Dynamic fluctuations in plant leaf interception of airborne microplastics

Area of Science:

• Environmental Science
• Plant Biology
• Ecotoxicology

Background:

• Plant leaves act as sinks for airborne microplastics (MPs).
• Traditional models for particulate matter adsorption are insufficient for leaf-MP interactions due to MPs' unique properties.
• Understanding MP interception by leaves is crucial for assessing terrestrial plant exposure to airborne pollution.

Purpose of the Study:

• To investigate the diurnal fluctuations and interspecies differences in microplastic interception by plant leaves.
• To explore the role of leaf micromorphological structures in microplastic interception.
• To challenge the static equilibrium model for microplastic accumulation on leaves.

Main Methods:

• A 7-day field study was conducted in Nanning to quantify leaf-intercepted MPs.
• Microplastic abundances and characteristics were analyzed across different plant species (conifers, arbors, shrubs).
• Partial least-squares path modeling was used to identify factors influencing MP interception.

Main Results:

• Leaf-intercepted MP abundances exhibited dramatic diurnal fluctuations (CV=0.459) and significant interspecies differences (CV=0.353).
• Conifers intercepted more MPs than arbors, which intercepted more than shrubs.
• Stomatal variation and divergence were identified as primary drivers of diurnal and interspecies variations, respectively.

Conclusions:

• Microplastic interception by leaves is a dynamic process, not a static equilibrium.
• Leaf micromorphological structures, particularly stomata, significantly regulate the interception of airborne microplastics.
• This study enhances the understanding of plant-environment interactions concerning airborne pollutants.