Review of the toxic effect of microplastics on terrestrial and aquatic plants

Highlights: • Physical injury of MPs to plants correlated to their type, size and oxygen groups. • Secondary risk including additives and MP-derived products were reviewed. • The seeds and rhizomes of plant are more sensitive to MPs. • Toxicity difference of MPs on terrestrial and aquatic plants was compared. As a new pollutant, microplastics (MPs) exhibited more and more significant influence on the organisms in the environment. Especially, the effects on the growth and development of plants by MPs attracted wide attentions in recent period. In the review article, we summarized the important influences of MPs on terrestrial and aquatic plants. The properties, including type, size and oxygen-containing group of MPs on their physical injures toward plants were critically reviewed, which were significantly correlated to the toxicity to plants. The secondary risks of MPs including the additives and MP-derived organic products and the adsorbed environmental pollutants to plants were clearly revealed. The hydrophobic organic pollutants released from MPs showed significant chemical effects on the plants. We also outlined the effects of MPs to the various regions (e.g. the seed and rhizome) of plants and compared the toxic difference of MPs on terrestrial and aquatic plants. Generally, the seed and rhizome of plants were susceptible to MPs, and the effects of MPs on terrestrial and aquatic plants were different. The review paper improves the understanding of potential toxicity of MP themselves and the released and adsorbed chemicals to plants in the environment.