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蒸腾耗水是植被水分利用的重要方式和重要过程之一,对植物养分输送、生长发育、应对和缓解干旱胁迫以及改善区域微气候等都具有重要意义.研究以半干旱黄土区的油松植被为例,基于四针式热扩散探针法监测树干液流的动态变化,探讨其蒸腾耗水规律,分析油松树种的水分利用方式及对生存环境的适应能力.结果表明,油松的液流速率具有明显的季节性差异,不同月份的液流速率以4月最低,其次为10月、9月和8月,分别为0.024、0.057、0.062和0.071 m L·(cm2·min)-1.液流速率的日变化在各个时期都呈现昼高夜低趋势,夜间液流速率较低,但不为零.在降雨事件影响下,夜间液流量在日液流总量中的比重明显增加,是晴朗天气的3.9倍,而白天液流量所占比重下降31.8%.寒潮期间液流速率表现出相似的变化趋势,对突变环境具有较强的适应能力.油松液流速率与气象因子显著相关,对液流速率影响的大小顺序为:太阳辐射>水汽压亏缺>相对湿度>大气温度.
Transpiration water consumption is one of the important ways and an important process of vegetation water use, which is of great significance to plant nutrient transportation, growth and development, coping with and mitigating drought stress and improving regional microclimate, etc.In this paper, the semi-arid Loess Plateau Pinus tabulaeformis vegetation As an example, based on the four-pin thermal diffusion probe method to monitor the dynamic changes of the trunk flow, to explore the law of transpiration water consumption, analysis of the pine tree species of water use and adaptability to the living environment.The results show that the liquid pine The flow rate had obvious seasonal differences. The flow rates in different months were the lowest in April, followed by those in October, September and August, which were 0.024, 0.057, 0.062 and 0.071 m L · cm 2 · min -1 respectively The diurnal variation of liquid flow rate showed the trend of high night and low night, and the night flow rate was low, but it was not zero. Under the influence of rainfall events, the proportion of night liquid flow in the total daily liquid flow significantly increased , Which was 3.9 times of sunny days, while the proportion of liquid flow during the day decreased by 31.8% .The flow rate during cold wave showed a similar trend of change, and had strong adaptability to abrupt environment.The rate of flow of Pinus tabulaeformis and the meteorological factor were significant Related, right Effect of the flow rate of the order of: solar radiation> VPD> RH> air temperature.