# Polyester microfibers delay growth of cherry tomato (Solanum lycopersicum var. cerasiforme) throughout the lifecycle

## TL;DR

Polyester microfibers negatively affect cherry tomato growth from seed to maturity, mainly through physical effects.

## Contribution

This study is the first to assess the lifecycle impact of polyester microfibers on cherry tomato development in peaty soil.

## Key findings

- Polyester microfibers reduced emergence success by 11% and delayed flowering and ripening.
- Microfibers decreased soil water holding capacity and reduced adult plant biomass.
- Chemical additives from microfibers did not affect plant development.

## Abstract

Agroecosystems are increasingly recognized as major basins for terrestrial microplastics. Many agricultural practices have led to high loading of plastic mulch films, synthetic microfibers, and other microplastics onto fields. There is demonstrated ability for microplastics to influence soil properties and plant productivity, but these effects are highly variable by species, soil, and life stage. Here, we conduct a lifecycle assessment of how polyester microfibers, a dominant biosolid contaminant, affect the development of cherry tomato (Solanum lycopersicum var. cerasiforme) in peaty growing medium. We distinguish the importance of physical and chemical characteristics of microfibers by comparing plants in soil containing microfibers at 0.5% soil weight, or soil watered with leachate isolated from microfibers. We find that polyester microfibers reduce emergence success by 11%, delay flowering and ripening time by several days, and lead to a reduction in biomass in adult plants. However, we observe no effect of chemical additives from microfibers on plant development. We also note a decrease in soil water holding capacity from microfibers. Overall, we conclude that physical microfiber properties or physical/chemical interactions are the likely drivers of biological effects. These findings emphasize that microfibers have impacts beyond mineral soils, and consequences at every stage of plant development.