Gametophyte Propagation and Sporophyte Formation of Asian Chain Fern [Woodwardia japonica (L. f.) Sm.] Under Various Medium Conditions In Vitro and Ex Vitro

This study investigated a suitable method that could be applied for Asian chain fern [Woodwardia japonica (L. f.) Sm.] to propagate gametophytes and promote sporophyte formation. The gametophytes used in all experiments were obtained from germinated spores in vitro and were subcultured at 8-week intervals. The most appropriate media for gametophyte propagation was identified by culturing 300 ㎎ of gametophyte in Murashige and Skoog (MS) basal medium (1/8, 1/4, 1/2, 1, 2), and Knop medium for 8 weeks. As a result, fresh weight of the gametophyte was increased by 56.7-fold on MS medium. Moreover, antheridium formation as well as gametophyte growth was improved on MS medium, especially. To improve the sporophyte formation ex vitro, 1.0 g of gametophyte was ground with distilled water and spread on eight combinations onto four different culture mediums, such as bed soil, peat moss, perlite and decomposed granite. Then generation and growth of sporophytes were investigated after cultivation for 10 weeks. As a result of this experiment, peat moss had a promotive effect of sporophyte formation at single-use and mixed culture soils. In particular, a mixture of bed soil, peat moss and perlite in a 1:1:1 ratio (v/v/v) led to the accelerated formation (782.5 ea/pot) and the frond growth of sporophytes. This included increases in length and width of fronds. However, promotive effect of gametophyte growth and sporophyte formation was not found at single-use and treatment with high ratio of bed soil.