林业科学2019，Vol.55Issue(2)：22-32,11.DOI:10.11707/j.1001-7488.20190203
西藏拉萨河谷区藏川杨和北京杨树干液流特征及其对环境因子的响应
Characteristics of Stem Sap Flow of Two Poplar Species and their Responses to Environmental Factors in Lhasa River Valley of Tibet
摘要
Abstract
[Objective] In this study,the dry-wet seasonal variation characteristics of sap flow of the two afforestation poplar species in semi-arid Lhasa river valley,and the environmental impact factors were investigated in order to provide a theoretical base for species selection for vegetation reconstruction in the river valley.[Method] The Granier's thermal dissipation probe was employed to continuously measure the stem sap flow of Populus beijingensis and Populus szechuanica during the wet and dry seasons.At the same time,environmental factors,such as solar radiation (Q),air temperature (Ta),soil water content (SWC),and vapor pressure deficit (VPD),were recorded.[Results] The main meteorological factors in the Lhasa river valley were quite different in wet and dry seasons.The Q,Ta,SWC,and VPD values during the wet season were higher than that in the dry season,and the average of them in the dry season wrer around 60％ of those in wet season.In both seasons,the sap flow velocity in P.beijingensis was lower than that in P.szechuanica.The sap flux density of P.beijingensis was 71％ and 58％ lower than those of P.szechuanica during the dry and wet seasons,respectively.During the dry season,the sap flux density of two poplars declined by 65％ and 76％ compared with that in wet season.The main environmental factors of Q and VPD had less influence on the stem sap flow of P.beijingensis than on that of P.szechuanica.[Conclusion] In the Lhasa river valley area between dry and rainy season,the sap flux density of two poplar species all had obvious circadian rhythm.However,there were significant differences in peak value,daily average value,start-up time and the impact environmental factors between the two species,especially in the dry season.P.szechuanica,as native tree species,showed a stronger adaptability.关键词
拉萨半干旱河谷/树干液流/热扩散法/环境因子/杨树Key words
semi-arid valley of Lhasa/sap flow/thermal dissipation probe/environmental factors/Populus分类
农业科技引用本文复制引用
辛福梅,闫小莉,张长耀,贾黎明..西藏拉萨河谷区藏川杨和北京杨树干液流特征及其对环境因子的响应[J].林业科学,2019,55(2):22-32,11.基金项目
国家自然科学基金项目(31460192). （31460192）
