The Effect Environmental Factors On Spores Germination And Gametophyte Development In Cibotium Barometz

Cibotium barometz is a second class state protection wild specie and the only Chinese member of the family Dicksoniaceae, which grow in the humid and valley places. It is also used in Chinese traditional medicine in China. The specie with the distribution range from the southwest to the southeast province. It's quantity and distribution are decreasing, and many population is endangered.This paper studies three distribution of C. barometz in chongqing JinYun mountain nature reserve, Sichuan ShuNan bamboo-sea nature reserve, the nature reserve of ChiShui in GuiZhou. And statistics soil pH value, crown density and companion species in three distribution. The results show that the distribution of C. barometz can grow in acid soil, humid and high crown density environment; Spore mature span over 6-12 months. All community structure is similar with each other in every distribution, which companion species are similar types of plants as others, especially Arachniodes falcate and Alpinia japonica is the most. In ChiShui distribution, the areas has low soil moisture, altitude and high temperatures than other areas, so this experiment spores of selecting ChiShui area.1)We sterilized training spores in different of pH, temperature and light intensity gradient. The results showed that range:Between pH3.0 to pH6.0, spores can germinate and develop to gametophyte but no significant difference, in pH7.0 spores have without germination. In 20-30℃can develop into the gametophyte. With the rise of temperature, the time is shortened to mature gametophyte. When temperatures is rise to 35℃, spores completely have no germination. All the darkness, spores can not germinate. light intensity in 1200 lx to 3600 lx, spore can germinate and develop into gametophyte. the spore not germinate when strength of illumination up to 4800 lx. Results show that C.barometz spores can tolerate certain environment of high temperature and acidity soil, but against high light intensity. In order to in a short time gain a mature gametophyte, it could be appropriately increase the temperature, lower pH, moderate illumination.2) In order to find their sexual differentiation characteristics and regulars, set up different temperature, pH and illumination gradient to observe C.barometz gametophyte sex differentiation. Draw the following results:in the first seven weeks, under different temperature, pH3.0 most gametophyte is differentiation into unisexual gametophyte, increaseing the pH, the unisexual gametophyte is reverse to bisexual gametophyte. The gametophyte develop into a female gametophyte under 25℃, while in the gametophyte develop into male gametophyte under 30℃first. After 10 weeks, most of unisexual gametophyte is reverse to bisexual gametophyte. but the rates of fertilized is extremely low. In a different light intensity, the gametophyte in 1200 lx is more easily grow up to male gametophyte than formed under 2400 lx. The C.barometz gametophyte make different responses to different temperature, pH, lighting and time. Using the GML we can find that temperature and pH are the key environmental factor for sex differentiation. this may be due to the environmental factors caused by the different amount of Antheridiogen secreted is different. There is a need for study further.3)In order to find the relationship between Cibotium barometz and its companion species---A. falcate and A. japonica, we used aqueous leachates of the two companions to deal with C.barometz spores. spores were sown on MS culture which contained different concentration of aqueous leachates of the two companions. Observed and recorded the germination and gametophyte development. The Result showed that all leachates inhibited and delayed the C. barometz spores germination and rhizoid elongation was inhibited.It also had obvious inhibition to the prothallus formation and sexual differentiation, And the higher concentration, the more obvious inhibition aqueous leachates of the two companion species. The two companion species have allelopathic effects on the spore germination and gametophyte development of C. barometz. And it may have an influence on sporogon ontogenesis and the population expansion.Comprehensive analysis:through the ChiShui C.barometz spore different conditions of the culture, using microscopy techniques, observation records spore germination and the gametophyte development process. All data analysis is used spss16.0 statistical analysis software. all results show that the spore germination has certain adaptability, and field community survey conform. The experiment results reveals its archegonium and sperm gametophyte is not synchronous development mature,and the rate of fertilized is extremely low. It makes population in a degree limit to growing. In addition, aqueous leachates of companion species inhibited and delayed the C. barometz spores germination significantly. In the community that companion species has a great influence the spore germination and new individual gametophyte growth of C. barometz.