Effects of 2,4-D, glyphosate and paraquat on growth, photosynthesis and chlorophyll–a synthesis of Scenedesmus quadricauda Berb 614

• Published in: Chemosphere (Oxford) Vol. 41; no. 1; pp. 177 - 182
• Main Author: Wong, P.K.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Oxford Elsevier Ltd 01.07.2000; Elsevier
• Subjects: 2,4-D; 2,4-Dichlorophenoxyacetic Acid - adverse effects; Analysis methods; Animal, plant and microbial ecology; Applied ecology; Applied sciences; Biological and medical sciences; biosynthesis; chlorophyll; Chlorophyll - biosynthesis; Chlorophyll A; Chlorophyta - drug effects; Chlorophyta - physiology; Dose-Response Relationship, Drug; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on plants and fungi; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Glycine - adverse effects; Glycine - analogs & derivatives; Glyphosate; growth rate; Herbicides - adverse effects; Hong Kong; indicator species; Natural water pollution; paraquat; Paraquat - adverse effects; photosynthesis; Photosynthesis - drug effects; Pollution; Scenedesmus quadricauda; toxicity; Water Pollutants, Chemical - adverse effects; water pollution; Water treatment and pollution; China, People's Rep., Hong Kong; 2,4-D; Growth; Algae; Pesticides; Biological indicator; Organic phosphonate; Biosynthesis; Chlorophyceae; Glyphosate; Herbicide; Contamination; Chlorophyll a; Quaternary ammonium compound; Freshwater environment; Phytotoxicity; Chlorophyta; Paraquat; Water pollution; Photosynthesis; Thallophyta; Scenedesmus quadricauda
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/S0045-6535(99)00408-7

The effects of 2,4-D, glyphosate and paraquat on growth, photosynthesis and chlorophyll- a synthesis by a freshwater green alga, Scenedesmus quadricauda Berb 614, were determined. These herbicides are the most often used in Hong Kong. Within the concentration range 0.02–200 mg/l, paraquat was more toxic than glyphosate and 2,4-D to the growth, photosynthesis and chlorophyll- a synthesis. The presence of 0.02, 0.2 or 2 mg/l of 2,4-D was not toxic to the alga. Algal growth, photosynthesis and chlorophyll- a synthesis were stimulated by the presence of low concentrations (0.02 or 0.2 and 0.02 mg/l, respectively) of 2,4-D and glyphosate. The presence of 0.02 or 0.2 mg/l of paraquat, 2 mg/l of glyphosate or 20 mg/l of 2,4-D was significantly inhibitory to the three test parameters, whereas the presence of 2 or more mg/l of paraquat, 20 or more mg/l of glyphosate or 200 mg/l of 2,4-D completely inhibited algal growth, photosynthesis and chlorophyll- a synthesis. The use of the alga as a bio-indicator of herbicide contamination in freshwater environment was discussed.