Question

In tissue culture, roots can be induced by

• A. Lower concentration of cytokinin and higher concentration of auxins.
• B. Only cytokinin and no auxins.
• C. No cytokinin and only auxins.
• D. Higher concentration of cytokinin and lower concentration of auxins.

Answer 1

Answer: (A)

Lower concentration of cytokinin and higher concentration of auxins.

The composition of the medium, particularly the plant hormones and the nitrogen source (nitrate versus ammonium salts or amino acids) have profound effects on the morphology of the tissues that grow from the initial explant. For example, an excess of auxin will often result in a proliferation of roots, while an excess of cytokinin may yield shoots. A balance of both auxin and cytokinin will often produce an unorganized growth of cells, or callus, but the morphology of the outgrowth will depend on the plant species as well as the medium composition. So, in tissue culture roots can be induced by lower concentration of cytokinin and higher concentration of auxins. Thus, option A is correct.