Chapter 32-7. Regeneration and Transplantation of Hydra
Recommended post: 【Biology】 Chapter 32. Embryology
1. Regeneration and Transplantation of Hydra
1. Regeneration and Transplantation of Hydra
⑴ Hydra is a diploblastic animal.
⑵ When both the head and the foot are removed, a head forms from the head-side portion of the body column, and a foot forms from the foot-side portion of the body column.
① Hydra regeneration exhibits polarity.
② This is because a head activator is secreted at the head tip (hypostome), establishing a concentration gradient from head to foot, while a foot activator is secreted at the foot tip (basal disc), establishing a gradient from foot to head.
⑶ In head formation induced by grafts, not only the graft itself but also the properties of the transplantation site are important.
① When tissue from the body column is grafted to a more basal (lower) region of the body column, a head forms at the grafted site.
② When tissue from the body column is grafted to a more apical (upper) region of the body column, a head fails to form at the grafted site.
○ This is due to a head inhibitor secreted from the head tip (hypostome).
Input: 2022.04.24 19:28