Biología - 9 - Acetabularia
Each Acetabularia cell is composed of three segments: the "foot" or base which contains the nucleus, the "stalk," and the "cap." Hämmerling exchanged caps between individuals from two species, A. mediterranea and A. crenulata. A. mediterranea has a smooth, disc shaped cap, while A. crenulata has a branched, flower-like cap.
After the exchange, each transplanted cap gradually changed from its original form to the form typical for the species of the base it was now attached to. This showed that the nucleus controlled the form of the cap.
In another experiment, Hämmerling inserted a nucleus from one species of Acetabularia into an intact Acetabularia of a different species. The Acetabularia then produced a hybrid cap with characteristics of both species. This showed that both nuclei influenced the form of the cap.
Hammerling's results showed that the nucleus of a cell contains the genetic information that directs cellular development.