Q. You are given a tissue with its potential for differentiation in an artificial culture. Which of the following pairs of hormones would you add to the medium to secure shoots as well as roots?
(a) Auxin and abscisic acid
(b) Gibberellin and abscisic acid
(c) IAA and gibberellin
(d) Auxin and cytokinin
Solution :
Correct option : D 1.Auxin and cytokinin are the two growth hormones that favour cell division and differentiation. 2.Auxin promotes root development, cell division and differentiation of xylem. 3. Cytokinins promote cytokinesis which means a division of cells and are generally secreted in the areas where rapid cell division occurs. 4.The proportion of cytokinin to auxin is regulated in calculated proportion to induce differentiation in the callus. 5.Lower levels of cytokinin and higher levels of auxin promote the formation of roots and higher levels of cytokinin and lower levels of auxin concentrations promote differentiation of shoot.