摘要
运用热扩散技术对柠条锦鸡儿根部液流速率(Fs)进行连续测定,同步进行环境要素的实时监测。选择2008年4—10月30天典型晴天日观测数据。结果表明:1)Fs在晴天日表现出典型的宽峰型正态分布,可划分为4个特征差异明显的阶段,反映了大气环境因子对液流的直接驱动效应,以及柠条锦鸡儿叶片气孔行为对液流变化的调控作用。2)液流的变化受多个环境因子共同驱动,其中潜在蒸发散(ET0)综合性强、与Fs相关紧密,是分析液流特征更为可靠的复合型环境变量。Fs与主要环境因子间的耦合关系因时段而异,在早晨启动的液流上升阶段,Fs与太阳辐射、ET0间均呈线性关系,反映了太阳辐射等因子对液流的驱动与对光合作用的激活效应,而在峰值后的下降阶段基本呈Sigmoidal-Hill函数关系;Fs随大气水分亏缺(VPD)的变化与随太阳辐射、ET0的变化趋势相反,表明VPD在达到一定值后启动气孔调节行为以及抑制过度蒸腾耗水的效应。3)柠条锦鸡儿根部Fs与主要环境要素间的变化近似同步,试验期间没有出现典型的时滞现象。4)在整个生长季的大部分时间内观测到柠条锦鸡儿根部夜间持续存在着液流现象,夜间液流量平均占全天液流量的3.83%。试验结果可例证热扩散技术在根部测定液流并用来计算灌木树种单株耗水方法的科学性与优越性。
The sap flows（Fs ） in taproot of Caragana korshinskii were measured continually with thermal dissipation probe（TDP） technique from April to October in 2008,and the environmental factors were recorded synchronously.The data of 30 sunny days were selected for analysis.The results showed that the forms of Fs exhibits a typical normal distribution with wide peak,which could be divided into 4 phase obviously,reflecting driven effects of meteorological factors and regulation effects of stomatal behavior.The Fs was driven by multiple factors jointly.The potential evapotranspiration（ET0 ）was closely correlated to Fs so as to be a comprehensive and compounded environmental variable.The coupling relationship between Fs and main environment factors varied diurnally.Fs had a liner relationship with solar radiation and ET0 at initiating and increasing stage of the flow after sunrise,which suggested that the solar radiation would be the driving mechanism to Fs and activation effects of photosynthesis.Fs showed a Sigmoidal-Hill function relationship with solar radiation and ET0 at the decreasing stage after the peak.The Fs relationships with vapour pressure deficit（VPD） was contrary to that with solar radiation and ET0 ,which implied that VPD could trigger stomatal regulation and control over-transpiration.Fs varied with main environment factors nearly simultaneously and no obvious time lags were found.Nocturnal sap flows were measured in many days of the growth season,and the average flow accounted for 3.83% of the total daily sap flows.The results approved the validation and superiority of the TDP technique for measuring sap flow of the whole tree in taproot of the shrubs.
出处
《林业科学》
EI
CAS
CSCD
北大核心
2010年第3期29-36,共8页
Scientia Silvae Sinicae
基金
中央级公益性科研院所基本科研业务费专项资金项目"半干旱区坡地典型植物篱复合系统构建技术"(200708)
国家"十一五"科技支撑项目(2006BAD03A0501
2006BAD03A1205)资助
关键词
热扩散技术
柠条锦鸡儿
根部液流
潜在蒸发散
环境因子
thermal dissipation probe（TDP）
Caragana korshinskii
sap flows in taproot
potential evapotranspiration（ET0）
environmental factors
