论文部分内容阅读
树干储存水在协调叶片水分和碳平衡、维持树木水分收支平衡中起着重要作用。以无孔材红松(Pinus koraiensis)、散孔材山杨(Populus davidiana)和环孔材蒙古栎(Quercus mongolica)为对象,于2010年8月中旬至9月末(生长季后期)测定其冠基和干基树干液流通量以及树干储存水的日变化过程,量化分析树干储存水对日蒸腾量的贡献及其生物影响因子。结果表明:冠基的液流比干基启动得早,而且两者在一天中存在显著的时滞。树干储存水的日进程总体上可分为:完全释放、以释放为主补充为辅、以补充为主释放为辅、饱和稳定等4个阶段,但每个阶段的持续时间和变化格局随树种而变。红松的树干储存水在一天内表现出两个释放-补充周期,而两种阔叶树种均只经历了一次释放-补充过程。在测定时段内红松、山杨、蒙古栎标准化到平均木(边材体积为0.29 m3)的树干储存水释放量分别为:(3.4±1.5)、(2.4±0.6)和(1.5±0.4)kg.d–1,分别占日蒸腾量的18.9%、17.1%和8.8%。树干储存水释放量与日蒸腾量呈显著的指数函数关系,而与干基的边材面积和树高呈正相关关系。该研究突显了树木大小(树高和边材面积)和材性特征对树干储存水释放量及其对蒸腾量贡献的重要影响。
Trunk storage of water plays an important role in coordinating the water and carbon balance of the leaves and maintaining the water balance of trees. Pinus koraiensis, Populus davidiana and Quercus mongolica were taken as test objects and the crown was measured from mid August to the end of September 2010 (the later growing season) Basal and stem-based dry fl ux flux and diurnal change of trunk storage water, quantitatively analyzed the contribution of trunk storage water to daily transpiration and its biological influence factors. The results show that crown-based fluid flow is earlier than dry-based, and there is a significant time lag between the two during the day. The daily process of water storage in trunk can be divided into four stages: complete release, supplemented by release supplementation, supplemented by main release supplementation, saturation and stability, but the duration and variation pattern of each stage varies with tree species And change. Korean pine trunk water storage showed two release-replenishment cycles in one day, whereas both broadleaf species experienced only one release-replenishment process. During the period of measurement, the release of trunk storage water standardized to average wood (sapwood volume 0.29 m3) was (3.4 ± 1.5), (2.4 ± 0.6) and (1.5 ± 0.4) kg.d-1, accounting for 18.9%, 17.1% and 8.8% of the daily transpiration respectively. There was a significant exponential relationship between water released from trunk storage and daily evapotranspiration, but positively correlated with the sapwood area and tree height. This study highlights the significant impact of tree size (tree height and sapwood area) and wood properties on trunk water storage capacity and its contribution to transpiration.