The Gametophyte Development and Endangerment Mechanism of Neocheiropteris palmatopedate (Polypodiaceae,Fern)

The spores of Neocheiropteris palmatopedate were cultured in improved Knop′s medium, in-situ humus soil and red soil respectively. Spore germination and gametophyte development were observed under optical microscope and dissecting microscope, and the impact of four culture methods on the gametophyte development and sexual reproduction was compared. On these experiments, its cause of endangerment was analyzed. The results showed that the mature spores are yellow-brown, monolete, and bean-shaped in equatorial view and elliptical in polar view. The pattern of spore germination is of the Vittaria-type and the gametophyte development of the Drynaria-type. The adult prothalli are cordate. Trichomes occurred in prothallus stage. The long period of sexual reproduction and the low rate at which gametophytes develop into sporophytes are the main reason for the endangerment of Neocheiropteris palmatopedata in sporophyte generation. Moreover, the extremely slow development of gametophyte and time interval between the appearance of antheridia and archegonia resulting from the inherent physiochemical property of red soil make it impossible to fertilize and generate sporophyte. Therefore, the disappearance of humus soil under woods and the appearance of red soil caused by primary vegetation destruction aggravate the endangerment situation of Neocheiropteris palmatopedata.