THE TOXIC EFFECTS AND DAMAGE MECHANISMS OF WATER EXTRACT OF HYDROCOTYLE AND ACORUS CALAMUS ON POMACEA CANALICULATA

Two aquatic plants, Hydrocotyle and Acorus calamus, were utilized in a study focusing on biological control of Pomacea canaliculatas. The research involved poisoning experiments using extracts of varying concentrations (0, 0.10, 0.20, 0.30, 0.40, and 0.50 mg/mL) and investigated their respective poisoning mechanisms. Results indicated a stronger poisoning effect on Pomacea canaliculatas in the Hydrocotyle group compared to the Acorus calamus group. Sublethal concentrations for the Hydrocotyle group were found to be 0.113 mg/mL (LC₂₅)_, 0.220 mg/mL (LC₅₀), 0.326 mg/mL (LC₇₅), while for Acorus calamus, they were 0.444 mg/mL (LC₂₅), 0.587 mg/mL (LC₅₀), and 0.730 mg/mL (LC₇₅). Pomacea canaliculatas treated with Hydrocotyle and Acorus calamus displayed significantly lower oxygen consumption rate and ammonia excretion rate compared to the control group (P<0.05), along with a reduced oxygen-to-nitrogen ratio. Additionally, after 48h of treatment at sublethal concentrations, differences were observed in total protein content (TP), superoxide dismutase (T-SOD) activity, and acetylcholinesterase (AChE) activity compared to the control group (P<0.05). Morphological changes such as shrinkage and erosive floc accumulation on the head and feet of snails, as well as shriveled, dehydrated liver tissue with loose texture and surface tissue detachment, were noted in the treatment group. Overall, Hydrocotyle and Acorus calamus exhibited evident poisoning effects on Pomacea canaliculatas.