Question

Callus can form shoot or root by changing ratio of

• A. auxin to gibberellin
• B. auxin to cytokinin
• C. cytokinin to ethylene
  
• D. gibberellin to cytokinin

Answer 1

The correct option is B auxin to cytokinin

Plant cell growth regulators (e.g. Auxins, Cytokinins and Gibberellins) i.e. plant hormones play an important role in growth and differentiation of cultured cells and tissues. The auxins facilitate cell division and root differentiation, induce cell division, cell elongation, and formation of callus in cultures. A high cytokinin to auxin ratio supports the formation of shoots, whereas a high auxin to cytokinin ratio favours formation of roots. A balanced ratio favours production of callus.