コンブ科褐藻数種のエゾアワビに対する摂食阻害活性

抄録

Feeding-deterrent activities of the methanol extracts from the brown algae of the family Laminariaceae, Ecklonia cava, E. kurome, Laminaria japonica, L. religiosa, L. angustata, and L. angustata var. longissima, were tested on the ezo-abalone Haliotis discus hannai by a bioaasay with the cellulose plate method. Three phlorotannin-rich fractions from the methanol extracts of E. cava and E. kurome, which are perennial algae, showed potent feeding-deterrent activity as in the cases of E. stolonifera and Eisenia bicyclis. On the other hand, none of the fractions from the methanol extracts of four Laminaria species, which are annual algae, showed any significant feeding-deterrent activity as in the cases of Eckloniopsis radicosa. Among four perennial species, the feeding-deterrent activities are, in order of effectiveness, E. stolonifera, E. kurome, E. cava, and Eisenia bicyclis, this being in reciprocal proportion to their size. It was concluded that laminariaceous algae have a chemical defense mechanism against marine herbivores, which adaptively depends on the rate of algal growth and size.