Multiple endpoints of polyethylene microplastics toxicity in vascular plants of freshwater ecosystems: A study involving Salvinia auriculata (Salviniaceae)

More recently, the number of studies on the impacts of microplastics (MPs) on plants has drawn attention considerably. However, many of these studies focused on terrestrial plants, with vascular plants from freshwater ecosystems being little studied. Thus, we aimed to evaluate the possible effects of exposure of Salvinia auriculata, for 28 days, to different concentrations of polyethylene MPs (PE MPs – diameter: 35.46 ± 18.17 µm) (2.7 ×108 and 8.1 ×108 particles/m3), using different biomarkers. Our data indicated that exposure to PE MPs caused alterations in plant growth/development (inferred by the lower floating frond number, “root” length, and the number of “roots”), as well as lower dispersion of individuals in the experimental units. Plants exposed to PE MPs also showed lower epidermal thickness (abaxial leaf face) and a longer length of the central leaf vein and vascular bundle area. Ultrastructural analyses of S. auriculata exposed to MPs revealed rupture of some epidermal cells and trichomes on the adaxial and abaxial, leaf necrosis, and chlorosis. In the “roots”, we observed dehydrated filamentous structures with evident deformations in plants exposed to the pollutants. Both on the abaxial leaf face and on the “roots”, the adherence of PE MPs was observed. Furthermore, exposure to PE MPs induced lower chlorophyll content, cell membrane damage, and redox imbalance, marked by reduced catalase and superoxide dismutase activity and increased production of reactive oxygen and nitrogen species as well as malondialdehyde. However, in general, we did not observe the dose-response effect for the evaluated biomarkers. The values of the integrated biomarker response index, the principal component analysis (PCA) results and the hierarchical clustering analysis confirmed the similarity between the responses of plants exposed to different PE MPs concentrations. Therefore, our study sheds light on how PE MPs can affect S. auriculata and reinforces that putting these pollutants in freshwater environments might be hazardous from an ecotoxicological point of view.

Fil: Gomes, Alex Rodrigues. Goiano Federal Institute; Brasil

Fil: Freitas, Ítalo Nascimento. Goiano Federal Institute; Brasil. University of Uberlándia; Brasil

Fil: da Luz, Thiarlen Marinho. Goiano Federal Institute; Brasil

Fil: Guimarães, Abraão Tiago Batista. Goiano Federal Institute; Brasil

Fil: Araújo, Amanda Pereira da Costa. Universidade Federal de Goiás; Brasil

Fil: Kamaraj, Chinnaperumal. Interdisciplinary Institute Of Indian System Of Medicin; India

Fil: Rahman, Md. Mostafizur. Jahangirnagar University; Bangladesh

Fil: Islam, Abu Reza Md. Towfiqul. Begum Rokeya University; Bangladesh

Fil: Arias, Andres Hugo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina

Fil: Barbosa da Silva, Fábia. Goiano Federal Institute; Brasil. Universidade Federal de Goiás; Brasil

Fil: Karthi, Sengodan. Manonmaniam Sundaranar University; India

Fil: Cruz Santiago, Omar. Universidad Autónoma de San Luis Potosí; México

Fil: Silva, Fabiano Guimarães. Goiano Federal Institute; Brasil. Universidade Federal de Goiás; Brasil

Fil: Malafaia, Guilherme. Goiano Federal Institute; Brasil. Federal University of Uberlándia; Brasil. Universidad Autónoma de San Luis Potosí; México. Universidade Federal de Goiás; Brasil