Seasonal Changes in the Distribution of Water in the Outer Growth Rings of Fraxinus Mandshurica Var. Japonica: A Study By Cryo-Scanning Electron Microscopy
Seasonal Changes in the Distribution of Water in the Outer Growth Rings of Fraxinus Mandshurica Var. Japonica: A Study By Cryo-Scanning Electron Microscopy
复制标题
水曲柳外生长轮水分分布的季节变化。
DOI：
10.1163/22941932-90001439
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发表时间：
1996
期刊：
影响因子：
1.9
通讯作者：
S. Fujikawa
中科院分区：
文献类型：
--
作者：
Yasuhiro Utsumi;Y. Sano;J. Ohtani;S. Fujikawa
水曲柳外生长轮中水分分布的季节性变化。利用冷冻扫描电子显微镜观察了水曲柳活体树干中水分的冻结固定。在5月中旬至7月下旬的生长季节，木质部的形成过程比较稳定，新生木质部分子的细胞腔都充满了水。从8月到10月，水分从当年木质部的木纤维的管腔中损失。从木材纤维的水分损失开始于8月在早材的初始区，并向形成层区进展。到11月，水已经从当年早材船只的管腔中消失，水重新出现在当年早材船只周围的早材纤维管腔中。研究结果表明，当年早材船在10月至11月期间发生了空腔。
Seasonal changes in the distribution of water in the outer growth rings of Fraxinus mandshurica var.japonica were visualised by cryo-scanning electron microscopy using samples in which water was freeze-fixed in the living trunk . During the growing season from mid-May to late-July when formation ofxylem progressed steadily, all cell lumina of the newly forming xylem elements were filled with water. From August to October, water was lost from the lumina of wood fibres in the current-year xylem. Loss of water from wood fibres began in August at the initial zone of the earlywood, and progressed toward the cambial zone. By November, water had disappeared from the lumina of current-year earlywood vessels, and water reappeared in the lumina of earlywood fibres around the currentyear earlywood vessels. Our results indicate that cavitation in lumina of current-year earlywood vessels occurred during the period from October to November.