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林业科学 ›› 2019, Vol. 55 ›› Issue (2): 22-32.doi: 10.11707/j.1001-7488.20190203

• 论文与研究报告 • 上一篇    下一篇

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

辛福梅1,3, 闫小莉2, 张长耀3, 贾黎明1   

  1. 1. 北京林业大学省部共建森林培育与保护教育部重点实验室 北京 100083;
    2. 福建农林大学林学院 福州 350002;
    3. 西藏农牧学院 林芝 860000
  • 收稿日期:2018-03-26 修回日期:2018-12-10 出版日期:2019-02-25 发布日期:2019-03-20
  • 基金资助:
    国家自然科学基金项目(31460192)。

Characteristics of Stem Sap Flow of Two Poplar Species and their Responses to Environmental Factors in Lhasa River Valley of Tibet

Xin Fumei1,3, Yan Xiaoli2, Zhang Changyao3, Jia Liming1   

  1. 1. Ministry of Education Key laboratory of Silviculture and Conservation, Beijing Forestry University Beijing 100083;
    2. College of Forestry, Fujian Agriculture and Forestry University Fuzhou 350002;
    3. Tibet Agriculture and Animal Husbandry University Linzhi 860000
  • Received:2018-03-26 Revised:2018-12-10 Online:2019-02-25 Published:2019-03-20

摘要: [目的]研究西藏拉萨半干旱河谷地带藏川杨和北京杨树干液流的干湿季变化特征及环境影响因素,以期为该地区造林树种选择和合理配置提供科学依据。[方法]运用Granier热扩散探针技术,于2015年旱季和雨季在西藏拉萨半干旱河谷对藏川杨和北京杨的树干液流进行连续观测,并同步测定太阳辐射(Q)、空气温度(Ta)、土壤含水量(SWC)、饱和蒸气压亏缺(VPD)等环境因子。[结果]1)拉萨河谷区主要气象因子在旱季和雨季存在较大差异,雨季的QTa、SWC、VPD等均高于旱季,主要气象因子的平均值为雨季的60%左右。2)藏川杨和北京杨的树干液流日变化表现出昼高夜低的规律,二者在雨季的日变化为多峰曲线,旱季为单峰曲线。旱季和雨季藏川杨液流速率均显著大于北京杨,北京杨液流密度在旱季和雨季相比藏川杨的液流密度分别下降71%和58%;相比雨季的液流密度,2种杨树的液流密度在旱季分别下降65%和76%。3)在旱季和雨季,主要环境因子Q和VPD与2种杨树树干液流间具有显著相关性,且Q和VPD的日变化与2种杨树的液流速率日变化之间存在明显的时滞效应。Q和VPD对北京杨树干液流的影响小于对藏川杨树干液流的影响。[结论]在拉萨河谷区旱季和雨季较大气候差异的环境下,藏川杨和北京杨树干液流速率均具有较为明显的昼夜节律。但2树种树干液流在峰值、日平均值、启动时间以及受环境因子的影响方面均存在明显差异,特别是在干旱季节尤为显著,藏川杨作为乡土树种显示出更强的适应性。

关键词: 拉萨半干旱河谷, 树干液流, 热扩散法, 环境因子, 杨树

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.beijingensisthan 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.

Key words: semi-arid valley of Lhasa, sap flow, thermal dissipation probe, environmental factors, Populus

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