Effect of culture and extract solutions of macrophytes on the growth of three common algae

The effects of culture and extract solutions of six macrophytes on the growth of three common phytoplankton were investigated under laboratory conditions. Culture solutions were taken from a Hoagland nutrient solution that contained live plants growing for 7 days and the extract solution was made from a solution with fresh plant pieces immersed in Hoagland nutrient solution for 48 h. The algae were grown in the culture or extract solution for 15 days and the algal density was determined every 2 days. The results showed that the culture solution of the macrophytes both inhibited and stimulated algae growth depending on the macrophytes and the algae. All extract solutions of the macrophytes exhibited a stimulatory effect on the growth of the algae that also varied with the macrophytes and the phytoplankton. The results indicated that culture solutions of macrophytes may be more suitable for the control of algal blooms in eutrophic waters than their extract solutions.