Question

For the first time, gibberellin was found in a/an ___________.

• A. autoclaved herring sperm DNA
• B. fungi
• C. coleoptile of canary grass
• D. human urine

Answer 1

The correct option is B fungi

For the first time gibberellin was found in fungi. E. Kurosawa was investigating the foolish seedling disease. He found that it was caused by a fungal pathogen Gibberella fujikuroi, these fungi were found to be producing the hormone gibberellin.

Kinetin was discovered from the autoclaved herring sperm DNA. It belongs to the cytokinin group, a type of plant growth regulator. It is a modified form of adenine. It does not occur naturally in plants. It mainly promotes cell division in plants.

The bending of the coleoptile of canary grass towards the light source was observed by Francis Darwin. He observed that the tip of the coleoptile was the site of transmittable influence that caused the bending of the entire coleoptile. Auxin was isolated by F.W. Went from tips of coleoptiles of oat seedlings.

But auxin for the first time was isolated from human urine. Auxin is a plant growth promoter that helps to promote apical dominance ( a phenomenon in which the growth of the main central stem of the plant is more as compared to the other stems), helps in initiation of flowering(e.g in pineapple), and can also be used as a weedicide(e.g 2,4-D)