AUTHOR=Asaeda Takashi , Senavirathna M. D. H. Jayasanka , Vamsi Krishna Lekkala 

TITLE=Evaluation of Habitat Preferences of Invasive Macrophyte Egeria densa in Different Channel Slopes Using Hydrogen Peroxide as an Indicator

JOURNAL=Frontiers in Plant Science

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2020.00422

DOI=10.3389/fpls.2020.00422

ISSN=1664-462X

ABSTRACT=<p><italic>Egeria densa</italic> is an often-found invasive species in Japan, which has spread widely in the past two decades in rivers where no macrophytes had previously been found. As a result, these ecosystems have now become dominated by <italic>E</italic>. <italic>densa</italic>. The habitat preference for <italic>E</italic>. <italic>densa</italic> colony formation was investigated using the tissue concentrations of hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>: a reactive oxygen species) under varying conditions in rivers and laboratory conditions. The empirical equations that can describe the macrophyte tissue H<sub>2</sub>O<sub>2</sub> formation under various velocity and light conditions were produced. The H<sub>2</sub>O<sub>2</sub> concentrations of dark-adapted plants are proportional to the flow velocity, and the surplus H<sub>2</sub>O<sub>2</sub> concentration in the light-exposed condition corresponded to the photosystems produced H<sub>2</sub>O<sub>2</sub>. When the H<sub>2</sub>O<sub>2</sub> concentration exceeds 16 μmol/gFW, plant tissue starts to deteriorate, and biomass declines, indicating the critical values required for long-term survival of the plant. The empirically obtained relationships between flow velocity or light intensity and the analysis of H<sub>2</sub>O<sub>2</sub> concentration for different slopes and depths of channels found that the H<sub>2</sub>O<sub>2</sub> value exceeds the critical H<sub>2</sub>O<sub>2</sub> concentration in channels with above 1/100 at around 0.6 m depth. This agrees with the observed results where colonies were not found in channels with slopes exceeding 1/100, and biomass concentration was the largest at depths of 0.6 to 0.8 m. H<sub>2</sub>O<sub>2</sub> concentration is quite applicable to understanding the macrophyte condition in various kinds of macrophyte management.</p>