Studies On Flora Characteristic Of Pteridophyte And Its Resource Utilization Of Canyon Habitats In Mengdong River Scenic Area

Mengdong River Scenic Area which located in Yongshun County in the west of Hunan Province is situated in Youshui River in the middle of Wuling Mountain and has typical physiognomy of canyon. The flora characteristic of Pteridophyte and its resource utilization of canyon habitats in Mengdong River Scenic Area were analyzed in the paper through the field investigation and data analysis, the study of the extraction of flavonoid or polysaccharide from Drynaria roosii Nakaike as well as the effects of the extracts on bacteria from Lygodium japonicum (Thunb.) Sw or Woodwardia unigemmata (Makino) Nakai, the main results are as follows:1. There are 71 species of pteridophyte which belong to 37 genera and 21 families respectively in the Canyon of Mengdong River. The dominant families are Dryopteridaceae, Polypodiaceae, Thelypteridaceae, Aspleniaccae, etc, but the number of species is small within genera and families. Most of them are autochthonal, and others are lithophytes or adnascent, however no aquatic types in this area. The main characteristics of the flora of pteridophyte are dominant eastern Asian elements, next comes tropical elements, and then temperate elements. This flora of pteridophyte has close relationship with the floras of tropical Asian, South and West of China, South of China and Japan. Thus it could be grouped into Flora of Polysticho-Dryopteris.2. Through the comparison with other floras of pteridophyte which in Wuling Mountain and canyon (or valley), it was found that this flora is similar to Dehang Scenic Area and Jiaomuxi valley forest, and then to Xiaoxi Nature Reserve and Hupingshan Nature Reserve. This flora may be a representative in Wuling Mountain area.3. Extraction of flavonoid in the rhizome of D. fortumei by microwave extraction and polysaccharide in the rhizome by ultrasonic extraction was conducted respectively. The optimum conditions for flavonoid extraction are as follows:ethanol concentration 40%, solid-liquid ratio 1:20 (g:mL), microwave power 325 W, extraction time 40 s, and microwave power has the most significant effects on extraction rate; the optimum conditions for polysaccharide extraction are as follows:temperature 70℃, solid-liquid ratio 1:30 (g:mL), ultrasonic power 500 W, extraction time 35 min, under these conditions, the extraction rate of 0.583% was obtained.4. The extracts from L. japonicum or W. unigemmata which are stable under conditions of strong acid, high temperature and ultraviolet light have good inhibitory effects on bacteria.