Question

Which hormone promotes cell division?

• A. Auxin
• B. Cytokinin
• C. ABA
• D. Ethylene Correct Answer: (B) Cytokinin

Hint:

This is one of the easiest etymological links to memorize in biology: Cytokinin drives Cytokinesis! Whenever a test question mentions rapid cell division, tissue culture proliferation, or breaking apical dominance to start fresh growth, look immediately for Cytokinin.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Cell division, or mitosis, is the fundamental biological driver behind tissue formation, organ growth, and structural development in all multicellular living organisms. In the plant kingdom, specialized chemical messengers trigger the various stages of the cell cycle—including DNA replication, spindle fiber assembly, and the final splitting of the cytoplasm (cytokinesis).

Step 2: Detailed Explanation:
Let's evaluate the primary functional roles of each phytohormone option: - (A) Auxin: Primarily promotes cell elongation, apical dominance, and root initiation, working alongside other hormones to guide tissue differentiation. - (B) Cytokinin: This class of hormones was discovered specifically during research into chemical agents that could trigger cell splitting in tissue cultures. The very name Cytokinin is derived directly from cytokinesis (the division of cytoplasm during mitosis). It actively coordinates with auxin to drive rapid cell division in regions like root apexes, developing shoot buds, and young endosperm tissues. - (C) ABA (Abscisic Acid): Known primarily as a growth inhibitor and "stress hormone," it induces seed dormancy and triggers stomatal closure during droughts. - (D) Ethylene: A gaseous hormone that primarily regulates fruit ripening, triple response movements, and senescent tissue aging. Because cell division and cytokinesis are the defining functions of Cytokinin, it is the correct answer. This matches option (B).

Step 3: Final Answer:
The hormone that promotes cell division is Cytokinin.