The secondarythickening meristem originated from the parenchyma cells, which were located the outside of the atactostele.
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。
2
Structural roots: large roots that have undergone considerable secondarythickening and provide mechanical support to woody plants and trees.
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。
3
Many vessel numbers, small pore, libriform fibres (mechanical tissue)and obvious secondarythickening of xylem tissue are the features of adaptation to the environment.