关键词: 土壤水势, 植物水分状况, 茎直径微变化, 气象因子

Abstract:

In this paper, the pattern of dynamic change of Jujube’s stem diameter and its influencing factors (the soil moisture and meteorology factors)were studied under two soil water potential gradients (T1: -15~ -25 kPa,equivalent to field capacity 65%-70%; T2: -45--55 kPa,equivalent to field capacity 50%-55%). The factors influencing the model prediction were analyzed through establishing regression model between maximum daily trunk shrinkage (MDS) and reference crop evapotranspiration (ET₀), daily mean vapor pressure deficit (VPD), daily temperature difference (DTD) and air water potential (Ψ_a). The results showed that: 1) The fluctuation of soil water potential of T2 was greater than that of T1. The values of maximum daily trunk shrinkage (MDS) and trunk daily growth (DG) of T2 were greater than that of T1, while the values of maximum trunk diameter (MXTD) and minimum trunk diameter (MNTD) were smaller than that of T1. 2) The linear correlation coefficients between MDS and air evaporation strength index and temperature index were much greater under both soil water potential gradients, while the linear correlation coefficient between MDS and meteorology factors in T1 was greater than that of T2. (3) Extreme weather conditions caused sharp change (extreme value) in stem diameter and influenced the prediction accuracy of MDS model during the experimental period.

Key words: ziziphus jujuba soil water potential, water status of plant, stem diameter micro-variation, meteorological factors