华北平原银杏人工林蒸腾耗水特性及其环境响应.

To investigate the characteristics of transpiration water consumption of Ginkgo biloba L. in the North China Plain, the Granier-type thermal dissipation probes were used to measure sap flow density in growing season of 2019 (Apr.1-Oct.31), and the environmental factors including solar radiation(Rs), air temperature(T), relative humidity(TH), soil temperature, soil humidity and wind speed were measured synchronically, aimed to study the stem sap flow of Ginkgo biloba L. in response to environmental factors. The results showed that the sap flow of Ginkgo biloba L. lasted about 194 days form April 10 to October 20. Sap flow density displayed an obvious pattern with the biggest in a sunny day, next in a cloudy day and finally in a rainy day. The diurnal changes of the sap flow density presented a typical single-peak curve under a sunny day, while it undulated widely under cloudy or rainy days due to the fluctuation of solar radiation. Transpiration water consumption in the whole growing season for the single plant of Ginkgo biloba L. was 1468.59 kg, and daily average was (6.16±3.32) kg·d–1, daily average water consumption for each month (April to October) was (2.40±1.50), (7.64±1.35), (7.78±2.03), (8.34±2.35), (8.38±3.05), (6.64 ±2.03) and (2.39±1.89) kg·d–1 respectively. Though the stand water consumption of Ginkgo biloba L. in growing season was 244.81mm, lower than the rainfall, seasonal water shortage still existed, especially in June. The partial correlation analysis showed stem sap flow density at the hour level was significantly correlated with VPD and Rs(P＜0.01), reflecting air temperature, relative humidity and energy level. While at the month level, monthly changes of daily average transpiration water consumption was significantly affected by stomatal conductance and soil temperature. There were seasonal differences on correlation degree, the highest correlation between environmental factors and sap flow appeared at the vigorous growth stage, while the lowest appeared at the early growth stage, soil humidity excluded, which had a extremely significant stress(P<0.01) on sap flow at the early growth stage. [ABSTRACT FROM AUTHOR]