Widening of xylem conduits in a conifer tree depends on the longer time of cell expansion downwards along the stem.
Widening of xylem conduits in a conifer tree depends on the longer time of cell expansion downwards along the stem.
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DOI：
10.1093/jxb/err309
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发表时间：
2012-01
影响因子：
6.9
通讯作者：
Rossi S
中科院分区：
文献类型：
--
作者：
Anfodillo T;Deslauriers A;Menardi R;Tedoldi L;Petit G;Rossi S
维管的直径向茎基部增大。有人认为，当树木长高时，这种轮廓是一种有效的解剖特征，可以减少水力阻力。然而，控制植物细胞直径的机制尚不完全清楚。研究了细胞沿茎分化的时间。研究了一棵杉树（11.5 m高）的形成层活性和细胞分化，每隔4 d在茎部的9个不同高度（1 ~ 9 m）采集微样本。对8 ~ 12 μm厚的木材切片进行染色，在偏振光光镜下观察木质部细胞的分化。用甲酚紫醋酸酯检测细胞壁木质化。第一批增大的细胞几乎同时沿着树轴出现，这表明形成层的激活与高度无关。在离地面9 m处，木质部细胞的扩张期为7 d，在离地面6 m处为14 d，在离地面3 m处为19 d。相同高度下，木质部细胞的扩张期与管胞管腔面积呈正相关（r2=0.68, P < 0.01）。相比之下，早期木材的细胞壁厚度没有随高度变化的趋势。沿茎向下的导管管腔面积与分化细胞处于扩张期的时间呈线性关系。然而，这种远距离模式分化的感应信号仍有待确定。
The diameter of vascular conduits increases towards the stem base. It has been suggested that this profile is an efficient anatomical feature for reducing the hydraulic resistance when trees grow taller. However, the mechanism that controls the cell diameter along the plant is not fully understood. The timing of cell differentiation along the stem was investigated. Cambial activity and cell differentiation were investigated in a Picea abies tree (11.5 m in height) collecting microsamples at nine different heights (from 1 to 9 m) along the stem with a 4 d time interval. Wood sections (8–12 μm thick) were stained and observed under a light microscope with polarized light to differentiate the developing xylem cells. Cell wall lignification was detected using cresyl violet acetate. The first enlarging cells appeared almost simultaneously along the tree axis indicating that cambium activation is not height-dependent. A significant increase in the duration of the cell expansion phase was observed towards the tree base: at 9 m from the ground, xylem cells expanded for 7 d, at 6 m for 14 d, and at 3 m for 19 d. The duration of the expansion phase is positively correlated with the lumen area of the tracheids (r2=0.68, P < 0.01) at the same height. By contrast, thickness of the cell wall of the earlywood did not show any trend with height. The lumen area of the conduits down the stem appeared linearly dependent on time during which differentiating cells remained in the expansion phase. However, the inductive signal of such long-distance patterned differentiation remains to be identified.
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DOI：
10.1051/forest:19890563
发表时间：
1989-01-01
期刊：
ANNALES DES SCIENCES FORESTIERES
影响因子：
--
作者：
ALONI, R
通讯作者：
ALONI, R
影响因子：
4
作者：
Goodine, G. K.;Lavigne, M. B.;Krasowski, M. J.
通讯作者：
Krasowski, M. J.
影响因子：
1.9
作者：
Rossi, S;Anfodillo, T;Menardi, R
通讯作者：
Menardi, R
影响因子：
2.9
作者：
ALONI, R;ZIMMERMANN, MH
通讯作者：
ZIMMERMANN, MH
影响因子：
2.2
作者：
Deslauriers, A;Morin, H;Begin, Y
通讯作者：
Begin, Y