Effects of microplastics on lentil (Lens culinaris) seed germination and seedling growth.

Abstract

Widespread use of plastics and mishandling has resulted in severe environmental issues affecting seed germination and seedling growth. This study investigates the effect of polyethylene microplastics (740-4990nm PEMPs) on lentil (Lens culinaris) seed germination and seedling growth using Biospeckle Optical Coherence Tomography (bOCT), a technique that we successfully demonstrated earlier in visualizing the internal activity of plants. Lentil seeds were exposed to PEMPs bioassay for seven days with 10, 50, and 100mgL-1 concentrations. The average speckle contrast was calculated after 0h, 6h, 12h, and 24h of exposure, and statistically significant differences were observed just after 6h of exposure under all the treatments. However, with conventional parameters, germination viability, germination rate, root and shoot lengths, fresh and dry seedling weights, and antioxidative enzymes, no significant effect was observed until 2d of exposure. The results revealed that the presence of PEMPs significantly reduced the internal activity at the initial stages that could be visualized only by the use of bOCT, which has never been observed till now. Our results demonstrated for the first time the effect that microplastics indeed could hinder the internal activity during germination of the seeds, possibly resulting from the physical blockage of pores leading to stunted growth at later stages.