[Leaf micro-morphology and features in adsorbing air suspended particulate matter and accumulating heavy metals in seven trees species].

ABSTRACT

The purpose of this study was to assess the relationship between tree leaf micro-morphology and features in adsorbing air suspended particulate matter and accumulating heavy metals. Seven tree species, including Ginkgo biloba, at heavy traffic density site in Huainan were selected to analyze the frequency of air particulate matter retained by leaves, the particle amount of different sizes per unit leaf area retained by leaves and its related micro-morphology structure, and the relationship between particle amount of different sizes per unit leaf area retained by leaves and its related accumulation of heavy metals. We found that the species characterized by small leaf area, special epidemis with abundant fax, and highly uneven cell wall, as well as big and dense stomata and without trichomes mainly absorbed fine particulate matter; while those species with many trichomes mainly retained coarse particulate matter. Accumulation of heavy metals in leaves of the seven species was significantly different except for Ph. Tree species with high capacities in heavy metal accumulation were Ginkgo biloba, Ligustrum lucidum, and Cinnamomum camphora. Accumulation of Cd, Cr, Ni, Zn, Cu and total heavy metal concentration for seven tree species was positively related to the amount of particulate matter absorbed. Correlation coefficients of d10 vs d2.5, d10 vs d1.0, d2.5 vs d1.0 were 0.987, 0.971, 0.996, respective, and the correlate level was significant. The ratios of d2.5/d10, d1.0/d10, d1.0/d2.5 were 0.844, 0.763, 0.822, indicating that the particulate matter from traffic was mainly fine particulates.