Plants interact with microplastics in their environment, but the primary way these larger plastic fragments interact, based on available research, is through adsorption onto the plant surface.
Understanding Plant Interaction with Plastics
While the absorption of environmental contaminants into plant tissues is a complex process, the mechanism by which plastic particles interact depends heavily on their size. The reference provided highlights a key distinction between how nanoplastics and microplastics interact with plants.
Microplastics vs. Nanoplastics Entry
- Nanoplastics (typically <1 µm) are small enough that they can enter plant tissues. According to research, nanoplastics may find pathways into the plant through existing cracks on the surface or via microscopic pores called stomata (Mateos-Cárdenas et al., 2021).
- Microplastics (typically >1 µm, up to 5 mm) are considerably larger than nanoplastics. Due to their size, they are less likely to pass through the small openings or pores used by nanoplastics. Instead, microplastics tend to aggregate and become adsorbed onto the plant surface (Mateos-Cárdenas et al., 2021).
Therefore, while nanoplastics may be absorbed into the plant structure, microplastics, being larger, are more likely to remain attached to the external surface of the plant.
How Microplastics Adhere to Plant Surfaces
The process of adsorption involves particles sticking to a surface. For microplastics on plants, this can occur through various interactions between the plastic particles and the plant's outer layer (cuticle, cell walls). These interactions can be influenced by factors like:
- The surface properties of the microplastic (shape, charge, roughness).
- The surface properties of the plant (waxes, charge distribution, presence of hairs or trichomes).
- Environmental conditions (e.g., presence of water, soil composition).
Once adsorbed onto the surface, microplastics can potentially impact the plant's ability to exchange gases or absorb light, although the full ecological implications are still under extensive study.
Key Takeaway
Based on the provided reference, the mechanism described for the interaction of microplastics with plants is primarily adsorption onto the plant surface, contrasting with the potential entry of smaller nanoplastics into the plant's internal tissues.
Reference:
Mateos-Cárdenas, A., et al. (2021). [Information from 09-Aug-2023] Nanoplastics can enter plants through cracks or via the stomata, whereas due to their larger size, it is more likely that microplastics aggregate and are adsorbed onto the plant surface.
