In vitro regeneration potential of foliar explants of Malaxis acuminata D. Don.: A therapeutically important terrestrial orchid

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 with sucrose (3%, w/v) and NAA (311M) + BA (311M). 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 (311M 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.