Author(s): Takashi Asaeda; Junichi Akimoto
Linked Author(s): Takashi Asaeda
Keywords: Riparian vegetation colonization elevation hydrogen peroxide oxidative stress
Abstract: The colonization level of riparian plants is species-specific and depends on soil moisture. Hydrogen peroxide (H2O2), generated at the thylakoid membrane during the photosynthesis process, deteriorates the photosynthetic apparatus and inhibits species colonization. The H2O2 concentrations in the leaves of Phragmites and Miscanthus species were observed as a function of soil moisture. For Phragmites, H2O2 concentration uniquely declined with increasing soil moisture. In contrast, Miscanthus exhibited an initial decline in H2O2 concentration, followed by an increase as soil moisture levels rose. Both species maintained sufficient chlorophyll-a concentrations in their leaves. Under conditions of low water content in leaves or soil moisture, stomata close, inhibiting carbon dioxide (CO2) inflow, which limits carbohydrate synthesis and electron consumption. Miscanthus, with its greater ability to absorb water from underground soil, keeps its stomata open even at relatively low soil moisture levels. This trait enables it to consume electrons generated by solar energy, reducing H2O2 concentration. However, at higher soil moisture levels, increased water content generates more electrons, leading to a rise in H2O2 concentration. As a result, Miscanthus needs to colonize areas with optimal soil moisture at higher elevations. Conversely, Phragmites, with its lower water absorption capacity, tends to close its stomata under low water content conditions. This inhibits electron consumption, maintaining higher levels of H2O2 concentration at low soil moisture sites. Consequently, Phragmites is better suited to colonizing areas close to the shoreline.
Year: 2025