physiology action, The Thermal Dissipation Probe （TDP） was used in this experiment to monitor the dynamics of gingkgo （G. biloba） trunk sap flow in different growing periods, and an Automatic Weather Station was synchronously applied to measure the environmental parameters. The results indicated that change of sap flow was shown significantly different in fine day, cloudy day and in rainy day, daily cumulative flux of fine day〉cloudy day＇s〉rainy day＇s; The seasonal change trend of sap flow revealed that transpiration flux was the most in Jul., daily sap flow flux could reach around 23L.Daily sap flow flux fluctuating was relatively distinct in May, July and Sep., most distinct in Jul, discrepancy could reach 20L. According to average daily sap flow flux of different growth phases, transpiration flux of gingkgo of 12a was changes of temperature, soil relative humidity, soil temperature, relative humidity, PAR and rainfall. Stepwise regression analyses revealed that temperature was the main environmental factor influencing on sap flow, stepwise regression equation shows it reaches significant level.