European Journal of Biotechnology and Bioscience

European Journal of Biotechnology and Bioscience

ISSN: 2321-9122

Vol. 2, Issue 2 (2014)

Morphogenetic responses of explant types in Hypericum hookerianum

Author(s): Rajkumar Krishnamoorthi, Malathi R, Kalaivani R
Abstract: The Hypericum hookerianum Wight and Arnn, (Hypericaceae), a shrub of Palni and Nilgris hills of the Western Ghats, reported to have a range of antimicrobial, antiviral and antitumor properties, was selected for In vitro studies. Seeds of different accessions collected from natural areas were surface decontaminated and cultivated on Murashige and Skoog (1962) solid medium to produce seedlings at 60-80% efficiency. After 8 weeks, the seedlings were transferred to nutrient medium containing 0.5mg/l Kinetin (KN) for shoot multiplication. Number and length of the shoots proliferated upon the seedlings in presence of this cytokinin were significantly higher those obtained on basal medium. After 4 weeks, shoots raised from seedlings of different accessions were uniform except in the case of Bryant Park accession where the shoots regenerated into green (97%) and red (3%) types. Nodal explants (0.5cm) of the green plants were subcultured in nutrient medium containing different concentrations of cytokinin (KN, BAP) to obtain maximum number (9.6) of shoots per node at 0.5mg/l BAP. The shoots raised in presence of 0.5mg/l KN were relatively fewer but longer than those obtained on BAP. Comparative analysis of the responses of the nodal explants cultured in medium supplemented with the individual cytokinins (KN, BAP, TDZ) revealed that TDZ 1mg/l was the best to induce maximum number (3.4) of shoots compared to 2.0- 2.4 shoots obtained with other cytokinins in 4 weeks. Shoots transferred to rooting medium containing the auxins (IAA, IBA) formed upto 9.5 roots/ shoot in presence of 0.5mg/l IBA in 8 weeks. Isolated leaves of the shoots were induced to form roots. Roots were best formed in presence of IBA in 4 weeks, without callus formation. The 20+ roots obtained are being subcultured to establish exclusive root suspension culture in MS liquid medium. For want of time, logical end of obtaining such a culture for metabolic studies could not be reached
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