几种木本植物木质部栓塞的季节变化

Seasonal Variation of Xylem Embolism in Some Woody Plants

以我国北方地区１０种造林树种研究对象，连续测定其一年生枝木质部栓塞及水势在１２个月中的变化情况。结果表明，针叶树木质部栓塞的季节变化不明显，变化幅度很小，即使在冬季其枝条木质部仍能维持相对较高的输水能力。阔叶树冬、春季木质部栓塞程度大于夏、秋季，多数树种最大栓塞程度和最低水势出现在冬季气温最低的１月，最小栓塞程度和最高的水势出现在秋季降水最多的９月。

Experiments were conducted on 1 year old twigs excised from 10 tree species growing in the arboretum of Northwest Forestry University. Xylem embolism was tested by the “flushing method” and water potential was monitored using a pressure chamber. The results showed that seasonal variation of xylem embolism in conifers was not distinct, even in winter, higher hydraulic conductivity could be observed, but xylem embolism in twigs of the 7 deciduous species, was higher in winter and early spring than that in summer and autumn. The highest xylem embolism occurred in winter and the lowest in autumn. Three was an inverse relationship between xylem water pontential and xylem embolism, the lower the water potential, the higher the xylem embolism, but in March, even water ponential was higher, xylem embolism was still serious, this was also discussed in the paper.