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在温室条件下 ,控制不同干旱梯度 ,用改良的冲洗法测定了 4年生油松、侧柏苗木的水力结构参数 .研究表明 ,随着小枝水势的降低 ,水力结构各参数随茎段功能木质部直径的变化可以用不同的方程来模拟 ;油松苗木在轻度水分胁迫下导水率剧烈丧失 ,侧柏苗木在中度水分胁迫下导水率剧烈丧失 .在落叶之前 ,相同直径油松和侧柏苗木枝条的胡伯尔值随小枝水势的变化很小 ,说明苗木水分胁迫主要源于木质部空穴和栓塞 .油松、侧柏苗木在干旱过程中水力结构的不同变化趋势 ,有助于人们从新的角度认识树木的水分生理特性
Under different greenhouse conditions, the different drought gradients were controlled, and the hydraulic parameters of Pinus tabulaeformis and Platycladus orientalis were determined by the improved flushing method.The results showed that with the decrease of branchlet water potential, the parameters of hydraulic structure varied with the diameter of stem xylem Can be simulated by different equations; the hydraulic conductivity of Pinus tabulaeformis seedlings under severe water stress is drastically lost, and the water conductivity of Platycladus orientalis seedlings under severe water stress is greatly lost. Before the deciduous leaves, The change of the Humber value of branch seedlings with the branch water potential is very small, indicating that the seedling water stress is mainly caused by the cavitation and embolism of the xylem.The different tendency of the hydraulic structure of Pinus tabulaeformis and Platycladus orientalis seedling during the drought helps people Recognize the water physiological characteristics of trees from a new perspective