Spatial pattern of foliar hydrogen peroxide concentration and its implication in riparian vegetation management

Riparian vegetation is constantly subjected to environmental stresses and reactive oxygen species (ROS) are generated in the plant tissue due to the stress. The study assessed the environmental stress in vegetation by quantifying the foliar hydrogen peroxide (H2O2) concentration across the elevation gradient of riparian zone of Hii River in Japan. Leaf samples of four common riparian species, Phragmites australis, Phragmites karka, Juglans mandshurica, and Salix pierotii, were used for the investigation. Leaf samples were collected at different elevations along the river. The results indicated that foliar H2O2 concentrations of P. australis, P. karka, and S. pierotii decrease with lower elevations indicating low levels of stress due to higher availability of soil moisture. However, J. mandshurica showed the opposite trend. This tree species had a higher concentration of foliar H2O2 at lower elevations. J. mandshurica had a higher hydrogen peroxide content with decreasing soil nitrogen concentration, indicating that J. mandshurica prefer fertile soil, especially with regard to the nitrogen content. The results clearly indicate that for J. mandshurica, the preferential location and stress was mainly based on soil nutrient availability. Our findings reveal that hydrogen peroxide is a very efficient and reliable index for quantifying environmental stress for vegetation management.