Question

Shoot bud formation in tissue culture is promoted by

• A. high auxin : low cytokinin
• B. low auxin : high cytokinin
• C. auxin : sucrose
• D. $G{A}_3$ : cytokinin

Answer 1

The correct option is B low auxin : high cytokinin

The technique of growing plant cells, tissues or organs in a sterile culture medium under controlled environmental conditions is called plant tissue culture.
The culture medium consists of several plant hormones (auxin, cytokinin and gibberelins), sucrose etc. The auxins facilitate cell division and root differentiation. The cytokinins induce cell division and shoot development. Hence, low amount of auxin and high amount of cytokinins induce shoot bud formation.
$G{A}_3$ is the primary gibberelin that is found in the tissue culture medium. It induces the growth of the adventitious roots. Sucrose acts as the source of energy for the plant cells in the culture.