Effect of explant source and different hormonal combinations on in vitro regeneration of Heracleum candicans Wall: An important medicinal herb

In vitro regeneration of plants is influenced to a great extent by genotype, the type of explant used, media composition and plant growth regulators. This research was devised to study the effect of explant source and different hormonal combinations on the in vitro regeneration of Heracleum candicans. Two different explants viz; leaf and petiole were used to investigate their morphogenic response on MS medium supplemented with different concentrations of auxins (2, 4- dichlorophenoxyacetic acid and indole 3-acetic acid) and cytokinins (6-benzyl amino purine and kinetin) either individually or in combinations. Petiole explants were most responsive for callus production as well as shoot regeneration. 2,4-D at 3 mg/L proved to be the best concentration for callus induction. For shoot regeneration, MS medium supplemented with BAP at 3 mg/l and IAA at 2 mg/l proved to be effective in production of 21±0.7 mean number of shoots in 90% of cultures. Regenerated shoots were separated and rooted on full strength MS basal medium producing 6.9 average numbers of roots per shoot in 90% of cultures. The present research yielded a suitable explant and optimum concentrations of different plant growth regulators for in vitro regeneration of this important medicinal herb.   Key words: Heracleum candicans, leaf, petiole, callus, shoot regeneration.