次生加厚分生组织起源于正常的散生维管束中柱外侧的薄壁组织细胞。
The secondary thickening meristem originated from the parenchyma cells, which were located the outside of the atactostele.
结构性根源：大根和树木已经历了相当大的次生加厚，并提供机械支持木本植物。
Structural roots: large roots that have undergone considerable secondary thickening and provide mechanical support to woody plants and trees.
红树植物导管数量多、管孔小、机械组织为韧型纤维，薄壁组织次生加厚明显是适应环境的特征。
Many vessel numbers, small pore, libriform fibres (mechanical tissue)and obvious secondary thickening of xylem tissue are the features of adaptation to the environment.
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