In vitro spore culture and reproductive aspects of the annual fern Anogramma chaerophylla (Pteridaceae).

Abstract

Anogramma chaerophylla belongs to a fern genus with annual sporophytes and potentially perennating gametophytes. In the studied area, Natural Reserve Punta Lara, the plants grow stressed mainly by pollution and the invasion of exotic species. As a part of a project on conservation of ferns inhabiting Buenos Aires province, the objectives of this work were to evaluate in Anogramma chaerophylla the conditions for in-vitro spore germination and to analyse the different stages of its reproductive cycle.
Spores were sterilized in an aqueous solution 10 % of NaCIO during different times and then sown in Petri dishes with Murashige & Skoog medium, without the addition of sucrose. The dishes were kept under
laboratory conditions, at 12 h light/ darkness photoperiod and a temperature of 22 (± 2) °C. After two weeks, the percentage of germination was 80%. The spore germination pattern corresponds to the Vittaria type and the prothallus development was Ceratopteris type. Gametangia developed first in the bended thalloid region of the prothallus and then bisexual tubercles originated near this zone. The sporophytes developed only in association with the tubercles. During culture in plastic pots the sporophytes gave origin to a second generation of prothalli. Our preliminary findings demonstrate that the in vitro culture technique is suitable for A. chaerophylla propagation as a strategy for ex-situ conservation.