热带雨林冠层树种绒毛番龙眼树冠蒸腾及其与气候因子的关系

Canopy Transpiration and Its Relationship with Meteorological Factors of Pometia tomentosa in Tropical Rain Forest

利用依据热量平衡原理设计的热扩散探针(TDP),在自然条件下测定了西双版纳热带季节雨林顶级树种绒毛番龙眼(Pometia tomentosa)活体树冠蒸腾量,并定量评价了树冠蒸腾与主要气候因子PAR和VPD的关系。结果表明:绒毛番龙眼树冠蒸腾的昼夜变化趋势与PAR和VPD变化趋势一致,基本呈单峰型。白天蒸腾显著高于夜晚,各月白天的蒸腾量约占全天的80%～90%。树冠蒸腾总量呈现明显的季节变化特征,雨季、雨季末和干热季蒸腾总量平均值分别为530.32、460.81、222.80 kg.m-2.d-1。树冠蒸腾与VPD之间幂指数曲线拟合最好,而与PAR之间直线拟合最好;树冠蒸腾的变化更多地依赖于PAR地变化。

The tree canopy transpiration of the dominant tree （Pometia tomentosa） in a tropical rain forest in Xishuangbanna was measured by thermal dissipation probe （TDP） , and the relationship between the environmental factors, including photo- synthetically active radiation（PAR） and vapor pressure deficit （VPD）, and canopy transpiration were investigated simulta- neously. The results indicated that the canopy transpirations exhibit similar unimodal patterns with PAR and VPD. Canopy transpiration value in day takes up 80% -90% of all transpiration among different months, and is significantly higher than that in night. The values of the canopy transpiration are 530.32 kg·m-2 ·day-1, 460.81 kg· m-2 · day-1 and 222.80 kg·m-2·day-l in the rainy season, later rainy season and dry hot season, respectively. There are best fitting power exponent curves between the canopy transpiration and VPD and best linear fitting between the canopy transpiration and PAR. The canopy transpiration depends more on PAR.