Question

The natural plant hormones were first isolated from :

• A. Corn germoil and human urine
• B. Cotton fruits, spinach leaves and rice plants
• C. Human urine and rice seedlings
• D. Spinach leaves and fungus Gibberella

Answer 1

Answer: (A)

The first naturally occuring auxin was isolated by Kogl and Haagen-Smit (1931) from human urine. It was identified as auxin-a (auxentriolic acid). Later, in 1934 Kogl, Haagen-Smit and Erxleben obtained another auxin called auxin-b (auxenolonic acid) from corn germ oil (extracted from germinating corn seeds).