Nano and submicron fluorescent polystyrene particles internalization and translocation in seedlings of Cichorium endivia L.

Contamination by plastics is one of the major causes of pollution of the terrestrial environment.Fragmentation of plastics into micro and nano particles may result in negative interactions betweenpolymers and terrestrial ecosystems. The effects of nano (20 nm) and submicron (200 nm) fluorescentpolystyrene (PS) particles, at different concentrations (0.01, 0.1, 1 g L-1), were analysed on chicoryplant (Cichorium endivia L.), considering the following endpoints: germination percentage andseedling development after 7 and 14 days exposure; genotoxic effects; polyphenols andphotosynthetic pigments content, antioxidant activity; absorption and translocation of PS particles inthe seedling tissues. The results indicated no negative effects on germination of both PS particles'sizes at any concentration; seedlings elongation was affected by 1 g L-1 of 20 nm PS after 7 daysexposure. Cytological analysis revealed no mitotic activity inhibition, but an uprising of chromosomalabnormalities in all treatments. Interestingly, photosynthetic pigments always increased after PSexposure. Seedlings treated with 20 nm PS showed intense fluorescence in the roots of 7 days and inthe shoots of 14 days, while 200 nm PS treated seedlings exhibited low fluorescence. Electronmicroscopy and infrared spectroscopy confirmed 20 nm PS internalization and transport inside theplant tissue and a reduced presence of 200 nm PS. These results suggest the importance not only ofparticle size in plastic internalization in plant tissues, but also of cytological damages induced byparticles too large to be bioaccumulated. From both aspects, consequences may arise for plant fitness,food safety and human health.