Programa de Pós-Graduação em Biologia de Ambientes Aquáticos Continentais, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande, Rio Grande, RS, Brazil.
Programa de Pós-Graduação em Ecologia e Recursos Naturais, Universidade Federal de São Carlos, Rodovia Washington Luís, São Carlos, São Paulo, Brazil.
Environ Toxicol Chem. 2022 Jul;41(7):1675-1685. doi: 10.1002/etc.5339. Epub 2022 Jun 10.
Atrazine is a herbicide widely used in the control of weeds in crops such as corn, sugar cane, and sorghum. It is often found in aquatic environments, where it can potentially endanger nontarget organisms such as microalgae. The present study evaluated atrazine toxicity to seven different species of Chlorophyceae and the tolerance of the species to the herbicide was related to morphological, photosynthetic, chlorophyll-a content and the activity of the glutathione-S-transferase enzyme (GST). The comparison of median effect concentration (EC50) values for growth inhibition indicates higher toxicity of atrazine for Pseudopediastrum boryanum and Desmodesmus communis, intermediate toxicity for Ankistrodesmus densus, Chlamydomonas puliminiorfes, and Raphidocelis subcapitata, and lower toxicity for Kirchneriella lunaris and Ankistrodesmus falcatus (EC50: 38, 42, 66, 103, 248, 1004, and 1585 µg L atrazine, respectively). Principal component analysis (PCA) with algal characteristics suggested that the atrazine-sensitive algae P. boryanum and D. communis were positively associated with photosynthetic levels and negatively associated with GST activity and chlorophyll-a concentration. The PCA also suggested that the atrazine-tolerant algae A. falcatus and K. lunaris were positively associated with morphological parameters, where the larger the cell size, the more tolerant. Although it is difficult to associate a single characteristic of algae as the key factor determining the tolerance to atrazine, results presented in this work indicate that the cell area, the photosynthetic parameters (mainly saturating irradiance), chlorophyll-a content, and the biotransformation by GST in combination may be potential predictors for the differential tolerance of Chlorophyceae species to the herbicide. Environ Toxicol Chem 2022;41:1675-1685. © 2022 SETAC.
莠去津是一种广泛用于玉米、甘蔗和高粱等作物杂草防治的除草剂。它经常在水生环境中被发现，在那里它可能对微藻类等非目标生物构成威胁。本研究评估了莠去津对 7 种不同绿藻物种的毒性，以及物种对除草剂的耐受性与形态、光合作用、叶绿素-a 含量和谷胱甘肽-S-转移酶（GST）活性有关。比较生长抑制的中效浓度（EC50）值表明，莠去津对假蹄形藻和普通小球藻的毒性更高，对密螺旋藻、小环藻、萝卜状膝口藻的毒性中等，对膝口藻和弯角膝口藻的毒性较低（EC50：分别为 38、42、66、103、248、1004 和 1585μg L 莠去津）。用藻类特征进行主成分分析（PCA）表明，对莠去津敏感的藻类 P. boryanum 和 D. communis 与光合作用水平呈正相关，与 GST 活性和叶绿素-a 浓度呈负相关。PCA 还表明，对莠去津耐受的藻类 A. falcatus 和 K. lunaris 与形态参数呈正相关，其中细胞尺寸越大，耐受性越强。虽然很难将藻类的单一特征与决定其对莠去津耐受的关键因素联系起来，但本工作中的结果表明，细胞面积、光合作用参数（主要是饱和辐照度）、叶绿素-a 含量和 GST 的生物转化相结合可能是绿藻物种对除草剂差异耐受的潜在预测因子。环境毒理化学 2022；41:1675-1685。©2022SETAC。
