Question

Auxins are growth hormones capable of promoting cell elongation. They have been used in horticulture to promote growth, flowering and rooting. Explain the meaning of the
following terms related to auxins.

a.auxin precursors

b.anti-auxins

c.synthetic auxins

Answer 1

a. Auxin precursors:

The compounds which get converted into auxins in certain biosynthetic pathways are called as auxin precursors. Tryptophan is an aromatic amino acid and it takes part in the formation of auxins. Hence, it is an auxin precursor.

b. Anti-auxins:

Compounds which inhibit the action of auxins or interfere with their transport are called anti-auxins. For example, TIBA (2,3,5-triiodobenzoic acid) and PCIB (p-Chlorophenoxyisobutyric acid) act as anti-auxins.

c. Synthetic auxins:

Auxins can be synthesised artificially. Artificially synthesised chemicals that have auxin-like properties and activities are called synthetic auxins. For example, naphthalene acetic acid, 2,4-dichlorophenoxyacetic acid and 2,4,5-trichlorophenoxyacetic acid are examples for synthetic auxins.