In vitro micropropagation of an endangered orchid species (Orchis catasetum) through protocorm: the effect of plant growth regulators and iron Nano-chelate

Many orchid species are threatened with the danger of extinction. Here, a protocol was developed for high frequency in vitro multiplication of an endangered orchid, Orchis catasetum using plant growth regulators and iron Nano-chelate. Protocorms, as explants were cultured on Murashige and Skoog (MS) medium fortified with different concentrations of N6-benzyladenine (BA), α-naphthaleneacetic acid (NAA) and indole-3-butyric acid (IBA) either individually or in combination and iron Nano-chelate. A combination of 0.5 mg l-1 BA and 0.5 mg l-1 NAA was found to be suitable for maximum protocorm-like bodies (PLBs) regeneration (18.84/plantlet) from protocorm explants. The maximum number of root (6.94/plantlet) and leaf (9.50/plantlet), also the highest plant height (124.10 mm/plantlet) and root length (178.90 mm/plantlet) were obtained on MS medium supplemented with 0.5 mg l-1 BA a long with 0.5 mg l-1 NAA. Related to the effect of iron Nano-chelate, maximum plant height (82.79 mm/plantlets), maximum root number (4.76/plantlets) and root length (87.53 mm/plantlets) were observed in explants cultured in MS medium enriched with 0.13 mg l-1. Plantlets were transplanted to pots filled with perlite, wood pieces, ionolite and mineral cartridge shell (1:1:1:1), also perlite individually and transferred to the greenhouse. Upon ex vitro transfer, 100% of plants survived.