Abstract:

Garden plants have the function of entrainment of atmospheric particulates and heavy metals,which can significantly improve the urban environment.The dust retentions on the leaf surfaces of Ligustrum lucidum,Platanus orientalis and Populus tomentosa were larger than that of Salix matsudana and Koelreuteria paniculata,and the dust retention amount per leaf surface of Ligustrum lucidum was the largest at an average level of 4.494 9±0.727 4g/m²,which was about 2.8 times as that of the smallest Salix matsudana .The dust retention of the 8 studied tree species reached the maximum during day 21 to day 27.The highest saturated dust retention was Ligustrum lucidum on the 24th day after raining with an amount of 7.201 8±0.026 4g/m² while the lowest,Salix matsudana,of 2.805 3±0.049 3g/m ² on day 21.The former was about 2.5 times as much as that of the latter.There was a positive correlation between the heavy metal content in leaves and the leaf dust retention,as well as between the heavy metal content in leaves and in the retentive dust,heavy metal content in the retention dust and the retention dust amount.The correlation of Cd,Pb content in leaves and dust retention reached a very significant level.The correlation coefficient between Cu,Ni,Pb and Zn content in leaves and in the retention dust reached more than 0.8,reaching a very significant level.The correlation coefficient between heavy metal content in the retentive dust and leaf dust retention is above 0.4,especially the highest correlation between Pb and dust retention with a coefficient 0.880.

Key words: trees, maximum dust retention, heavy metal content, leaf, heavy metal content in retention dust correlation