Name the plant hormone responsible for the growth of the stem. A. Gibberellin B. Auxin C. Cytokinins D. Ethylene
Hint: The hormone responsible for stem growth also promotes flowering. It was discovered by the in the year 1935 and was isolated from the fungus Gibberella fujikuroi.
Complete answer: Plant hormones are organic chemicals or substances which regulate plant growth and development. Some of these favor growth of plants while some are growth inhibitors. These substances can control numerous processes in plants viz. seed-germination, root and shoot growth, flower production, etc. Gibberellin is a plant hormone. It refers to the longest-known classes of plant hormones. These hormones regulate various developmental processes in plants including flowering, dormancy, stem elongation, germination, flower development, and leaf and fruit senescence. Precisely, the gibberellin hormone is a plant growth regulator. These are abbreviated as ‘GA’.
So, the correct option is A. Gibberellin Note: Cytokinins promote cell division in plant cells. Abscisic acids are growth inhibitor hormones. Auxin hormones are responsible for the elongation of plant cells.