Question

Which of the following plant hormones promotes cell division?
A) Abscisic acid
B) Auxin
C) Gibberellins
D) Cytokinin

Answer 1

Hint: Plant hormones are also known as phytohormones. These are formed inside plants in very low concentrations. These help in regulation of plant growth and development from early embryonic stages.

Complete step-by-step answer:
A variety of hormones is produced by plants. These hormones are therefore also known as phytohormones. They include Auxin, gibberellins, abscisic acid, cytokinin, etc.
Auxins are the hormones promoting elongation of cells under the influence of gravity (gravitropism) or light (phototropism). Auxins are responsible for flowering and apical dominance (which inhibit the formation of lateral buds).
Gibberellins are plant hormones synthesized in the young leaves, apical meristems of roots and shoots, and seed embryos. These hormones stimulate elongation of shoot, maturation of flowers and seed germination. Gibberellins play a major role in breaking seed dormancy.
Abscisic acid (ABA) is also known as an inhibitory hormone. It is responsible for stomatal closing and seed dormancy. It is also known to inhibit the actions of other hormones.
Cytokinin, as the name suggests, promotes cytokinesis that is division of cells. Its role was first reported when liquid endosperm of coconut was added to the culture of developing plant embryos. This addition stimulated the growth of the concerned embryos. Majority of cytokinins are found at the site of cell division in growing tissues, such as embryos, roots, and fruits. Senescence in leaf tissues is known to be delayed by cytokinins. It stimulates meristem differentiation into roots and shoots by promoting mitosis.

Therefore, the correct answer is option “D” that is cytokinin is the plant hormone that promotes cell division.

Note: Plant hormones are organic substances that provide signals for regulating plant growth and development. Auxin, cytokinin, ethylene, abscisic acid, gibberellins are some of the major plant hormones. Cytokinins in association with other hormones have a high impact on plant development processes.