Question

Indole-3 acetic acid, called as auxin was first isolated from ______.

Options

• Human urine

• Corn germ oil

• Fusarium

• Rhizopus

Answer 1

Indole-3 acetic acid, called as auxin was first isolated from human urine.

Explanation:

Indole-3-acetic acid (IAA), the principal naturally occurring plant growth hormone of the auxin class, was surprisingly first isolated chemically by Kögl and Haagen-Smit from human urine. They extracted a compound possessing high plant growth activity and termed it heteroauxin, which was later structurally identified as IAA. Only after this breakthrough discovery did scientists successfully isolate the hormone directly from fungi and higher plant sources like corn germ oil.