| 摘要: |
| 【目的】探明热带桉树蒸腾耗水时间变化规律及其与环境因子的关系。【方法】通过热扩散探针法（TDP）于2016年1—12月对海南省儋州林场桉树树干液流进行实时监测，并同步监测气象、土壤水分等相关环境因子。【结果】①雨季桉树液流瞬时变化特征多为“双峰”型曲线，旱季为“单峰”型，雨季液流到达峰值时间在11:00—11:30之间，峰值平均为8.68 mL/（cm2·h），并在15:00—15:30出现第2个液流峰值，平均峰值为8.16 mL/（cm2·h），旱季液流达到峰值时间在13:00—13:30之间，峰值平均为7.45 mL/（cm2·h）；②旱季和雨季桉树液流瞬时速率对相对湿度和大气温度的时滞均为30 min，对光合有效辐射的时滞均为-30 min；③日尺度上桉树平均液流速率为2.06 mL/（cm2·h），最大值出现在7月15日，为4.25 mL/（cm2·h）；最小值出现在11月25日，为0.14 mL/（cm2·h），太阳有效辐射（PAR）、大气温度（Ta）、饱和水气压差（VPD）是影响桉树日均液流的主要环境因子，树木胸径大小与日均液流速率正相关；④桉树月均液流速率的变化特征为“单峰型”曲线，雨季液流速率均值为2.53 mL/（cm2·h），旱季为1.80 mL/（cm2·h），最大值出现于7月，为3.42 mL/（cm2·h），最小值在2月，为1.40 mL/（cm2·h），其中PAR、Ta、VPD是主要影响因子。【结论】热带桉树人工林液流存在明显昼夜与季节节律，不同观测尺度下影响桉树液流速率的主要环境因子均为PAR、Ta、VPD。 |
| 关键词: 桉树； 液流； 气象因子； 土壤水分； 环境因子 |
| DOI：10.13522/j.cnki.ggps.20190080 |
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| 基金项目: |
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| Sap Flow in Tropical Eucalyptus Plantation and Its Response to Environmental Changes |
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WANG Chengcheng, CHEN Liyan, ZHAO Congju
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College of Geography and Environmental Science, Hainan Normal University, Haikou 570100, China
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| Abstract: |
| 【Objective】 Transpiration is controlled by many biotic and abiotic factors and in this paper, we studied the sap flow in tropical eucalyptus under different environments.【Method】The experiment was conducted from January to December in 2016, and the sap flow in the eucalyptus was measured with the thermal dissipation probe under changing environment which was monitored synchronously by a small meteorological station at the Danzhou Forest Farm in Hainan province. 【Result】①Temporal change of the sap flow velocity had two peaks in wet season and one peak in dry season. In wet season, the first peak 8.68 mL/(cm2·h) occurred between 11:00 to 11:30 am followed by the second peak 8.68 mL/(cm2·h) occurring between 15:00~15:30. The mean of the peaks in dry season was 7.45 mL/(cm2·h). ②The instantaneous sap flow rate lagged behind the Rh and Ta by 30 min, and the PAR by -30 min, in all seasons. ③The mean daily sap flow velocity was 2.06 mL/(cm2·h), and the maximum sap flow velocity was 4.25 mL/(cm2·h) occurring in 15th July, and the minimum was 0.14 mL/(cm2·h) occurring in 25 th November. The photosynthetically active radiation (PAR), atmospheric temperature (Ta), vapor pressure deficit (VPD) were the main factors affecting sap flow velocity. The diameter of the tree at the breast height was positively related to daily sap flow velocity. ④The monthly average sap flow velocity had a single peak, with its average in wet and dry seasons being 2.53 mL/(cm2·h) and 1.80 mL/(cm2·h) respectively. The maximum monthly average sap flow velocity was 3.42 mL/(cm2·h) occurring in July, and the minimum was 1.80 mL/(cm2·h) occurring in February, both affected mostly by PAR, Ta and VPD. 【Conclusion】 The sap flow rate in tropical eucalyptus showed seasonal and diurnal period, and its daily and monthly average was affected mostly by PAR, Ta, and VPD. |
| Key words: eucalyptus; sap flow; meteorological factors; soil water content; environmental factors |
