Full Length Research Paper

In vitro propagation of Hoya wightii ssp. palniensis K.T. Mathew, a highly vulnerable and endemic species of Western Ghats of Tamil Nadu, India

S. Revathi Lakshmi¹, J. H. Franklin Benjamin¹, T. Senthil Kumar², G. V. S. Murthy³ and M. V. Rao¹*

¹Department of Plant Science, Bharathidasan University, Tiruchirappalli 620 024, Tamil Nadu, India.

²Department of Industry University Collaboration, Bharathidasan University, Tiruchirappalli 620 024, Tamil Nadu, India.

³Botanical Survey of India, Southern Circle, Coimbatore- 641 003, Tamil Nadu, India.

*Corresponding author. E-mail: mvrao_456@yahoo.co.in.

Abbreviations: AA, Ascorbic acid; BA, 6-benzyl adenine; CH, casein hydrolysate; CA, citric acid; IAA, indole-3-acetic acid; IBA, indole-3-butyric acid; KN, kinetin; NAA, α- naphthalene acetic acid; TDZ, thidiazuron; YE, yeast extract; 2-iP, 2- isopentenyladenine.

Accepted 14 August, 2009

   Abstract

In vitro propagation of Hoya wightii ssp. palniensis (Asclepiadaceae), a highly vulnerable and endemic plant species of Western Ghats, Tamil Nadu, India was carried out. Shoot tip explants were cultured on MS medium fortified with cytokinins (KN, BA, 2-iP and TDZ) in various concentrations and in combination with auxins (IBA, IAA and NAA). High frequency of shoot bud proliferation and multiplication was observed on KN (4.65 µM) + IBA (1.47 µM). Multiple shoot induction efficiency was increased on ascorbic acid (100 mg/l) supplemented medium along with KN (4.65 µM) +IBA (1.47 µM). Rhizogenesis was observed on MS medium supplemented with IBA (0.98 µM), plantlets produced through micropropagation were hardened with the survival success of 56%. The efficient plantlet regeneration protocol developed would aid ex situ conservation of this vulnerable species.

Key words: Hoya wightii ssp. palniensis, in vitro propagation, Asclepiadaceae, plant growth regulators, ascorbic acid, micropropagation.