Question

Which plant hormone promotes cell division?
A. Gibberellins
B. Cytokinin
C. Ethylene
D. Auxins

Answer 1

Cell division or cytokinesis is an important mechanism in plants. It allows longitudinal growth and plants part differentiation in plants. The plant hormones are chemical messengers that stimulate particular plant cells to undergo a specific mechanism. Examples of cell division causing plant hormones are kinetin and benzyl-aminopurine.

Complete answer: Plant growth hormones are a class of chemicals that is responsible for stimulating various kinds of mechanisms in plants for their growth and development. Elongation of stem, root, senescence, and blooming of flowers, seed germination, etc. are all caused and controlled by plant growth hormones.
Let us understand the function of each of the given plant hormones to know which of them stimulates cell division.
-Gibberellins are involved in regulating various developmental processes of plants. Stem elongation, seed dormancy, and germinations, flowering, etc. are all controlled by gibberellins. These are one of the longest classes of plant hormones. Gibberellins are also known to provide nutrition to germinating seeds when no proper stem or root is present.
-Cytokinin as their name suggests helps in cytokinesis. Cytokinesis or cell division is the process of cell proliferation and differentiation. Apical dominance, axillary bud growth, senescence of flowers, etc. are functions of cytokinin. It plays an important role in primary plant growth as it affects the cell division rate in the plant. Benzyl-aminopurine and kinetin are examples of cytokinins.
-Ethylene is also an important class of plant hormones. It is a gaseous state hormone that helps in fruit ripening and rotting. It is used by farmers to regulate fruit storage and harvesting.
-Auxins play a key role in maintaining behavioral processes in the plant life cycle. These are the most essential hormones in plant development processes. Auxins work at cellular, tissue, and organ level maintaining whole-plant growth.

Note: Cytokinins are used by farmers to promote plant growth and increase yield. Also, cytokinins are discovered to play an important role in plant pathogenesis. They provide resistance to various bacterial strains. Moreover, cytokinins are used in the context of biological control of plant diseases.