Kinetics of tracheid development explain conifer tree-ring structure
Kinetics of tracheid development explain conifer tree-ring structure
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DOI：
10.1111/nph.12871
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发表时间：
2014-09-01
期刊：
影响因子：
9.4
通讯作者：
Fournier, Meriem
中科院分区：
文献类型：
--
作者：
Cuny, Henri E.;Rathgeber, Cyrille B. K.;Fournier, Meriem
针叶树的年轮通常由轻早木的大的薄壁细胞和致密晚木的窄的厚壁细胞组成。然而，木材形成过程和相关动力学如何产生这种典型模式仍然知之甚少。我们对法国3种针叶树的45棵树进行了为期3年的树木年轮形成监测。数据用于模拟细胞发育动力学，并归因于细胞扩大和细胞壁沉积的持续时间和速率对树轮结构的相对重要性。细胞增大持续时间对细胞直径沿年轮变化的贡献率为75%。值得注意的是，沿着环，每个细胞的壁材数量是相当恒定的。因此，与普遍的看法相反，细胞壁厚度的变化主要不是归因于壁沉积的持续时间和速率（33%），而是归因于细胞大小的变化（67%）。细胞增大持续时间是细胞大小和壁厚的主要驱动因素，对木材密度沿年轮变化的贡献率为56%。这个机制框架现在形成了揭示环境压力如何触发偏离正常树轮结构的基础（例如假环）。
Conifer tree rings are generally composed of large, thin-walled cells of light earlywood followed by narrow, thick-walled cells of dense latewood. Yet, how wood formation processes and the associated kinetics create this typical pattern remains poorly understood.We monitored tree-ring formation weekly over 3 yr in 45 trees of three conifer species in France. Data were used to model cell development kinetics, and to attribute the relative importance of the duration and rate of cell enlargement and cell wall deposition on tree-ring structure.Cell enlargement duration contributed to 75% of changes in cell diameter along the tree rings. Remarkably, the amount of wall material per cell was quite constant along the rings. Consequently, and in contrast with widespread belief, changes in cell wall thickness were not principally attributed to the duration and rate of wall deposition (33%), but rather to the changes in cell size (67%). Cell enlargement duration, as the main driver of cell size and wall thickness, contributed to 56% of wood density variation along the rings.This mechanistic framework now forms the basis for unraveling how environmental stresses trigger deviations (e. g. false rings) from the normal tree-ring structure.