Drynaria quercifolia is a highly medicinal fern used traditionally all over the world to treat a variety of ailments. But due to indiscriminate collection and destruction of habitats, it is facing the verdict of being endangered. So it is high time to adopt the various conservation measures including its in vitro propagation. In order to conserve the species in situ, in vitro culture of spores of the plant was tried. The spores were found to germinate only on MS - Z4 medium (Full MS+1mg/L IAA+5mg/L Kinetin+20%CM+300mg/L CH). All other media used failed to produce prothallus. After inoculation, it took about 30 days to germinate. After development of the Prothallus and subsequent development sporophytes, the plantlets were transferred in different media but the best growth was observed in PNT-2 media (Full strength Parker and Thompson +5mg/L IAA+2mg/L Kinetin) where proliferation of vegetative fronds and rhizome were recorded.

Helminthostachys zeylanica (L.) Hook is a very rare and endangered medicinal fern available in Tilbhum Reserve forest of Karimganj District. The spores of the fern were collected, dried and cultured in different tissue culture medium. Among the medium tried, the fern germinated well in Murashige and Skoog (1962) and Parker – Thomson Basic C fern medium. Gametophytic body developed from the germinating spores after 55days of germination. Sporophytes developed after fertilization of male and female gametes developed from antheridia and archegonia respectively. Different stages of development of male and female gametophyte were studied in course of development. For better growth of the cultured plants different growth regulators modification was also tried and analysis of result was done.

Papilionanthe teres (Roxb.) Schltr. is a medicinal orchid found in all reserve forests of Southern Assam, India. Mature pods of Papilionanthe teres were collected from natural plants and seeds were inoculated in Murashige and Skoog (MS), Knudson C (KnC), Commercial Orchid Maintenance(OMM) and Commercial Orchid Maintenance Replate (OMR) medium(HiMedia). Best germination and growth were observed in commercial orchid maintenance replate medium supplemented with 2mg\L IAA and 5mg\L KN. Growth of root, shoot were measured after three months of germination. Shoot tip and nodal explant of the plant were tried in different medium viz. MS, White, B5, KnC, Commercial Orchid Maintenance medium etc. containing different growth regulators modification for micro propagation. For phytochemical screening qualitative tests were performed from the dried powder of the plants. From the qualitative test it was observed that the plant extracts contain alkaloid, flavonoid and tannin in petroleum ether extract and alkaloid, tannin and saponin were found in ethyl acetate extract. Steroid was found present in methanol and benzene extract. Flavonoid was found only in acetone extract.

Spores of Bolbitis costata were cultured in MS medium supplemented with and with out hormone and sugar supplementation. Spores germinated after 50 days of inoculation. In order to study the effect of different growth regulators on different characters viz. germination percentage, fresh and dry weight of prothallus and sporophytes were measured at specific intervals. Maximum germination percentage was observed in MS medium supplemented with 0.2 mg/L IAA. Growth of gametophytes and sporophytes were recorded periodically. Medium supplemented with 0.4 mg/L IAA showed maximum growth of the gametophytes. After 5 months the sporophytes developed from the gametophytes. Maximum growth of sporophytes was observed in medium supplemented with 4mg/L IAA+5 mg/L KN+0.2 mg/L IBA. The same medium also showed maximum fresh and dry weight of sporophytes. Regenerated plants were transferred in different potting mixtures. Maximum survival percentage was observed in the mixture containing brick bats + charcoal +dried moss + dried leaf mold (1:1:1:1).