Soil moisture and texture mediating the micro(nano)plastics absorption and growth of lettuce in natural soil conditions

Abstract

The absorption of microplastics and nanoplastics (M(N)Ps) by plants has been reported, but their uptake from natural soils that is similar to the agro-ecosystems remains unclear. Additionally, the influence of soil environment factors, such as soil moisture (SM) and soil texture (ST), on the absorption and migration of M(N)Ps from soil remains uncertain. We examined absorption of M(N)Ps of various sizes by lettuce (Lactuca sativa) in Mollisols with varying levels of SM (5, 10, 15 ml water per 2d) across different ST (23.67% and 44.09% sand) under controlled incubation conditions. Our results revealed high M(N)Ps absorption by lettuce from natural soil, with notable distribution, particularly in stem and even on leaf surfaces, suggesting to the potential migration path. M(N)Ps presence reduced lettuce growth across different SM and ST compared with the control group (without M(N)Ps), possibly due to the uptake of M(N)Ps. Higher SM promoted plant growth and transpiration, enhanced M(N)Ps absorption and migration, and resulted in higher concentration observed in the leaves. Moreover, an interaction between SM and ST was observed, affecting the distribution of M(N)Ps in lettuce organs. These findings underscore the significance of SM and ST as key factors affecting M(N)Ps absorption and distribution in plants.