Allelopathy Of Several Plant Species To Chinese-fir

Chinese fir is one of the most important afforestation tree in south China, but continuous plantation can cause site deterioration and productivity drops which partly results from autotoxicity. To solve this problem, aqueous extracts method is used in previous researches. However, in natural conditions, the allelochemicals spread into the environment by various ways, hi view of above, we think adoption of aqueous extract method only can't reflect the nature objectively. So, in this paper, organic solvent extract and supercritical fluid technology, etc methods were used to explore the atuotoxication of rhizosphere soil and root extract of Chinese fir further.Continuous plantation obstacle and low benefits of Chinese fir plantation ecosystem caused by long term pure plantation cultivation can be improved through mixed afforestation and compound forestry with agriculture. But research on the interspecific biochemical relationship between Chinese fir and other plants mixed with it is still very poor, hi the view of this, allelopathy ofSchima superba, accompanied with Chinese fir, rhizosphere soil organic solvent extract and roots supercritical fluid extract on Chinese fir are researched in this paper, and allelopathy of leaves extract of several traditional Chinese herbs with economic value on Chinese fir is studied preliminarily through supercritical fluid extract. The results showed:(1) Rhizosphere soil extract of Chinese fir by the mixed solvent of acetone: ethyl acetate (1:1) inhibited Chinese fir seeds germinated index each. 200mg/kg extract had the strongest inhibitory effects than 100mg/kg' and 50mg/kg'. The influence intensity of 200mg/kg extract on absolute germination rate, absolute germination power and radicle elongation of Chinese fir seeds, decreased by 32.19%, 40.27% and 39.05% respectively compared with alcohol control', decreased by 12.69%, 45.45% and 23.81% respectively compared with 50mg/kg'.(2) Rhizosphere soil extract ofSchima superba by the mixed solvent of acetone: ethyl acetate (1:1) have stimulating effects on absolute germination rate and absolute germination power and inhibitory effects on radicle elongation of Chinese fir seeds in different level. 200mg/kg extract had the strongest advanced effects than 100mg/kg' and 50mg/kg'. The influence intensity of 200mg/kg extract on absolute germination rate and absolute germination power of Chinese fir seeds, raised by 8.69% and 9.02% respectively compared with alcohol control', but radicle elongation, decreased 11.43% compared with alcohol control'.(3) Root extract of Chinese fir by supercritical fluid extract technology l(only CO2 as entrainer, the following is the same) and fluid 2 (after adding the entrainer ethanol, the following is the same) at different parameter inhibited the germination summit and each germination index at different level. The bioassay revealed that except parameter 1, 7 and 8, the extract of supercritical fluid one had inhibitory effects on most germination index and the extracts of supercritical fluid 2 had inhibitory effects on fresh weight and dry weight of seeds at each parameter condition and the other parameters of both extracts had inhibitory effects on individual seeds; the effects on germination summit showed, the germinationsummit of treatment with 100mg/kg at parameter 3 and 7 of supercritical fluid 1 appeared latest; at parameter 3 and 6, Chinese fir germination summit treated with 50mg/kg extracts appeared latest; at other parameters, germination summit appeared latest at 200mg/kg.(4) Schima superba root extracts from supercritical fluid under orthogonal experiment at each parameter conditions affected the Chinese fir seeds germination differently. Bioassay results showed: compared with alcohol control, under the condition of parameter 1,5,8, root extracts stimulated the absolute germination rate, germination potential, radicle growth, but under condition of 3, 6,7, extracts inhibited all index except germination potential, extract at parameter 2 only stimulated the absolute germinat...