Yasuda Yuko, Utsumi Yasuhiro, Tashiro Naoaki, Koga Shinya, Fukuda Kenji
Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, 6-10-1, Hakozaki, Higashi-ku, Fukuoka, 812-8581, Japan.
Graduate school of Agriculture, Kyushu University, 6-10-1, Hakozaki, Higashi-ku, Fukuoka, 812-8581, Japan.
J Plant Res. 2018 Mar;131(2):261-269. doi: 10.1007/s10265-017-0984-7. Epub 2017 Oct 23.
This study evaluated variation in the height at which absent rings and internodes were detected along stem of Abies sachalinensis trees grown under shade for 39 years. Eight sample trees planted in 1974 under a secondary forest in Japan were felled in 2013 and analyzed. A. sachalinensis is a monopodial species in which it is possible to measure annual apical growth using the distinct internodes. We applied microscopic analysis on 154 stem disks from the stem base to the top to evaluate the cessation of apical and radial growth caused by intensive shading. Cessation of apical stem growth for one or more years was found in 6 out of 8 sample trees. We termed this phenomenon as "absent internode". In addition, the absent growth rings were detected more frequently in the lower part of sample stems, and the number of absent rings at the stem base did not correspond with the number of absent internodes in the six trees. From cellular level observation, the five suppressed trees had no living cambial cells at the stem base but had living cells at the stem top. The cessation of the apical and radial growth did not occur synchronously but did occur independently under a shade environment in A. sachalinensis.
本研究评估了在林下生长39年的库页冷杉树干上检测到无节间和无年轮的高度变化。对1974年种植于日本次生林下的8棵样本树于2013年进行砍伐并分析。库页冷杉是单轴树种，利用明显的节间可以测量每年的顶端生长。我们对从茎基部到顶部的154个茎盘进行微观分析，以评估因强烈遮荫导致的顶端生长和径向生长的停止情况。在8棵样本树中有6棵发现顶端茎生长停止了一年或多年。我们将这种现象称为“无节间”。此外，在样本茎的下部更频繁地检测到无年轮情况，并且在6棵树中，茎基部无年轮的数量与无节间的数量并不对应。从细胞水平观察来看，5棵受抑制的树在茎基部没有活的形成层细胞，但在茎顶部有活细胞。在库页冷杉中，顶端生长和径向生长的停止并非同步发生，而是在遮荫环境下独立发生。
