Department of Biology & CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal.
Department of Biology, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal.
Ecotoxicology. 2020 May;29(4):444-458. doi: 10.1007/s10646-020-02184-6. Epub 2020 Mar 18.
Soils can be contaminated with substances arising from anthropogenic sources, but also with natural bioactive compounds produced by plants, such as terpenes and flavonoids. While terpenes and flavonoids have received much less attention from research studies than metals, the effects that phytocompounds can have on soil organisms such as beneficial microorganisms should not be neglected. Herein we report the sole and combined exposure of Rhizobium to cadmium, to the monoterpene alpha-pinene and to the flavanol quercetin. A range of environmentally relevant concentrations of the phytocompounds was tested. Physiological (growth, protein content and intracellular Cd concentration), oxidative damage (lipid peroxidation, protein carbonylation) and antioxidant mechanisms (superoxide dismutase, catalase, glutathione, glutathione-S-transferases, protein electrophoretic profiles) were assessed. Results suggest that exposure to both phytocompounds do not influence Rhizobium growth, but for combined exposure to phytocompounds and Cd, different responses are observed. At low concentrations, phytocompounds seem to relieve the stress imposed by Cd by increasing antioxidant responses, but at high concentrations this advantage is lost and membrane damage may even be exacerbated. Thus, the presence of bioactive phytocompounds in soil may influence the tolerance of microorganisms to persistent toxicants, and may change their impact on the environment.
土壤可能受到人为来源物质的污染，也可能受到植物产生的天然生物活性化合物的污染，如萜烯和类黄酮。虽然萜烯和类黄酮在研究中受到的关注比金属少得多，但植物化合物对土壤生物（如有益微生物）可能产生的影响不应被忽视。本文报道了根瘤菌单独和联合暴露于镉、单萜α-蒎烯和类黄酮槲皮素的情况。测试了一系列与环境相关的植物化合物浓度。评估了生理（生长、蛋白质含量和细胞内 Cd 浓度）、氧化损伤（脂质过氧化、蛋白质羰基化）和抗氧化机制（超氧化物歧化酶、过氧化氢酶、谷胱甘肽、谷胱甘肽-S-转移酶、蛋白质电泳图谱）。结果表明，暴露于两种植物化合物不会影响根瘤菌的生长，但对于植物化合物和 Cd 的联合暴露，观察到不同的反应。在低浓度下，植物化合物似乎通过增加抗氧化反应来缓解 Cd 带来的压力，但在高浓度下，这种优势丧失，膜损伤甚至可能加剧。因此，土壤中存在生物活性植物化合物可能会影响微生物对持久性有毒物质的耐受性，并可能改变它们对环境的影响。
