In vitro organogenesis and plant regeneration of Thymus serpyllum L.: an important aromatic medicinal plant

An efficientin vitropropagation system has been developed for the rapid micropropagation ofThymus serpyllumL. (Banajwain), an aromatic medicinal herb from nodal explant on MS medium. Phenolic leaching and high rate of contamination was the most significant problem in establishingin vitroculture ofThymus serpyllumwhich was overcome by preparing explants in an antioxidant ascorbic acid (1000 ppm) at 6 degrees C for 45 min and addition of the same antioxidant (50 mgl(-1)) to the MS medium. The frequency of shoot production was influenced by different cytokinins (Kn, BAP, and Kn + BAP) and 95.56% shoot induction was observed when MS medium was supplemented with 1.0 + 2.0 mgl(-1)(Kn + BAP). The maximum average number of shoots 16.93 +/- 2.15 and average length (3.98 +/- 0.55) was recorded when MS medium have 0.5 + 2.0 mgl(-1)(Kn + BAP). Thein vitroregenerated microshoots were rooted on MS and half strength MS medium and there was significant difference in root induction on both media under the influence of auxins (IAA, IBA, and NAA). The maximum average number (11.67 +/- 3.03) and average root length (3.88 +/- 0.71) was reported in half MS medium having 1.0 mgl(-1)IBA. The complete regenerated plantlets were acclimatized under growth chamber before transferring to the earthen pots and showed 90% survival. Graphical abstract