Question

________ hormone is considered as a plant growth promoter as well as a plant growth inhibitor.

• A. Auxin
• B. Gibberellin
• C. Ethylene
• D. Cytokinin

Answer 1

The correct option is C Ethylene

Plant growth regulators are small, simple chemicals that control the growth and development of a plant. These are also termed phytohormones or plant hormones. Phytohormones are broadly divided into two categories:

1. Plant growth promoter: Such plant growth regulators that are involved in plant growth-promoting activities like cell division, flowering, etc. are called plant growth promoters. For example, cytokinin, auxin, gibberellin.

2. Plant growth inhibitor: The plant growth regulators that are involved in growth-inhibiting activities like dormancy (temporary inactive state of the cell), abscission (natural shedding of plant parts). For example, abscisic acid.

Ethylene is a plant growth promoter as well as a plant growth inhibitor. Ethylene is produced by tissues of plants undergoing senescence and ripening of fruits in the form of gas. It helps in the growth of root hairs and elongation of internodes in deep water rice plants.