Direct Organogenesis from Rhizome Explants in Marsilea quadrifolia L.: A Threatened Fern Species

Abstract

An efficient micropropagation protocol has been developed for Marsilea quadrifolia L. through direct organogenesis. The mature rhizomes were used as explants and successfully sterilized using 0.1% HgCl2 for the establishment of cultures. The multiple shoots were differentiated from the explants on Murashige and Skoog (MS) medium augmented with 6-benzylaminopurin (BAP). Full strength MS medium was reported to be effective for the induction of sporophytes from the rhizomes after four weeks of inoculation. Maximum response (96%) with average of 6.2 shoots (2.72 cm length) was achieved on full strength of MS medium augmented with 0.5 mg/L BAP in culture initiation experiments. The cultures were further proliferated in clusters (79.0±0.37 shoots per explant) with stunted growth on half strength MS medium supplemented with 0.25 mg/L BAP after four weeks. These stunted shoots were elongated (5.30 cm long) on half MS medium devoid of growth hormones. Root induction and proliferation (3.0–4.0 cm long) were observed after 4th subculture of sporophytes on hormone-free half strength MS medium. The rooted plantlets were hardened in the fern house for 4-5 weeks and transferred to the field with 92% survival rate. There were no observable differences in between in vivo grown and in vitro propagated plantlets in the field.