J. Hammerling | Highlight Importance of Nucleus in his Experiments

 J. Hammerling

In 1934, Hammerling showed that the nucleus is the only controller of the cell. The nucleus controls all the activity of the cell and determines the character of the cell and so the character of an individual. The nucleus also carries the hereditary material of the cell. 

He proves this with his experiment on the largest unicellular algae. This alga was Acetabularia, a green alga. This green alga was about 10cm long in size.

He used two specimens of Acetabularia, which are: 

1. Acetabularia Crenulata  
2. Acetabularia Mediterranea

 These two specimens have different shapes. We can divide Acetabularia into three parts:

1.  Caps
2.  Stalk
3.  Base

J. Hammerling highlights the Importance of the Nucleus in his Experiments. 

• The caps of Acetabularia Mediterranea are umbrella-like in shape because they are very closely attached.
• The caps of Acetabularia Crenulata are loosely attached and form a loose structure of it.
• The nucleus is present in the base of both specimens.

Hammerling performs two experiments to prove that the nucleus controls the characters of the cell.

First Experiment.

•  Firstly Hammerling cuts the Acetabularia into three parts:

1. Caps
2. Stalk
3. Base

• He took three culture medium plates and placed all three parts (i.e. cap, stalk, and base) of Acetabularia in three cultural plates.
• He noticed after some time that caps and stalks were going to degenerate in culture plates but only the base showed some regeneration and formed new specimens. 

 

Second experiment.

• He takes two different specimens of Acetabularia.

1.  Acetabularia medetarranae
2.  Acetabularia crenulata.

• He cut both of the specimens into three parts I,e cap, stalk, and base.
• He then placed them on different cultural plates. 
• Then he takes out the nucleus of both specimens. 
• Then he places the nucleus of Medetarranae inside the Crenulata. And the nucleus of Crenulata inside the Medetarranae. In this way, he interchanges the nucleus of both specimens.
• He observed that the characters of both specimens changed.
• Crunulata started to behave like Medetarranae and Medetarranae started to behave like Crunulata.
• Crunulata developed a cap around it that was very similar to the cap of Medtarranae. 
• In the same way, the Medetarranae developed a cap that was similar to the cap of Crunulata.

Conclusion.

• It was confirmed from his experiment that the nucleus is the only one that controls the characteristics of cells.
• He also proves that the nucleus carries the hereditary material of the cell.
• He called the nucleus the brain of the cell because of its controlling ability.