不同方法测定三倍体毛白杨整树蒸腾的比较

Comparison on the whole-tree water use of hybrid triploid of Chinese white poplar between the whole tree potometer and thermal dissipation probe

为了解热扩散法测定速生林蒸腾耗水的准确性,以整树容器法为对照,利用热扩散式边材液流探针(TDP-30)对5年生三倍体毛白杨整树蒸腾进行测定。结果表明,TDP法与整树容器法测得的整树蒸腾速率具有一致的"单峰型"日变化趋势,且极显著线性相关(R2=0.955)。TDP法较整树容器法测得的整树蒸腾量偏低5.58%。三倍体毛白杨夜间蒸腾显著,两种方法测定的夜间蒸腾量分别为白天的21.24%和31.60%。利用TDP法研究三倍体毛白杨蒸腾耗水规律准确、可靠,日间蒸腾耗水量与实际相符而夜间蒸腾量偏小。

To understand the accuracy of thermal dissipation method in measuring the whole tree water use, a comparison was made in hybrid triploid of Chinese white poplar plantation. The sap flow density of hyrid triploid of Chinese poplar was measured with thermal dissipation probe （TDP）, which was compared with the whole tree potometer measurement. The diurnal variation of sap flow density（ Fs ） measured by TDP and the whole tree transpiration rate（ Tr ） measured by the whole tree photometer was a similar ＂single peak type＂. And there was significant linear relationships （ R2=0.955 ） between Fs and Tr. The average sap flux was 5.58% lower than the daily average transpiration by the whole tree potometer. The ratio of nocturnal and daytime transpiration of hyrid triploid of Chinese poplar was 21.24% and 31.60% respectively by the TDP and the whole tree potometer. As a conclusion, the thermal dissipation method had high reliability in water use pattern study of triploid clones P. tomentosa.