Studies On The Fern Propagation Techniques And Gametophyte Development

There are 12,000 species of ferns all over the world, and more than 2,600 species in China, covering more than one fifth of the whole species of the world. And there are 500～600 specific species in our country. Recent years, some rare ferns are endangered to extinction because of the environmental degaradation and unreasonable exploitation and utilization. It is urgent to strengthen its correlative fundamental research, such as propagation and germplasm conservation. To investigate the propagation procedure of ferns, we have made research on spore fertilization technology and gametophyte development for almost three years. The main results are showed as follows:(1) Spores were cultured in the inorganic mediums and soils respectively. Tests were conducted to evaluate the effects on various sterilization procedures, in various mediums and with different light intensity and tempreture on spores germination and gametophyte development of Alsophila spinulosa, A. gigantean, A. odophylla, A. metteniana and Drynaria roosii. The results exhibited that the spores could germinate in all of the mediums used in the experiment, but the spore germination time and germination rate were infected. Among different strengths of MS basal mediums used, although a higher germination was observed in 1/5 MS, further growth of gametophytes in the former mediums was slow.Therefore, low salt concentration was not good for gametophyte growth. In our experience, spores of Cyatheaceae germinated fastest in the 40μmol·m-2·s-1 light intensity, and the germination rate was the highest, as the light intensity became higher, the germination time prolonged, and the germination rate became lower. When the light intensity reached 130μmol·m-2·s-1, the morphology of the gametophyte changed. And the maximum germination of Drynaria roosii was obtained in the 100μmol·m-2·s-1 light intensity. In the dark, spores of Cyatheaceae could germinate and developed to filaments, but could not developte to gametophytes.(2)The spores were cultured in the inorganic medium, and the gametophyte development were observed and recorded under microscope. The spore germination, and the formation of gametophyte in each development stage and the time required to reach every stage were recorded, which would be useful for the further studies of ferns propagation technology, evolutionary process and taxonomy of ferns. The germination of the Cyatheaceae are the Cyathea-type and the gametophyte development are of the Ceratopteris-type. While the germination of the Drynaria roosii is the Vittaria-type and the gametophyte development is the Drynaria-type.(3) The culture substrates for the Drynaria roosii ceedlings cultivation was also been studied, and the mixed soil (turf: soil: sand =1:1:1) was the best growing medium for Drynaria roosii to grow up.