不同灌水梯度下沙棘液流特征与环境因子的关系

Relationship between the characteristics of Hippophae rhamnoides fluid flow and environmental factors under different irrigation gradients

以砒砂岩为母质发育的栗钙土作为供试土壤,沙棘作为供试树种,基于茎热平衡法(SHB)在温室内研究不同灌水梯度下T1(田间持水量θFC25%)、T2(θFC40%)、T3(θFC55%)沙棘液流速率变化特征。采用HOBO小型气象站监测环境因子,研究沙棘液流速率对环境因子的响应关系。结果表明:(1)沙棘液流速率除明显的昼夜变化外,还伴有"光合午休"现象,液流变化曲线呈双峰形;(2)沙棘液流速率与土壤含水率呈正比,液流速率和日累积量为T1.

Chestnut soil developed with arsenic sandstone as its parent material was used as a test soil and Hippophae rhamnoides was used as a test tree species to study the change characteristics of the fluid flow rates of H rhamnoides under different irrigation gradients,T1(field water holding capacityθFC25%),T2(θFC40%),and T3(θFC55%),based on a stem-heat balance method in a greenhouse.A small HOBO weather station was used to monitor environmental factors and study the response of the H.rhamnoides fluid flow rate to environmental factors The results showed the following:(1)While it showed significant day-night changes,the fluid flow rate of H rhamnoides was accompanied by heat dormancy.The curve of fluid flow change was bimodal.(3)The fluid flow rate of H.rhamnoides was positively correlated with soil moisture content.The sap flow rate and daily accumulation was lowest in T1 and greatest in T3,but the difference between T2 and T3 was small.(2)Under different irrigation gradients,the stem flow rate of H.rhamnoides was positively correlated with photosynthetically active radiation and air temperature,and negatively correlated with air humidity.The absolute value of correlation between fluid flow rate and environmental factors under different irrigation gradients was lowest in T1 and greates in T2.The value of the regression equation R2was also lowest in T1 and highest in T2.The H.rhamnoides sap flow rate was maintained at a high level under the T2 gradient,and the degree of response to environmental factors was highest under this gradient.Temperature was the leading factor affecting the fluid flow rate of H.rhamnoides.