Relationship between leaf micro-morphology and particulate matter wash-off characteristics of four tree species
[Objective] This study aimed to understand the restore characteristics of leaf surface in capturing particulate matter (PM) in rainfall process.[Method] This study selected foliage samples of 4 species with saturation PM capturing capacity to study its response to simulated precipitations (0,0.66,1.32,1.98,and 2.64 mm).Wash-off rates of PM2.0-8.0 (diameter of particulate matter 2.0-8.0 μm) and PM2.0 (diameter of particulate matter less than 2.0 μm) for leaves were calculated and the effects of leaf-surface micro-morphology structure on wash-off of PM2.0-8.0 and PM2.0 were also analyzed.[Result] The saturated amounts of particles captured by per unit leaf area of the four species were different with a decreasing order of Juglans regia ((37.05±2.54) μg/cm2 for PM2.0-8.0 and (5.30+0.74) μg/cm2 for PM2.0)＞Robinia pseudoacacia ((8.17 ± 1.15) μg/cm2 for PM2.0-8.0 and (2.47 ± 0.14) μg/cm2 for PM2.0) ＞ Populus cana densis＞Ginkgo biloba.With the precipitation of 2.64 mm,wash-off rates of PM2.0-8.0 (99.36％) and PM2.0 (99.44％) of G.biloba were high.Wash-off rate of PM2.0-8.0 (78.79％) was much higher than PM2.0 (52.02％) for R.pseudoacacia,while wash-off rate of PM2.0-8.0 (83.13％) was much lower than PM2.0 (95.84％) for J.regia.For P.canadensis,wash-off rates of PM2.0-8.0 (87.36％) and PM2.0 (80.29％) had no significant difference.The Scanning Electron Microscope (SEM) pictures showed that the surface of J.regia foliage had smooth wrinkles irregularly,stomas were small but large in number,and the wax layer was amorphous.R.pseudoacacia foliage surface was richly endowed with trichomes,epidermis cells had flat top covered with organized crystal wax layer,and stomas were in sparse levels.On the foliage surface of P.Canadensis,epidermis cells and wax were smooth,stomas were large in size but smaller in number compared with J.regia.For the G.biloba,epidermis cells were convex and densely covered by wax crystals,and stomas were thin and in large size.[Conclusion] Leaves with convex epidermal cells and without trichome (G.biloba & P.canadensis),covered by regular wax crystals (G.biloba) had low particle capturing capability and high PM wash-off rate.Conversely,the particle capturing capability of foliage (J.regia & R.pseudoacacia) was high,and the wash-off rate was low.
NETL
NSTL
万方数据
维普
