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The oak leaf fern, Tectaria zeylanica (Houtt.) Sledge, is an endangered fern in India, native to the Southeast Asian region. For the ex-situ conservation of this endangered fern, spores were collected and cultured aseptically on full-strength KC Medium with sucrose at pH 5.8. The spores are monolete with a prominent winged perispore. The exine ruptures at the laesura, and three or four germ filaments grow out, following a Vittaria-type germination pattern. The prothallial development was of the Aspidium type. Adult gametophytes are cordate and much broader than their length. Antheridia develop between 120 and 140 days. They are characteristically 3-celled, with a basal cell, a median cell, and an opercular cell. The female sex organs, archegonia, develop between 150 and 170 days. They are superficial and arranged on the lower side of the prothallus near the midrib and the meristematic region. Fertilization and subsequent development of the sporophytes were observed after four months. The highest percentage of sporophyte formation was observed on KC medium fortified with Kin 0.5 mg/l. Sporophytes had uniseriate, unicellular, and multicellular hairs, similar to those found on adult prothalli. The highest percentage of root formation was observed in the medium with IBA + NAA (1.0 mg/l). The in vitro raised plants showed a 54% establishment during hardening in the field. The present study has established a reproducible protocol for the ex-situ conservation of this endangered oak leaf fern.
Sundari et al. (Thu,) studied this question.