Allelopathy Inhibitory Effects of Hydrodictyon reticulatum on Chlorella pyrenoidosa under Co-Culture and Liquor-Cultured Conditions

Eutrophication has become increasingly serious in recent years, which severely impairs the aquatic ecosystem. Applying environmentally-friendly methods to effectively control the growth of algae and avoid eutrophication has been proved to be a promising way. Thus, the potential of Hydrodictyon reticulatum on eutrophication control was studied in this research. The allelopathy inhibitory effects of H. reticulatum on the growth of Chlorella pyrenoidosa were investigated under both co-culture and liquor-cultured conditions. The biomass and chlorophyll a content of C. pyrenoidosa were determined with time during the experimental period. Nitrogen and phosphorus removal capacities of H. reticulatum were also examined. Results showed that the growth of C. pyrenoidosa was obviously inhibited under both co-culture and liquor-cultured conditions, and the “Hormesis effect” was patently observed. The strength of allelopathy inhibitory effect depended on the relative biomass between H. reticulatum and C. pyrenoidosa. The allelopathy inhibitory effect of H. reticulatum on C. pyrenoidosa under co-culture condition was stronger than that under liquor-cultured condition. The decrease speeds of nitrogen and phosphorus concentrations were in direct proportion to the concentration of H. reticulatum.