Photosynthetic Physiological And Biochemical Characteristics Of Dicrarcopteris Dichotoma In Three Different Communities Of Qiandao Lake

The dicranopteris pedata is widely distributed in tropical and temperate areas,which is intensively distributed in the extensive subtropics hilly areas such as the middle and lower reaches of Yangtze River,south of the Yangtze River and southwest areas.The dicranopteris pedata in the substratumr of forest community often constitutes an "ecological screen",which has a selective function in the process of forest regeneration,determining the spatial distribution pattern of forest regeneration of tree species.In the spring,summer and autumn of 2017,choosing three biotopes including hydrophobe scrub-grassland,single excellent communities of masson pine and the substratum of evergreen broad-leaved forest community in Qiandaohu National Forest Park Laoshan Forest Farm,to measure the photoresponse progress and chlorophyll fluorescence parameters of the potted dicranopteris pedata,at the same time,to measure microclimatic factors and physical and chemical properties of the potted dicranopteris pedata,to discusse the growth and development characteristics of potted dicranopteris pedata in different biotopes.By means of measurement and research,to further reveale the relationship between the characteristics of growth and development and distribution of dicranopteris pedata and the biotopes in different communities,which provides theoretical basis for the applying of undergrowth ground vegetation and the forest regeneration of tree species and community succession in subtropics hilly areas.The research results show that:1)The change order of the magnitude of the net photosynthetic rate(Pn)of dicranopteris pedata in spring and autumn under different biotope conditions is that single excellent communities of masson pine>evergreen broad-leaved forest community>hydrophobe scrub-grassland;in summer,single excellent communities of masson pine>hydrophobe scrub-grassland >evergreen broad-leaved forest community,the dicranopteris pedata has strong light adaptation,but hydrophobe scrub-grassland at summer high temperature is not suitable for growth.2)There is no significant difference in fluorescence induction curve between single excellent communities of masson pine and the mixed undergrowth of evergreen broad-leaved forest(p>0.05),but obviously higher than hydrophobe scrub-grassland(p<0.05).The fluorescence intensity of dicranopteris pedata in single excellent communities of masson pine is the greatest,and the dicranopteris pedata is exposed to higher stress in the mixed undergrowth of evergreen broad-leaved forest.The dicranopteris pedata through increasing the reaction core density(RC/CSo),maximum photochemical efficiency after dark reaction(?Po),electron transfer efficiency(?o)and performance index(PIABS),to reduce electron transfer quantum yield(?Eo),the quantum ratio of heat dissipation(?Do)and specific activity parameter(ABS/RC?TRo/RC?ETo/RC)to adapt to low light biotopes.3)The effect of hydrophobe scrub-grassland on membrane lipid peroxidation of dicranopteris pedata is more serious than that of low light;in the single excellent communities of masson pine and the substratum of evergreen broad-leaved forest community,the antioxidant enzyme activity of dicranopteris pedata is higher,in addition,the increase of POD and CAT activity has compensation and coordinationfor to a certain extent on the decrease of SOD activity.The increase of light intensity is one of the important factors resulting in the synthesis and accumulation of soluble protein in the leaves of potted dicranopteris pedata.Therefore,the physiological parameters of photosynthesis of dicranopteris pedata in the substratum of single excellent communities of masson pine have significant advantages,it is believed that appropriate light intensity becomes the main ecological factor that restricts photosynthetic response and fluorescence parameters of dicranopteris pedata.