Question

Gibberellin was first extracted from ..................
A. Gibberella fujikuroi
B. Algae
C. Bacteria
D. Roots of higher plants

Answer 1

Hint:-Gibberellin is a type of plant hormone which is found in angiosperms, gymnosperms, mosses, and algae. It is also present in some fungi. In plants, gibberellins are found in the form of gibberellic acid.

Complete answer:
Gibberellins regulate growth and many important developmental processes in plants which include seed germination, stem elongation, dormancy, flowering, flower development, maturation of pollen, leaf, and fruit senescence. They stimulate elongation of the shoot even in mature regions of trees & shrubs.
In 1926, Elichi Kurosawa, a Japanese botanist, while studying Bakanae, a foolish seedling disease in rice observed abnormal elongation of rice seedlings which were infected by the pathogenic fungi, Gibberella fujikuroi. He concluded that the fungi had secreted a chemical that was responsible for the severe stem overgrowth. Later in the 1930s, gibberellic acid was first extracted by Teijiro Yabuta and Sumuki from the same fungal species, Gibberella fujikuroi. Thus, Yabuta named the isolated hormone Gibberellin.
Thus, the right option is A.

Additional information:-
Gibberellins belong to the family of tetracyclic diterpenoid. Diterpenoid is the basic structural unit around which different functional groups are attached. This allows it to form different forms of gibberellin. Presently, more than 100 unique types of gibberellins have been identified. This makes gibberellins the largest hormone group.

Note:- Gibberellin in conjunction with other plant hormones produces effects on plant growth and other major functions. They are mostly concentrated at the roots. The first identified gibberellin was Gibberellin A1. The commercial production of gibberellin is done by culturing fungi that can produce gibberellin in a greater amount than plant sources.