Abstract: [Objective] The objective is to provide reference for the greening tree species selection in Kunming city, based on the micro-morphological mechanism of leaf surface for leaf dust-retaining ability of the urban greening trees.[Method] Ten common greening tree species in Kunming were targeted. The leaves was washed with distilled water by using a numerical control supersonic cleaner (KQ5200), and then the eluent was filtered and dried. The dust detention of leaf surface was weighed using a 1/10 000 analytical balance. Leaf areas were measured by a LI-3000A leaf-measuring meter, and then the unit area dust detention and unifoliate dust detention were calculated. Four tissue blocks (5 mm×5 mm) per lamina (5 leaves per trees species) were cut, fixed with 2.5% glutaraldehyde solution, cleaned with 0.1 mol·L^-1 phosphate buffer solution, dehydrated with gradient-ethanol dehydration, fixed with n-butyl alcohol, and coated by E-1010 ion-plating. The micromorphological structure of these tissue blocks were then scanned by E-1010 scanning electron microscope, then the association of leaf surface structure with leaf dust detentions was analyzed for the ten greening tree species in Kunming. [Result] There were significant differences of unit area dust detention and unifoliate dust detention among different tree species (P<0.05). The unit area dust detention was ranked as Platanus orientalis > Magnolia grandiflora > Loropetalum chinense > Prunus cerasifera f. atropurpurea> Rhododendron simsii > Cerasus cerasoides > Celtis kunmingensis > Photinia glomerata > Cinnamomum camphora > Euonymus japonicus, while the order of unifoliate dust detention was Magnolia grandiflora > Platanus orientalis > Prunus cerasifera f. atropurpurea > Celtis kunmingensis > Photinia glomerata > Cerasus cerasoides > Loropetalum chinense > Rhododendron simsii > Cinnamomum camphora > Euonymus japonicus; Platanus orientalis, Loropetalum chinense and Prunus cerasifera f. atropurpurea with higher dust detention ability had high roughness and large amount of gullies with more ups and downs; There were threshold effects of leaf stomata density on dust detention capacity of these tree species; The area of guard cells was significantly positively correlated with unit area dust detention and unifoliate dust detention of leaf surfaces; The density of leaf cilium had positive correlations with unit area dust detention and unifoliate dust detention. [Conclusion] It is concluded that the micro-morphological structures of leaf surface (i.e., roughness, stomatal density, guard cell area, epidermal trichome density) are important factors affecting dust retention ability of the 10 greening tree species. The results can provide theoretical and data reference for the selection of greening tree species in Kunming.

Key words: micro-structure of leaf surface, unit area dust detention, unifoliate dust detention, green trees species, Kunming