Study On The Development Of Protonema In Family Bryaceae

In the life cycle of bryophyte,the protonema stage is the first stage of the spores germinating into gametophytes and the stage is essential for the gametes. In plant kingdom,having a protonema stage after spore germination is a specific character of moss and a marked difference compared with other plant group. Studies on the spore germination and protonema development of the mosses are important to clarify the relationships between each taxonomical group and the systematical evolution.This stage has a close relationship with the phylogenetic classification,ecological adaptability,reproduction and the evolution of bryophyte. Studies on the protonema development and culture has an important theoretical and practical significance.Sporeling-type characters of 23 moss species (belonging to 4 families and 7 genuses) have been studied and 19 species (belonging to 2 families and 3 genuses) are reported firstly.Bryaceae is one of the biggest families in the mosses.There are 20 generas and 1,400 species in the world approximately of Bryaceae. In our country,there are 11 generas and more than 170 species. Bryaceae plants are acrocarpous mosses,their morphological structure are more complex in evolution than other types. Bryaceae species has a widely ecological adaptability. They usually grow in a mat formation to keep water drying out and they are pioneer plants for sand– fixation. Bryaceae taxon are small and delicate which have highly decorative value,some of them has medical value.They was also good materials in biology experiments.Therefore,the paper takes Bryaceae plants for research materials. Author choose one species of family Funariaceae , one species of family Mniaceae relationship closer to family Bryaceae,and one species of family Grimmiaceae relationship faraway from Bryaceae for contrapositive materials,try to analyze the phylogenetic relationship between Bryaceae and relative grougs.The main results are as follows:1)Summarize the economic value and ecological functions of bryophytes; Studied the significance of mosses spore germination and Protonema Development; summarize the history of protonema study in domestic and foreign;and introduced the new progress on Protonema researche in the areas of CAM in Ca2 +·CAM signaling system,the plant hormone,light form completed and the gravity response,cell and molecular biology,biological pharmacy since the 1990s.2)Describing the characteristics of 23 species of their spore germination, protonema development and gametophyte differentiation by microscopy in this research.21 characteristics of 9 characteristics have been chosen to analyze the developmental features of the 23 bryophytes species. Having supplemented and perfected the classified basis of sporeling-type classifing and analyzing the spore germination and protonema developmental features of the 23 species which have treated in this research.Discussing the relationship among the sporeling-type, phylogenetic classification,ecological adaptation, reproduction strategies and systematical evolution.3)In the development and utilization of bryophytes, the principal problem we have to solve are culture and propagation. To get a large number of pure and aseptic materials by tissue culture of bryophytes is the basis to carry out scientific research and production.The paper explored the in-vitro cultivation of protonema and gametocyte. Establish the foundation for bryophytes large-scale cultivation.