histogen

1.See histogen theory;

参见histogentheory;

2.In roots, however, the concept is still applied, and in some angiosperm roots a fourth histogen zone is recognized, the calpytrogen, which gives rise to the root cap.

然而在根中，它还是适用的。在一些被子植物的根中，还发现种组织原，calpytrogen，与根冠发有。