Inhibition of dinoflagellate growth by extracts of barley straw (Hordeum vulgare)

Growth of dinoflagellates representing three orders, the Gymnodiniales, Peridiniales, and the Prorocentrales was examined following treatment with barley straw extract. Selected dinoflagellate taxa showed growth responses similar to those reported for freshwater algae including: inhibition (Gyrodinium galatheanum, Gymnodinium sanguineum, Heterocapsa triquetra and H. pygmaea); stimulation (Gyrodinium instriatum, Prorocentrum minimum and P. micans); and no effect (Gyrodinium estuariale, G. uncatenum, Ceratium furca, Peridinium sp.). Although barley straw extracts do not appear to have value as a universal management tool for dinoflagellates, they may have potential in management of specific taxa and possibly taxonomic groups.