Phloem Redistribution of Pesticide Phenamacril in Plants Followed by Extensive Biotransformation

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农药氰烯菌酯在植物韧皮部的重新分布及其广泛的生物转化

关键词：

来源：

Environmental Science & Technology Letters 期刊

全文链接：

//agri.nais.net.cn/topic/downloadFile/dbf39b69-b243-4421-b987-a69414dbba50

来源地址：

https://pubs.acs.org/doi/epdf/10.1021/acs.estlett.3c00862?ref=article_openPDF

资源所属：

茶学研究专题

类型：

学术文献

语种：

英语

原文发布日期：

2023-12-18

摘要：

Here, we evaluated the uptake and biotransformation mechanism of the systemic fungicide phenamacril in hydroponic/soil–plant systems. Phenamacril was preferentially accumulated in shoots with the translocation factor up to 3.5 (or 6.9) in wheat (or rice) during 144 h of the uptake kinetic experiment. Apart from upward xylem translocation, phenamacril could also be redistributed from shoots to roots (0.4%) through phloem transport and then released into the rhizosphere surrounding solution (1.7%) through plant excretion via a split-root experiment. Then, 76.4% (or 70.4%) of phenamacril was transformed to 14 (or 12) metabolites in hydroponic-wheat (or hydroponic-rice) systems after 28 days of exposure, with nine of them first identified based on nontarget analysis. The proposed metabolic pathways included hydroxylation, hydrolysis, isomerization, dehydrogenation, deamination, dehydration, decarboxylation, reduction, and conjugation reactions, which were modulated by genes overexpression of metabolic enzymes (e.g., cytochrome P450). Notably, metabolite M-157 was predicted to be more persistent in environments and more toxic to rats and aquatic organisms than phenamacril by theoretical calculation. This study highlights that phloem transport and plant excretion may result in cycling chemical contamination, and the transformation products may possess elevated toxicities, thus should be considered in estimating the contamination of pesticides in crops and environments.