Faculty of Engineering, Tokyo University of Agriculture and Technology, Naka, Koganei, Tokyo 184–8588, Japan. E-Mail: nakai@cc.tuat.ac.jp
*Correspondence author.
1Public Works Research Centre, Tailonku, Tokyo 110–0016, Japan.
An assay of “rotting-reed solution (RRS)” against Phormidium tenue and Microcystis aeruginosa, inhibited the growth of both cyanobacteria and the growth inhibitory effect of RRS was correlated with its DOC (dissolved organic carbon) concentration. P. tenue was more sensitive to the allelopathic effect. Reed collected in October was most inhibitory to P. tenue growth than that collected from May to November. Reed collected in April and December had no effect. DOC concentration of RRS changed seasonally. GC/MS analyses of RRS extracts showed the release of eight phenols (p-coumaric, ferulic, vanilic, sinapic, syringic, caffeic, protocatechuic, and gallic acids) and four fatty acids (myristic, palmitic, pelargonic, and stearic acids). Four phenols (sinapic, syringic, caffeic, and gallic acids) and the fatty acid pelargonic acid, inhibited the growth of both cyanobacteria, whereas, inhibitory effects of p-coumaric, ferulic, vanillic and myristic acid were species-specific. Ferulic, stearic, and palmitic acids did not show any effect.
Allelopathy, cyanobacteria, fatty acid, growth inhibition, Microcystis aeruginosa, phenol, Phormidium, tenue, Phragmites australis, reed
