Allelopathic inhibitory effect on the growth of microcystis aeruginosa by improved ultrasonic-cellulase extract of Vallisneria

The unique and efficient characteristics of allelopathy in submerged plants make it an environmentally friendly method to control harmful algal blooms. Increased research focus has been placed on the improved allelochemical extraction methods of submerged plants because of their cost-utility relationships. In this study, the growth inhibition effect of Vallisneria extract on Microcystis aeruginosa (M. aeruginosa) cells through the combination of enzyme and ultrasonic-assisted extraction method was analyzed. By establishing a co-cultivation experiment, the growth indicators, photosynthetic system, and oxidative stress system of M. aeruginosa were determined. The reactive oxygen species (ROS) and superoxide dismutase (SOD) activity, as well as the catalase (CAT) and Malondialdehyde (MDA) levels of algal cells were found to have increased significantly after co-cultivation, which indicated that the Vallisneria ultrasonic-cellulase extract could induce oxidative stress in Microcystis aeruginosa cells. The Vallisneria extract could promote at low concentrations and inhibit at high concentrations on the growth of Microcystis aeruginosa. The effective suppression of growth of algae cells with the extract was observed at 5 g/L (fresh weight). The results showed that the Vallisneria ultrasonic-cellulase extract had a significant inhibitory effect on M. aeruginosa, making the effective ingredients a useful reference for algae inhibitors.