Question

In .............................., role of nucleus in morphology of plant was first discovered.

• A. Acetabularia
• B. Maize
• C. Pea
• D. Neurospora

Answer 1

The correct option is A Acetabularia

• Acetabularia were used in the early days of cell biology for some amazing experiments on nuclear transplantation and cellular development. About 75 years ago, Joachim Hmmerling discovered that he could cut the organism in half with impunity and that each half would regrow the alga.
• He also found that if he cut it again, the specimen that had come from the top half would wither away and not regenerate further, whereas the one from the bottom half did regrow even after many such surgeries. Is the reason that the bottom part has the nucleus? He answered the question by a direct experiment, based on the ability of the cut upper pieces to be grafted onto lower pieces with the nucleus. The grafts took and a new plant regenerated, cap and all.
• The two species Hmmerling chose differed in their cap morphology, one, A. crenulata, having a wavy-edged or crenulated cap, the other, A. mediterranea (now called A. acetabulum), a smooth one.
• The defining observation was that the regenerated plant had the morphological characteristic of the bottom part, which was the first conclusive demonstration that the nucleus controls development.
• To confirm this, he transplanted nuclei of one species into another and got a hybrid with characteristics of both species. So, role of nucleus in morphology of plant was first discovered in acetabularia and not in maize, pea and neurospora.