Gametophyte Development of Athyrium niponicum

The spores of the Athyrium niponicum were cultured in the mixed soil.The spore germination and gametophyte development were observed and photographed under microscope.The result indicates that the spores are dark-brown,monolete,and bean-shaped in equatorial view and elliptical in polar view.The spores germinate about one week after being sowed,the germination is of the Centripetal-type while the gametophyte development is of the Adiantum-type.The prothallial plates begin to form when the filaments are 7-11 cells long.The young prothalli develop in two weeks after being sowed and the mature prothalli are cordate.Unicellular hairs occur on the surface of the prothalli.The antheridia appear about 20 days after being sowed.They are like pellets and formed by three cells.The archegonia form one week later than that of the antheridia.The archegonial neck is 3-5 cells high at maturity.Young embryos growing from the prothalli can be observed about 2 weeks after fecundated.