Allelopathic activity of Myriophyllum spicatum: a quantitative review

Abstract

Over the years, a lot of research has been done on possible allelopathic abilities of Myriophyllum spicatum. Although some reviews have been written in the past, none of them actually analyzed data from multiple studies in a quantitative way. This can give more insight in the overall patterns these combined data might generate and can help by giving new insights on which future research should focus on. This was done by collecting quantitative data from a literature search and analyzing possible patterns in the data. The main results were that M. spicatum shows a general significant inhibitory effect on algal growth in both coexistence experiments with fresh macrophyte biomass and in experiments where exudates of the macrophyte were added to algae communities. Also, cyanobacteria were mostly affected by M. spicatum presence compared to green algae and diatoms. Three allelopathic substances excreted by M. spicatum (pyrogallic, gallic and elagic acid) were confirmed to inhibit algal growth. It is recommended to focus future research on the excretion rates of allelopathic substances by M. spicatum and other macrophytes to be better able to make realistic estimations on allelopathic interactions of M. spicatum and other macrophytes with algal communities which can be related to natural situations.