2021, VOLUME 8 ISSUE 1Pages: 36-41
Callus induction and plant regeneration from cotyledonary leaf explants of Oroxylum indicum (L.) Vent. - An endangered medicinal tree
C. K. Smitha*, P. S. Udayan, T. K. Bindu and T. T. Maju
*Post Graduate Department of Botany and Research Centre, Sree Krishna College, Guruvayur, Ariyannur P.O, Thrissur-680102, Kerala, India
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Oroxylum indicum is a medicinal tree renowned for the presence of a large number of bioactive compounds and a wide range of healing properties. Several biochemical and molecular studies are ongoing in this plant as per the literature survey. The present study is undertaken to develop a simple and reliable protocol for plant regeneration from callus, so as to exploit the regeneration potential of this tree. The cotyledonary leaf explants from the in vitro raised seedlings produced callus in MS medium supplemented with 0.5–2.0 mg l-1 Benzylaminopurine (BAP) alone and in combination with auxins- 0.5 mg l-1 2,4-Dichlorophenoxyacetic acid (2, 4-D) and 0.5 mg l-1 Indole-3-acetic acid (IAA). Silver nitrate (AgNO3) was used as an additive in a concentration of 1 mg l-1, in all the trials. Callus raised in all combination of growth regulators showed organogenesis in the second cycle of culture. MS medium with the combination 2 mg l-1 BAP and 0.5 mg l-1 2, 4-D produced a mean number of 61.33 buds per explants, which was the maximum of the observed results. Direct organogenesis was noted in explants raised in 2 mg l-1 BAP supplemented MS medium. The shoot buds were cultured in MS medium fortified with 0.2 mg l-1 BAP alone and in combination with 0.5 mg l-1 IAA or 0.5 mg l-1 Gibberellic acid (GA3) for elongation. GA3 found to be the best combination with BAP for obtaining shoots with better length (6.13 cm) and healthy leaves. Shoots thus obtained were rooted in full or half-strength MS medium with 0.5–1.0 mg l-1 IAA or Naphthalene acetic acid (NAA). Half strength MS with 1.0 mg l-1 IAA produced 62% rooting, with a mean number of 7.66 roots per shoot. Rooted micro shoots were acclimatized in 1:1 mixture of autoclaved sand and vermiculite, before transferring to the field. About 62% of plantlets survived by this process.