Gibberellin was discovered froma)Bacteriab)Roots of higher plantsc)Fungid)AlgaeCorrect answer is option 'C'. Can you explain this answer?

Question

Answer

Gibberelin was 1st discovered in japan by kurusowa.He observed from his field that some of rice seedlings had grown much taller than others. on further observations he found that such taller rice plants had shown unusual internodal elongation.The internal elongation is known as bakane or foolish seedling disease of rice.Later it was discovered that elongation was due to a action of substance produced by fungusGibberella fujikuroi.The substance was successfully isolated from the fungus and it was named as gibberelic acid.

Answer

Gibberellins are plant hormones that regulate growth and influence various developmental processes, including stem elongation, germination, dormancy, flowering, sex expression, enzyme induction and leaf and fruit senescence. Gibberellin was first recognized in 1926 by a Japanese scientist, Elichi Kurosawa studying bakane, the 'foolish seedling disease' in rice. It was first isolated in 1935 by Teijiro Yabuta and Sumuki from fungal strains provided by Kurosawa from Gibberella fujikuroi. Yabuta named the isolate as gibberellin.
As Gibberella fujikuroi is a fungus, here answer is option C....

Answer

Gibberellin was discovered from fungi.

Discovery of Gibberellin:
Gibberellin is a plant hormone that was first discovered in Japan in the 1930s. It was isolated from the fungus Gibberella fujikuroi, which was causing abnormal elongation of rice plants. The discovery of gibberellin revolutionized the field of plant physiology and has since been extensively studied for its various effects on plant growth and development.

Gibberella fujikuroi:
Gibberella fujikuroi is a filamentous fungus that infects various plants, including rice. When it infects rice plants, it causes a disease known as 'foolish seedling disease' or 'bakanae disease.' This disease is characterized by the excessive elongation of infected rice plants, which grow taller and thinner than healthy plants. The fungus produces a compound that was later identified as gibberellin, which is responsible for the abnormal growth of infected plants.

Identification and Isolation:
The identification and isolation of gibberellin from Gibberella fujikuroi involved a series of experiments. Researchers initially observed that the fungus produced a substance that caused elongation of rice seedlings even in the absence of light. They hypothesized that this substance might be responsible for the abnormal growth observed in infected plants.

To isolate the compound, the researchers cultured the fungus and extracted the culture filtrate. They then fractionated the filtrate using various techniques such as solvent extraction, adsorption chromatography, and crystallization. Through these purification steps, they obtained a pure compound, which they named gibberellin.

Effects of Gibberellin:
Gibberellin has diverse effects on plant growth and development. Some of its key effects include:

1. Stem elongation: Gibberellin promotes stem elongation by stimulating cell division and elongation in the internodes of plants.

2. Seed germination: Gibberellin breaks seed dormancy and promotes seed germination by enhancing the production of hydrolytic enzymes.

3. Flowering: Gibberellin plays a role in flowering regulation, influencing the transition from vegetative growth to reproductive growth.

4. Fruit development: Gibberellin promotes fruit growth and development by stimulating cell division and enlargement.

5. Leaf expansion: Gibberellin stimulates leaf expansion, leading to increased leaf size.

6. Bolting in biennial plants: Gibberellin triggers the rapid growth and elongation of the flowering stem in biennial plants.

Conclusion:
In conclusion, gibberellin was discovered from the fungus Gibberella fujikuroi. This discovery highlighted the importance of fungi in the production of plant hormones and opened up new avenues of research in the field of plant physiology. Gibberellin has since been extensively studied for its various effects on plant growth and development.

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