Question

The combination of auxin and cytokinin, which is likely to induce shoot differentiation in tobacco callus is

• A. Lower concentration of cytokinin and higher concentration of auxin
• B. Higher concentration of cytokinin and lower concentration of auxin
• C. Only auxin
• D. Only cytokinin

Answer 1

Answer: (B)

Higher concentration of cytokinin and lower concentration of auxin

Callus is an undifferentiated mass of cells which contains totipotent cells. An intermediate ratio of auxin and cytokinin promotes callus induction, while a high ratio of auxin-to-cytokinin or cytokinin-to-auxin induces root and shoot regeneration respectively. It has been widely used, for example, in the propagation of economically important traits and the introduction of transgenes.

Therefore, the correct answer is option B.