Short‐term phytotoxicity in Brassica napus (L.) in response to pre‐emergently applied metazachlor: A microcosm study

Abstract

In accordance with realistic application approaches, a short-term 1-factorial experiment was set up to investigate the phytotoxic impact of pre-emergent application of the chloroacetamide herbicide metazachlor on Brassica napus. In addition to morphological parameters, the underlying processes that ultimately determine the extent of herbicide-induced phytotoxicity (i.e., herbicide metabolization and cellular antioxidant defense) were examined. The present study demonstrated that metazachlor provoked fasciation of the leaves closely after emergence, which might be linked to its mode of action whereby cell division is impaired through the inhibition of very long chain fatty acid synthesis. The increased activities of antioxidative enzymes and metabolites in leaf tissue indicated the presence of reactive oxygen species under the influence of metazachlor. This resulted in oxidative damage in the form of membrane lipid peroxidation. Simultaneously, the increased activity of glutathione S-transferase and the shift in glutathione redox state suggested activation of the detoxification metabolism. This occurred, however, at the expense of growth, with a temporary reduction in plant height and weight after application. The results indicated that metazachlor disappeared within 3 mo to 4 mo after application, which resulted in the recovery of the crop. In conclusion, metazachlor induces phytotoxicity in the short term, either directly through its mode of action or indirectly through the induction of oxidative stress, which resulted in a temporary reduction in growth. Environ Toxicol Chem 2017;36:59-70. © 2016 SETAC.

The Influence of Herbicide Underdosage on the Composition and Diversity of Weeds in Oilseed Rape (Brassica napus L. var. oleifera D.C.) Mediterranean Fields

“…We observed the same finding also in the site of Ussana, where higher doses of pre-emergence treatments (M100, M75, M50) caused phytotoxic effects on oilseed rape by lengthening the phase between sowing and emergence and sowing-flowering and reducing crop growth. The phytoxicity of metazachlor on the oilseed rape crop when applied at labelled dose was also reported by Vercampt et al [83,84].…”

Investigating the eco-friendly extracts of Salvia pratensis L. for sustainable agricultural applications

“…Their primary objective is the eradication of unwanted plant species. The effectiveness of herbicides is in uenced by various factors including plant species, environmental conditions, weather patterns, and the speci c type of herbicide employed [19][20][21]. Sustainable agriculture practices encompass a range of approaches adopted by farmers.…”

Seed germination of common and endangered arable weed species is differently affected by the herbicide metazachlor and its transformation products

“…The combination of hampered cell division and cell expansion might restrain penetration of the seed coat, leading to a delay or failure of seedling emergence (Baskin & Baskin, 2014). Consequently, Vercampt et al (2017) reported a reduction on the germination of oilseed rape seeds exposed to MZ. MZ is very stable in water but also degrades into two major degradation products in soil (henceforth: TPs: metazachlor oxalic acid, MZ‐OA; and metazachlor ethane sulphonic acid, MZ‐ESA; Laue et al, 1996; Lewis et al, 2016).…”