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以我国北方地区１０种造林树种为研究对象，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。１０个树种木质部水势的季节变化趋势与栓塞程度的变化趋势相反，冬、春季低于夏、秋季。一般情况下，水势越高，木质部栓塞程度小，但３月虽水势较高，木质部栓塞程度仍很严重，对此作了讨论。
Ten species of afforestation tree species in the northern part of China were selected as the research object to continuously measure the changes of the annual xylem embolism and water potential in 12 months. The results showed that the seasonal changes of coniferous xylem in coniferous tree were not obvious, and the change range was very small. Even in winter, the branch xylem could maintain a relatively high water delivery capacity. In the broad-leaved winter, the xylem embolism in spring was greater than that in summer and autumn. The maximum embolization degree and the lowest water potential of most species occurred in January with the lowest temperature in winter, and the lowest embolism and highest water potential appeared in September with the highest precipitation in autumn. The seasonal trend of xylem water potential of 10 tree species was opposite to that of embolism degree. The winter and spring were lower than summer and autumn. Under normal circumstances, the higher the water potential, xylem embolism is small, but in March the higher the water potential, xylem embolism is still very serious, which was discussed.