African Journal of Biotechnology Vol. 6 (14), pp. 1643-1649, 18 July 2007   

ISSN 1684–5315 © 2007 Academic Journals        

Full Length Research Paper

High frequency shoot regeneration of Sterculia urens Roxb. an endangered tree species through cotyledonary node cultures

Town Mohammad Hussain^{1, 3}*, Thummala Chandrasekhar² and Ghanta Rama Gopal³

¹Department of Horticulture, Hamelmalo Agricultural College, Keren, and P.O.Box no: 397, Eritrea, North East Africa.

²Faculty of Biotechnology, Cheju National University, Jeju – 690 756, South Korea.

³Department of Botany, Sri Venkateswara University, Tirupati-517 502, Andhra Pradesh, India.

*Corresponding author. E-mail: dr.tmdhussain@yahoo.co.in. Phone: 002911401229 Fax: 002911401589.

Abbreviations: BA, N⁶-Benzyladenine; IAA, Indole-3-acetic acid; IBA, Indole3-butyric acid; 2iP, isopentenyl adenine; MS, Murashige and Skoogs medium; NAA, 1-Napthalene acetic acid; TDZ,  thidiazuron.

Accepted 2 April, 2007

A protocol is described for rapid and large scale propagation of an endangered, commercially and medicinally important tree species, Sterculia urens, by in vitro culture of cotyledonary nodes from 15 days old seedlings. Of the four different cytokinins (thidiazuron, isopentenyladenine, zeatin and adenine sulphate) evaluated as supplements to Murashige and Skoog medium (1962), thidiazuron at an optimal concentration of 2.27 μM was most effective in inducing bud break (83.0%). Although, multiple shoot formation was a function of cytokinin activity alone, enhanced frequency of shoot regeneration (93.3%) and number of shoots per explant (19.0) were observed by the addition of ascorbic acid (0.1%). Concentrations of all cytokinins tested above the optimum level reduced the frequency of shoot regeneration and shoot number. A proliferating shoot culture was established by repeatedly sub-culturing the original cotyledonary node on shoot multiplication medium (0.45 μM thidiazuron) after the second harvest of newly formed shoots. Rooting was best induced (80.0%) in shoots excised from proliferating shoot cultures on a quarter strength MS medium fortified with an optimal concentration of indole-3-butyric acid (9.80 μM).

Key words: Cotyledonary nodes, micro-propagation, multiple shoots and sterculiaceae.