为研究沙柳蒸腾规律及其与气象要素的关系, 采用包裹式茎流计测量沙柳全叶期至落叶期液流速率, 并分析 了沙柳蒸腾与气象要素的关系。研究结果表明: 沙柳枝条液流速率与其直径呈正相关关系; 沙柳液流在早7 时开 始, 10 时至15 时处于高值, 16 时后急剧减少, 至夜间21 时后降至最低( 接近0) ; 沙柳液流速率具有典型的季节性特 征, 且受气象要素影响显著, 其受影响强烈程度的大小顺序为: 饱和水汽压差> 太阳辐射> 大气温度> 相对湿度> 风速; 另外, 参考蒸散发量和液流速率呈显著线性关系, 随着潜在蒸散发的增加, 沙柳蒸腾也呈增加趋势。

In or der t o investig ate the r elationship between the tr anspir ation of Salix psammophila and meteo ro log ical facto rs, packaged sap flow gauge w as used to measur e the sap flow v elo cities in the full leaf season and defo liation seaso n. The r esults show ed that ( 1) the sap flow v elo city of Sa lix psammophila branch has a positive corr elation w ith br anch diameter ; ( 2) sap flow velo city incr eases gr adually fr om 7 am in the mor ning , r eaches a peak between 10 am in the mo rning and 3 pm in the aft ernoon, then decreases g radually from 4 pm in the aft ernoon to the low est value ( near zero) aft er 9 pm at night; ( 3) sap flow velo city of Salix psammo phila has an obv iously seaso na l v ariat ion w ith the maximum value in July while the minimum in Nov ember ; ( 4) met eo ro lo gical facto rs ar e the mo st significant factor s affecting the sap flow velo city o f Salix psammophila in the following or2 der: vapor pr essure deficit> sola r radiatio n> air tem per at ur e> relative humidity> w ind speed; and ( 5) there is a sig nificant ly linear relat ionship betw een sap f low velocity and refer ence evapotr anspir ation w ith a cor relat ion coefficient of R2 = 0. 77

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