Plastic pollution is a global concern due to its adverse effects on ecological systems. Plastic disposal and degradation release small fragments known as microplastics (MP) that can accumulate, infiltrate, and travel through soil, air, water, plants, and the environment. Studies indicate the omnipresence of MPs in soils and show their potential to influence seed germination, plant growth, and development. To investigate the effects of microplastics on seed germination, two replicated germination experiments were conducted under controlled conditions in germination chambers, SciBrite TM LED lighting at their optimum germination temperature of alternating 22/35°C day/night for a 14-hour photoperiod for 30 days at Florida Gulf Coast University. Seeds of Lettuce (Lactuca sativa), a widely cultivated horticultural crop were sown in petri plates (100 x 15 mm) containing four different soil amendments with microplastics PET (polyethylene terephthalate) fiber-filled microplastics (v/v) at 0.5%, 1%, 1.5%, and 2% concentrations and sizes < 125 µm, 126-250 µm, 251-375 µm, and 376-500 µm. Seeds were considered germinated with the protrusion of the radicle from the embryo. Germinated seeds were tossed away and calculated for Germination % (GP) and Mean Germination Time (MGT). Our preliminary results showed microplastics at lower concentrations of 0.5% and 1.0% decreased GP and increased MGT compared to higher concentrations of MPs. Small MP sizes showed negligible impact on the GP and MGTs. Future research will involve conducting pot experiments in a hoop house at the Southwest Florida Research and Extension Center (SWFREC), UF/IFAS, Immokalee to assess the impact of microplastics on plant growth, development, plant physiology and regulation. Data collection will include measurements of plant height, leaf chlorophyll content, photosynthetic gas exchange, leaf area Index (LAI), fresh and dry plant biomass (g), visual rating, and spectral signatures of healthy versus stressed plants at various intervals of crop growth stages. Keywords: PET microplastics, germination %, mean germination time, physiology, spectral signatures
