Question

In plants, which of the following hormones is primarily responsible for promoting cell elongation in stems?

• A. Cytokinin
• B. Gibberellin
• C. Abscisic acid
• D. Ethylene

Hint:

To identify the role of plant hormones, associate gibberellins with stem elongation and growth, cytokinins with cell division, abscisic acid with stress responses, and ethylene with ripening and senescence.

Answer 1

The Correct Option is B

Plant hormones regulate various growth and developmental processes. Among the given options, gibberellin is primarily responsible for promoting cell elongation in stems, leading to stem elongation and overall plant growth. Gibberellins stimulate cell division and elongation, particularly in the internodes of stems, and are often used to increase stem length in plants like dwarf varieties.
The roles of the other hormones are:
- Cytokinin: Promotes cell division and delays senescence but is not primarily responsible for cell elongation.
- Abscisic acid: Inhibits growth and promotes dormancy and stress responses, such as closing stomata during water deficiency.
- Ethylene: Promotes fruit ripening and senescence, and can inhibit elongation in some cases.
Thus, the hormone primarily responsible for promoting cell elongation in stems is gibberellin.