Q. In callus culture, roots can be induced by the supply of :
(a) Ethylene
(b) Gibberellin
(c) Cytokinin
(d) Auxin
Solution : Correct option : D Auxins are the plant growth hormones that induce root differentiation and apical dominance mainly .Cytokinins are the plant growth hormones that promote cell division in shoot apical meristem and differentiation in root apical meristem. It works antagonistically to auxin to balance the growth with development in the shoot and root apex .Gibberellins promote internodal growth (bolting), especially in dwarf and rosette plants, like cabbage, when kept under short days .Ethylene is the gaseous hormone that stimulates growth and development of floral organs and promotes fruit ripening.
