茎的皮层和髓部具很多大型的薄壁细胞。

There are lots of large parenchyma cells in the cortex and pith of the stem.

youdao

幼虫蛀食髓部及木质部，形成隧道，严重影响养分和水分的传导。

The larvae tunnel into the stems and interrupt the conduction of water and nutrients.

youdao

在下胚轴中、上部，髓部开始出现，初生木质部分化顺序为内始式；

At the upper and the middle part of hypocotyl, the pith appears, and the order of the primary xylem differentiation is endarch.

youdao