The phaeophyte <em>Hizikia fusiformis</em> extracts suppress rhizoid and blade formation in seaweeds

Abstract

Background: Plants, including marine algae, produce allelochemicals that influence the growth, survival, and reproduction of other organisms. Questions: To identify natural algicidal or antifouling allelochemicals, we screened 18 common seaweed extracts for suppression of rhizoid and blade production in a convenient Porphyra suborbiculata monospore assay. Species study and data description: Addition of extract from the most potent phaeophyte, Hizikia fusiformis, suppressed rhizoid formation, rhizoid number, rhizoid length, blade formation, and blade length. Study site and dates: Seaweed thalli for methanol extraction were collected on the coast of Korea from October 2012 to July 2015. Methods: Extracts were tested using the P. suborbiculata monospore assay system. Results: The 50 % suppression doses were 15 µg ml-1 for rhizoid formation, 2.4 µg ml-1 for rhizoid number, 13 µg ml-1 for rhizoid length, 6 µg ml-1 for blade formation, and 11 µg ml-1 for blade length. The H. fusiformis extract also suppressed rhizoid and blade production in leafy green (Ulva pertusa) and brown (Undaria pinnatifida and Ecklonia cava) seaweed spores, as well as suppressing diatom settlement. Conclusions: The allelochemicals that suppressed or eliminated competing seaweed species may be efficacious for new seaweed control technologies, including the development of antifouling or algicidal agents based on natural products.

Keywords

• Allelochemicals
• Hizikia fusiformis
• monospore
• rhizoid
• suppression