The main chemical compounds in pyrethrum flower extract obtained by supercritical fluid extraction (SFE) were identified by GC-MS. Peak area normalization was used to determine relative percentage content of the compounds. The results showed that the main chemical compounds in pyrethrum flower extract were β-farnesene, β-cubebene, ethyl palmitate and ethyl linoleate, besides six pesticidal active compounds of pyrethrins that were cinerin I, jasmin I, pyrethrin I, cinerinII, jasminIIand pyrethrinII.

Some chemical compounds in petroleum ether extract ofMikania micranthaH.B.K. can strongly influence seedling growth ofPhaseolus radiaus. In this study, we provide evidence that the chemical compounds in active fraction chromatographed on normal phase silica gel columns from petroleum ether extract ofM. micranthahave strong activity to promoteP. radiaustaking root. But meanwhile, these chemical compounds could be inhibitors forP. radiausroot growth. Two main chemical constituents, α-Bisabolol and Eudesma-5,11(13)-dien-8,12-olide, in the active fraction were confirmed by GC-MS analysis.

The pollution characteristics of n-alkanes and polycyclic aromatic hydrocarbons (PAHs) in the typical tree species (Chinese Glossy Privet tree, Camphors tree, Osmanthus tree) in Chengdu city were studied. The distribution and sources of n-alkanes and PAHs in leave samples were discussed. The results showed the carbon number of n-alkanes ranging from nC11 to nC34 of leaves samples in Chengdu City was detected out and the distributions of n-alkanes of selected plant leaves in different sampling sites showed obvious difference. The content of n-alkanes in the east site leave samples was the most abundant, the highest value was 5.2 μg/g while the least was at the north site (0.01μg/g). The content of PAHs in the north site leave samples was the most abundant with the highest value being 242.56 μg/kg while the least was at the central site with the lowest value of 0.11μg/kg. The content of n-alkanes and PAHs in Camphors tree leaves was higher than Osmanthus tree leaves suggesting Camphors tree could better purified the city air.

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X-ray Fluorescence was used to determine the content of 25 inorganic elements in Chengdu dust in this article, and enrichment factor was used to analyze its distribution characteristics and source apportionment. The results showed that Cr was the extremely severe pollutant, with its average concentration of 64.57μg/g, the average enrichment factor coefficient of 477.79, which was more than 10 times higher than background value, suggested it was significantly contributed by the anthropogenic sources. Ca was the heavily polluted element, with its concentration of 7.71μg/g in average, and the average enrichment factor coefficient being 12.26, which was more than 10 times of the background value, showed it was also affected by the anthropogenic sources. The enrichment factor coefficient of Na, As, Co, Cu, Mn, Ni, Pb, Se, V, Zn, K, Mg, Br, Cs was about 1 in average, illustrated that they were not obviously affected by the man-made pollution.