【摘要】 基于热平衡原理,利用Flow32-1K(Dynamax,USA)茎流仪在晋中盆地太谷县对不同直径枝干的梨树液流变化进行测定,分析了枝干液流与光合有效辐射、温度、大气湿度、风速和饱和水汽压差等环境因子的关系。结果表明,在日尺度上,梨树枝干液流日变化表现为早晚低、中午高的单峰曲线状;液流速率随枝干直径的增加而增大,枝干叶面积越大,液流速率也越大;梨树枝干液流与光合有效辐射的相关性最高(P<0.01),与风速不相关(P>0.05)。在季节尺度上,生长期早期(5-7月)液流流速快速上升,生长后期(8-10月)明显下降。枝干液流日平均值的季节变化可用高斯方程描述,最大日均液流出现在176d(7月28日)。整个生长季梨树枝干液流受环境因子季节变化的影响。研究结果对提高该地区梨树果园水资源利用效率具有重要意义。更多还原

【Abstract】 Based on the principle of the heat balance,using stem-flow gauges of Flow32-1 K（Dynamax,USA）,the sap flow variation was measured in a pear orchard of Taigu County,Shanxi,and the relationship between the sap flow and environment factors,including photosynthetically active radiation(PAR,μmol m^-2·s^-1),air temperature（T,℃）,humidity（H,%）,wind speed(WS,m·s^-1),and atmospheric vapor pressure deficit（VPD）,was analyzed at daily and seasonal scales.As a result,in daily scale,the diurnal variation of the sap flow showed a single peak curve,with a low value in the morning and evening,a high value at noon.The sap flow rate increased with the stem diameter and the leaf area increasing.Among the correlations between the sap flow and the environmental factors,sap flow was mostly significant with photosynthetically active radiation（PAR）（P<0.01）,but not with the wind speed（P>0.05）.At seasonal scale,the sap flow increased during the earlier growing season from May to July and decreased gradually in the latter growing season from August to October,mostly because of effect of its phonological change.The seasonal changes of the daily average sap flow over the season could be described by Gaussian equation,and the modeled maximum daily average sap flow value occurred on day 176（July 28）.Overall,over the season variation of sap flow rate was integrally affected by the all environmental factors.The research results can bear important implications for enhancing water use efficiency in this area.更多还原