Abstract: Dust-retention effect is an important ecological function of urban ornamental green land.Combining the investigation and GIS of the green land system in Wuhan Iron and Steel Company workshop area,this paper determined the dust-retention ability of different plant kinds and synusia types in this system,and quantitatively analyzed its dust-retention effect.The results showed that different ornamental plants had a greater difference in their dust-retention ability,which was mainly related to their leaf surface character,tree crown structure,and branch intensive degree.The dust-retention ability of different synusia types was in  order of deciduous broadleaved shrub>evergreen broad-leaved shrub>hedge>evergreen broad-leaved arbor>deciduous broadleaved arbor>conifer arbor>grass.The dust-retention amount of the ornamental green land in Wuhan lron and Steel Company workshop area was 9.51 t per day and 3 089.98 t per year,and the annual dust-retention amount of evergreen broad-leaved arbor was the highest,up to 991.68 t,while that of deciduous broad-leaved shrub was the minimum,only 0.0181 t.It could be concluded that the effective way to impove the dust-retention effect of ornamental green land was to choose the ornamental plants with strong dustretention ability,and to dispose the arbor,shrub and herb layer rationally to increase vegetation quantity.

Key words: Plant, Atmosphere, Exchange processes, Inverse methods