Optimizing callus induction, indirect plantlet regeneration and evaluation of antioxidant enzyme activities in Tecoma stans L

Abstract

An efficient protocol has been designed for high frequency indirect shoot organogenesis and plant establishment for Tecoma stans, an anti-diabetic shrub from inter node segment derived callus. Maximum organogenic callus induction frequency (75 %) was recorded on Murashige and Skoog medium augmented by 7.5 µM 2, 4 – D. Efficient shoot bud differentiation via de novo callus formation was achieved using various hormonal concentrations. The highest shoot regeneration frequency, with an average of 24.4 ± 0.74 shoots / per callus clump having 5.96 ± 0.43 cm mean shoot length, was achieved on MS medium enriched with 7.50 µM mT + 0.50 µM NAA, after 8 weeks of incubation. Effective (95 %) in vitro rhizogenesis among regenerated shoots were revealed on ½ MS containing 1.0 µM IBA with maximum (12.4 ± 0.50) number of roots having average mean length (5.92 ± 0.44) cm per excised shoot, after 4 weeks of incubation. Plantlets with fully developed root / shoot systems were effectively acclimatized, with a 90.0 % success rate, and planted in pots filled with soil. The micro-propagated plants exhibited healthy growth pattern with normal morphology. In addition effect of environmental conditions on acclimatization was studied via evaluating the biochemical and antioxidant enzymatic activities such as CAT, SOD, H₂O₂ and GR on weekly basis.