Preconditioning of Nodal Explants in Thidiazuron-Supplemented Liquid Media Improves Shoot Multiplication in Pterocarpus marsupium (Roxb.)
Pterocarpus marsupium Roxb. (Fabaceae), commonly known as “Bijasal” or “Indian Kino,” is a potential herbal drug-yielding tree since ancient times. In the present study, an efficient micropropagation system was developed for propagation of this valuable forest tree by pretreating the nodal explant in thidiazuron (TDZ) in half-strength Murashige and Skoog (MS) liquid medium before their inoculation onto the full-strength MS semisolid medium containing meta-Topolin (mT), a new aromatic cytokinin, at different doses either singly or in combination with auxins. Among the treatments tried, nodal explants treated with TDZ (10.0 μM) for 8 days followed by transfer to MS medium containing mT (5.0 μM) + NAA (1.0 μM) were found to be most effective combination in inducing maximum shoot number (11.16 ± 0.16) with an average shoot length (4.9 ± 0.13 cm) and maximum regeneration frequency (85%). A proliferating shoot culture was established by subculturing the original nodal explants on shoot multiplication medium supplemented with meta-Topolin after each harvest of newly formed shoots. For root induction, basal end of isolated shootlets (≥ 4.0 cm) was treated with high dose of indole-3-butyric acid (150.0 μM IBA) solutions for 1 week followed by their transfer to half-strength MS supplemented with low doses of IBA (1.5 μM) in the medium which produced an average of (6.32 ± 0.26) roots with mean root length (4.05 ± 0.27 cm) in 80% shootlets, after 4 weeks of culture transfer. The regenerated plantlets with proper root system were successfully acclimatized to field condition with 75% survival rate.
KeywordsAxillary bud Meta-Topolin Morphogenesis Plant growth regulators Pretreatment Regeneration
Murashige and Skoog medium
α-naphthalene acetic acid
Plant growth regulators
Anees Ahmad is thankful to the Department of Biotechnology, Govt. of India, New Delhi, for financial support as a Junior Research Fellow under the Major Research Project (Vide No. BT/PR2189/PBD/17/744/2011 Dated 19.12.2012). The award of UGC-BSR Faculty Fellowship (2017) to M. Anis is duly acknowledged.
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