exodermis

The exodermis cell wall possesses the highest auto-fluorescent intensity whereas that of velamen the lowest.

自发荧光强度以外皮层最高，最低。

Exodermis An outermost layer of thickened or suberized cortical cells that sometimes replaces the epidermal layer in the older parts of roots if the epidermal cells have died.

外皮层：薄或木栓化皮层细胞最外层。如果较老部分表皮细胞死，常取而代之。