The central vascular strand goes through major part of embryo, and in the areas to where the central vascular strand can not extend, there exists a regional conducting system.

中央维管网贯穿胚体，其盲端区常出现不能与之连通的局部输导组织。

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Procambium (procambium strand) The layer of cells that gives rise to the vascular tissue.

原形成层（原形成层束）：形成维管组织的一层细胞。

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