In Vitro Regeneration Potential Of Foliar Explants Of Malaxis Acuminata D. Don.: A Therapeutically Important Terrestrial Orchid

Abstract

Malaxis acuminata is a terrestrial orchid whose rhizome is medicinally  important. The dried pseudobulbs are used in preparation of ‘Ayurvedic drug’  ‘Chyawanparash’, an energetic herbal tonic and to cure tuberculosis. Due to  various anthropogenic activities and excessive extraction for medicinal purposes, the species is under constant threat in its natural habitats. A successful attempt  was made to propagate this species using foliar explants from axenic source as  alternative explants. The meristemetic loci invoked from the cultured leaf  explants within 4-5 weeks of culture on MS medium fortified withsucrose (3%,  w/v) and NAA (3 µM) + BA (3 µM). The foliar explants were cultured in  different orientations, and optimum response was recorded with the explants  cultured horizontally on culture medium in comparison to up side up and  reverse orientations. Under this condition, as many as 26 shoot buds developed.  The resultant shoot buds converted into plantlets with well developed roots on  MS medium supplemented with sucrose (3%) and NAA + BA (3 µM each) with average plant height, number of leaves and number of shoots 2.4 cm, 4.5, 18.0,  respectively. The hardened regenerates when transferred to community potting  mix [prepared by mixing charcoal pieces, chopped forest litters, coconut husk,  sand and black soil at 1:1 ratio] showed about 75% survival of transplants after  two months.