八个绿化树种水分状况与水力结构的季节变化

为了解绿化树种的水分状况和水力结构特征的季节变化规律，该文应用改良的冲洗法，选取油松、侧柏等8个树种为研究对象，测定枝条水势和水力结构的变化.结果表明:8个树种水势的日变化在不同月份皆呈现“单峰”趋势；导水率和比导率的逐月变化幅度反映了木质部栓塞脆弱性为国槐、女贞、旱柳、黄栌油松、侧柏、沙地柏小叶黄杨;叶比导率的变化幅度与比导率的变化趋势一致,进入10月份国槐和黄栌表现出严重落叶现象时,它们的叶比导率值并没有明显降低,说明植物的落叶可能对保持存留叶片的水分状况有重要作用. 作为CAM植物的小叶黄杨在水势上一直保持低值,并且在水力结构的各个参数分析上均有其特殊性,这种情况的出现很可能与其不同的光合途径有关. 

Water conditions and seasonal changes of hydraulic architecture in eight greenery tree species.

The improved flushing method was used, and Pinus tabulaeformis, Platycladus orientalis and other 6 tree species were selected to measure the water potential and hydraulic architecture parameters of twigs, in order to study the water conditions and seasonal changes of the hydraulic architecture of these 8 greenery tree species. Results showed that the water potential of the 8 tree species exhibited an obvious “single peak” trend; monthly change range of Kh and Ks which reflected the vulnerability of xylem embolism showed the following order: Sophora japonica, Ligustrum lucidum,Salix matsudana and Cotinus coggria>P. tabulaeformis,P. orientalis and Sabina vulgaris> Buxus microphylla; The change range of LSC accorded to that of Ks, and the LSC of S. japonica and C. coggria had no obvious decline when their leaves fell after October, which indicated that this strategy of plants was likely to be important to the water condition of the reserved leaves. As a CAM plant the water potential of B.microphylla kept a lower level, and its hydraulic architecture parameters were different from other tree species, which might be related to its different photosynthestic paths.