干旱区荒漠植被茎干液流影响因素研究

Research on Influencing Factors of Stem Sap Flow of Arid Desert Vegetation

植物茎干液流能反映植被水分传输状况,被用于研究植被的生态需水量。因此,分析荒漠植被茎干液的流影响因素对新疆干旱区生态环境的改善有着重要意义。以玛纳斯河流域下游古尔班通古特沙漠南缘典型荒漠植被梭梭和柽柳为研究对象,进行野外数据监测,研究荒漠植被茎干液流速率的日变化特征,分析茎干胸周、各气象因子及地下水潜水埋深对茎干液流速率的影响。结果表明:1梭梭和柽柳茎干液流速率均呈明显的昼夜变化规律,白天液流速率远高于夜间。2液流速率的变化与空气相对湿度呈负相关,空气相对湿度越高液流速率低;气温、总辐射的变化与液流速率的变化呈正相关,气温或总辐射越大时茎干液流速率也越大。3相同试验点的同种植被,胸周较大,茎干液流速率越小,抗旱性强。4地下水埋深越浅,荒漠植被茎干液流速率越大,峰值越高,且峰值出现时间相对滞后。

Plant stem sap flow rate can reflect the situation of vegetation water transmission and can be used to study the ecological water requirement of vegetation.Therefore,there is important significance to analyze influencing factors of stem sap flow of desert vegetation for improving the ecological environment in the arid area of Xinjiang.Taking Haloxylon ammodendron and Tamarix,the typical vegetations in the southern Gurbantunggut Desert of Manasi River Basin,as the research objects,through monitoring data,the diurnal variation of stem sap flow rate of desert vegetation is studied,and the impacts of stem chest,meteorological factors and groundwater buried depth on stem sap flow rate are analyzed.The results show that：1the stem sap flow rates of Haloxylon,Tamarix have obvious diurnal variation law,and the day flow rate is far higher than that night flow rate;2the sap flow rate change is negatively correlated with the relative air humidity,and the higher the air humidity,the lower the liquid flow rate;the change trend of air temperature,radiation and the liquid flow rate is basically the same,the sap flow rate increases with the increase of temperature and the total radiation;3for the vegetation at the same test point,the larger the chest,the smaller the stem sap flow rate and the stronger the drought resistance;4the shallower the groundwater depth,the larger the stem sap flow rate of desert vegetation,the higher the peak value,and the later the peak time.