Morphogenesis in several cultivars of boston fern

Stolon tips from sporophytes of Nephrolepis exaltata c.v. 'bostoniensis' and its cultivars N. exaltata c.v. 'scotti' and N. exaltata c.v. 'dwarf boston' were aseptically cultured on Murashige Fern Multiplication Medium modified by the addition of 2,4-dichlorophenoxyacetic acid (2,4-D) 0.5-4.0 mg/1. Callusing occurred in the apical and lateral buds of the stolon tips in four to six weeks. Histological sections demonstrated that the callus originated from the provascular tissue of the apical meristems of the stolon buds. Basal medium with 3% sucrose and 0.5 mg/1 2,4-D produced the greatest increase in fresh weight of subcultured callus tissue in all cultivars.

Organogenesis into shoots and roots from undifferentiated callus tissue occurred on basal medium with combinations of 5x10^-7m kinetin (K) plus 5x10^-7m naphthalene acetic acid (NAA), 10^-6M K plus 10^-5M NAA and 10^-6M K plus 5x10^-7m NAA in 12 weeks. Attempts to induce organogenesis with indole-3-acetic acid (lAA) and isopentenyl adenine (2ip) produced only roots at all hormone levels tested. Viable suspension cultures were produced from stolon callus of all cultivars employing a liquid basal medium containing 0.5 mg/1 2,4-D. Callus clones from single cells in suspension cultures were obtained by the Bergmann Technique. The clones were transferred to morphogenic medium and formed complete new plants. Thus, the morphogenic totipotency of pteridophytes has been achieved with the production of whole sporophytes from callus tissue and single cells of three Nephrolepis cultivars.