Phytoremediation of azoxystrobin and its degradation products in soil by P. major L. under cold and salinity stress

Azoxystrobin is a broad-spectrum, systemic and soil-applied fungicide used for crop protection against the four major classes of pathogenic fungi. The use of azoxystrobin use has induced water pollution and ecotoxicological effects upon aquatic organisms, long half-life in soils, as well as heath issues. Such issues may be solved by phytoremediation. Here, we tested the uptake and translocation of azoxystrobin and its degradation products by Plantago major, under cold stress and salt stress. The result demonstrated that azoxystrobin significantly accumulated in P. major roots under salinity conditions more than that in the P. major roots under cold conditions and natural condition within two days of experimental period. In P. major roots and leaves, the chromatograms of HPLC for azoxystrobin and metabolites under natural condition (control) and stressed samples (cold stress and salt stress) show different patterns of metabolism pathways reflecting changes in the degradation products. Azoxystrobin carboxylic acid (AZ-acid) formed by methyl ester hydrolysis was an important route in the roots and the leaves. AZ-pyOH and AZ-benzoic were detected in P. major roots under cold and salt stress, while did not detected in P. major roots under natural condition. In the leaves, AZ-pyOH and AZ-benzoic were detected in all treatments between 4 and 12days of exposure. Shoots of the stressed plants had greater H₂O₂ and proline contents than was observed in the control plants. The level of 100mM NaCl treatment induced significantly higher peroxidase (POD) activity than the non-treated control group. Leaf Chlorophyll contents in the plants at 80 and 100mM NaCl were significantly reduced than was observed in the control plants. I concluded that P. major had a high potential to contribute to remediation of saline-soil contaminated with azoxystrobin.

Phytoremediation of salt-affected soils: a review of processes, applicability, and the impact of climate change

Soil salinization affects 1-10 billion ha worldwide, threatening the agricultural production needed to feed the ever increasing world population. Phytoremediation may be a cost-effective option for the remediation of these soils. This review analyzes the viability of using phytoremediation for salt-affected soils and explores the remedial mechanisms involved. In addition, it specifically addresses the debate over plant indirect (via soil cation exchange enhancement) or direct (via uptake) role in salt remediation. Analysis of experimental data for electrical conductivity (ECe) + sodium adsorption ratio (SAR) reduction and plant salt uptake showed a similar removal efficiency between salt phytoremediation and other treatment options, with the added potential for phytoextraction under non-leaching conditions. A focus is also given on recent studies that indicate potential pathways for increased salt phytoextraction, co-treatment with other contaminants, and phytoremediation applicability for salt flow control. Finally, this work also details the predicted effects of climate change on soil salinization and on treatment options. The synergetic effects of extreme climate events and salinization are a challenging obstacle for future phytoremediation applications, which will require additional and multi-disciplinary research efforts.