Enhanced atrazine removal by hydrophyte–bacterium associations and in vitro screening of the isolates for their plant growth-promoting potential

Abstract

Emergent hydrophytes Acorus calamus, Typha latifolia, and Phragmites karka and epiphytic root bacteria isolated from their rhizoplanes were exposed to atrazine (5 and 10 mg l) individually and in plant-bacterium combination for 15 days hydroponically. It was observed that A. calamus-Pseudomonas sp. strain, the ACB combination, was best in decontamination, showing 91% and 87% removal of 5 and 10 mg l atrazine. Plant-bacterium association led to significant increase in atrazine decontamination as compared to decontamination by either plant or bacterium alone, indicating a synergistic action of the hydrophytes and isolates which led to enhanced atrazine removal. To the best of our knowledge this is the first report on the potential of plant-bacterium combinations for atrazine decontamination. The isolates showed augmented growth in the presence of plants and were able to alleviate atrazine stress in them. These isolates exhibited plant growth-promoting traits such as auxin, siderophore, Poly(3-hydroxybutyric acid)/succinogycan, ammonia, catalase production and solubilization of inorganic phosphate in vitro. The use of plant-bacterium mutualistic symbiosis for atrazine mitigation is a relatively simple, inexpensive, and clean technique and this phytoremediation-rhizoremediation combination is suggested to be tried on field to establish their potential for clean-up of contaminated sites.

A Review on Recent Treatment Technology for Herbicide Atrazine in Contaminated Environment

“…The degradation rates of atrazine by the strain-wheat and strain-alfalfa systems in 30 days reached to 99.8% and 75.6%, respectively. James et al [104] isolated some Pseudomonas strains from the roots of Acorus calamus, Typha latifolia, and Phragmites karka, and employed them for the combined remediation of atrazine. It showed that the combined system of Acorus calamus and Pseudomonas strains possessed the high removal rate of atrazine, and the combination of microbes-plants could significantly improve the removal of atrazine as compared with the remediation of single plants or microorganisms.…”