Question

Bolting in some plants is induced by artificial treatment with which of the following plant hormones?
A) Ethylene
B) Auxin
C) Abscisic acid
D) Gibberellins

Answer 1

Hint: Bolting is a phenomenon by which flowering stems are often produced in the horticultural or agricultural crops before it is harvested. Bolting occurs as an attempt to produce seeds under stress conditions. This is often accompanied by plant hormone, also called phytohormones.

Complete answer:
Bolting is often referred to as the survival mechanism of a plant under stressed conditions. In this process the flowering stems are elongated for production of seeds before the harvest of the crop. It aids in increasing the reproduction of the plant. Basil, lettuce, onion, etc are some of the examples of bolted crops. The induction of bolting is carried out by artificially treating crops with plant hormone gibberellins. This results in elongation of internodes enormously thus elongating the stems in plants under normal circumstances.

So the correct answer is option “D” that is the bolting in some plants is induced by artificial treatment with plant hormones gibberellins.

Note: Various factors like the dominance of elevated temperatures at particular stages of the growth cycle of plants, variation in length of day and occurrence of stresses such as low mineral and water supply, often results in bolting of a plant. It occurs just before flowering and reproduction of a plant. It is naturally induced by photoperiods and suitable temperatures. Bolting can be artificially induced by plant hormone gibberellins. These plant hormone gibberellins are present naturally in the plants but can also be induced exogenously. These gibberellins increase the height of intermodal regions present in the stem.