Impact of microplastics on plant biogenic volatile organic compounds emission: A preliminary study

Plants produce biogenic volatile organic compounds (BVOCs) that are essential for interacting with the environment. As emerging pollutants, microplastics (MPs) may influence BVOCs emissions, yet their effects remain poorly underexplored. This study employed headspace solid phase microextraction coupled with gas chromatography - mass spectrum to investigate the impact of MPs on the BVOC emission profiles of lettuce (Lactuca sativa). Our results demonstrated that polystyrene (PS) MPs exposure, even at environmental concentrations (0.5-2 mg/L), significantly altered BVOC profiles, with a marked increase in aldehydes and ketones. A 7-fold increase in phenylacetaldehyde and benzaldehyde at 50 mg/L indicated stress-related metabolic changes, which also evidenced by reduced superoxide dismutase (SOD) activity and shifts in root microbial communities. The key discriminating BVOCs identified suggest that the presence of MPs impact plant survival and adaptability, with emissions originating from various metabolic pathways, including phenylpropanoid, lipoxygenase, and terpenoid synthesis pathways. Furthermore, variations in type, size, and aging treatment of MPs influenced BVOCs emission patterns. Our findings underscore the significance of BVOCs as indicators of exposure risks associated with MPs and highlight the ecological threats posed by these pollutants.