Phytotoxicity assessment of atrazine on growth and physiology of three emergent plants

The emergent plants Acorus calamus , Lythrum salicaria , and Scirpus tabernaemontani were exposed to atrazine for 15, 30, 45, and 60 days in a hydroponic system. Effects were evaluated investigating plant growth, chlorophyll (Chl) content, peroxidase (POD) activity, and malondialdehyde (MDA) content. Results showed that selected plants survived in culture solution with atrazine ≤8 mg L −1 , but relative growth rates decreased significantly in the first 15-day exposure. Chl a content decreased, but MDA increased with increasing atrazine concentration. S. tabernaemontani was the most insensitive species, followed by A. calamus and L.salicaria . The growth indicators exhibited significant changes in the early stage of atrazine exposure; subsequently, the negative impacts weakened and disappeared. Plant growth may be more representative of emergent plant fitness than physiological endpoints in toxicity assessment of herbicides to emergent plants.