从树木水力结构特征探讨植物耐旱性

于 2 0 0 1年 8月下旬在北京林业大学校园内选取油松、元宝枫等 10个树种为研究对象 ,测定 1年生枝条的水势和水力结构参数的昼夜变化 .结果表明 ,1年生枝条水势与水力结构参数的昼夜变化趋势呈明显的“单峰型”变化 .分别建立了水势与导水率、比导率、叶比导率关系的数学模型 :y =axb 和y =ax2 +bx +c ,探讨了模型中各参数的生理生态学意义 ,并比较了各供试树种木质部栓塞脆弱性的大小 ,依次如下 :刺槐 >皂荚 >元宝枫 >山桃 >红瑞木 >侧柏>雪松 >白皮松 >油松 >迎春 .木质部输水效率及空穴和栓塞化程度的大小 ,依次如下 :环孔材树种 >散孔材树种 >无孔材树种 .这说明植物输水结构的有效性和安全性不可完全兼得 .

Discussion on drought resistance through hydraulic architecture of trees

Pinus tabulaeformis, Acer truncatum and the other eight tree species were selected on the campus of the Beijing Forestry University to measure the hydraulic architecture parameters and water potential of one\|year\|old twigs. It was shown that day and night changes of water potential and hydraulic architecture parameters appeared to be obviously convex trend. The relationship models between water potential and hydraulic conductivity, special conductivity and leaf special conductivity were respectively established, which were simulated by equations y=ax b and y=ax 2+bx+c, through which the parameters, physiological meanings were discussed. Analysis showed that the embolism vulnerability of ten tree species was Robin pseudoacaia> Gleditsia sinensis> Acer truncatum> Prunus davidiana> Cornus alba> Platycladus orientalis> Cedrus deodara> Pinus bungeana> Pinus tabulaeformis> Jasminum nudiflorum, and that xylem water transport efficiency and embolism of the species were ring\|porous species>diffuse\|porous species>none\|porous species. It was clear that the plants hydraulic architecture effectiveness and security were not entirely available at the same time.