Moura I.R.,Jardim Botanico Tropical IICT |
Simoes-Costa M.C.,Jardim Botanico Tropical IICT |
Garcia J.,Jardim Botanico Tropical IICT |
Silva M.J.,Jardim Botanico Tropical IICT |
Duarte M.C.,Jardim Botanico Tropical IICT
Acta Horticulturae | Year: 2012
Fronds of the tree ferns Cyathea australis (R. Br.) Domin, Cyathea cooperi (Hook. ex F. Muell.) Domin, Cyathea cunninghamii Hook. f. and Dicksonia antarctica Labill. were collected in "Estufa Fria", a cold greenhouse belonging to Lisbon Municipality. Surface sterilization of freshly isolated spores was optimised by comparing two sterilising agents (sodium and calcium hypochlorite) at different exposure times. Best results (0% contamination) were obtained with 5% (v/v) commercial bleach for 15 min. Sterilised spores were sown on solid (0.25% gelrite) or liquid media containing 1/2 strength Murashige and Skoog mineral salts and 2% sucrose. Cultures were incubated under 16h/8h light/dark or darkness conditions. Spore germination was obtained in the four species under study, both on solid and liquid media, but only under light conditions. For further growth and development, germinated spores were sub-cultured onto eleven different semi-solid culture media: MS minerals salts at 1/2, 1/10, 1/20, and 1/40 strength with 0 or 2% sucrose; 1/2 MS mineral salts supplemented with 150 mg/L of NaH2PO4 and 2% sucrose; 1/2 MS mineral salts with 2% sucrose and 2 mg/L BAP + 0.5 mg/L NAA; Dyer mineral salts. Sub-culture of the germinated spores onto a peat:perlite substrate was also experimented. Development of gametophytes was observed in all the culture media tested. Best results concerning gametophytes growth and development were observed on media with 1/2 MS mineral salts and 2% sucrose supplemented or not with 150 mg/L of NaH2PO4, and on Dyer mineral salts medium. In terms of sporophyte development, best results were obtained on culture medium supplemented with 150 mg/L of NaH2PO4.