College of Plant Science, Jilin University, Changchum-130062; MOA key Laboratory of Plant nutrition, MOE Key laboratory of Soil-Plant Interaction, College of Agricultural Resources and Evironmental Sciences, China Agicultural University, Beijing, 10094; Northeast Institute of Geography and Agricutural Ecology, CAS, Changchum 130012, China
Abstracts, II Chinese Allelopathy Conference, November 3–5, 2005. Agricultural University, Hangzhou, China. Pp. 30, (2005).
A crude aqueous extract from decayed soybean residues (inoculated with soil suspension and incubated for 30 days), was obtained with distilled water. We extracted the crude aqueous extract by ethyl acetate at 2, 7 and 12 pH. No significant allelopathic effect on radicle elongation was observed for the organic phase extracted under basic or neutral media. The organic extract under PH 2 was further eluted sequentially by eight solvents from petroleum ether to methanol with increasing polarity in a silica gel column (20 mm × 100 mm, vacuum). Eight fractions were collected and tested with same bioassay. Our results showed that two fractions were most inhibitory. Another silica gel column (15 mm × 250 mm) was then applied to isolate the mixture of the above two fraction with a solvent mixture of methnol and ethyl acetate as an eluent. The eluates were collected every 50 ml. These eluates were combined into three samples. After assayed with radicle elongation of soybean seedling, the second sample was found most toxic. The analysis with gas chromatography-mass spectrometry (GC-MS) indicated twelve compounds were present in the second sample. We indentified these 12 compounds as: Phenol 2,4-bis (1,1-dimethylethyl), 1-Hexadecene, 1-Octadecene, 1-Octadecene, 9-Hexadecenoic acid, methyl ester, 8-Octadecenoic acid, methyl ester, Hexadecanoic acid and butyl ester. In conclusion, we think these twelve compounds from the soybean residues causes the allelopathic effects.
