PLANT REGENERATION THROUGH CALLUS INDUCTION ON MEDICINAL HERB Viola odorata - ROLE OF PLANT GROWTH REGULATORS AND EXPLANTS

Viola odorata is a hardy herbaceous flowering perennial medicinal plant mainly used as an herbal cure in the diabetes and cancer, which have a low germination rate under normal laboratory conditions because of hard seed coat and thermal dormancy. To examine the effects of some plant growth regulators on callus induction and plant regeneration of V. odorata, various explants such as leaf, petiole and root pieces were transferred to Petri dishes containing MS medium supplemented by different concentration and combination of plant growth regulators NAA, 2,4-D and KIN. The highest frequency of callus induction (80%) was occurred in MS media containing NAA (2 mg l^-1) + 2, 4-D (2.5 mg l^-1) on leaf explants. The best treatment for rooting was the medium containing NAA (3 mg l^-1) + 2, 4-D (2.5 mg l^-1). After transfer the calli to regeneration media, results showed the best response to regeneration was occurred in MS media containing GA3 (0.5 mg l^-1) + TDZ (2 mg l^-1) also GA3 (1 mg l^-1) + TDZ (2 mg l^-1). Maximum mean number of shoots and highest length of shoots were obtained in MS media supplemented with GA3 (0.5 mg. l^-1) + TDZ (2 mg. l^-1).