Effects Of Atmospheric Particulate Matter On Five Evergreen Coniferous Trees In Changchun

In this study,five species of coniferous trees in Changchun City were used as research objects.By measuring the amount of particulate matter retained per unit leaf area of tree leaves,to clarify the effects of different tree species on the retention capacity of atmospheric particulate matter,the effects of different heights of tree crowns and different ages of branch leaves on the retention capacity of atmospheric particulate matter,and the effects of different tree species on the retention capacity of atmospheric particulate matter in different gradients of urbanization.The relationship between leaf structural characteristics such as leaf area,leaf length,leaf width,leaf circumference and aspect ratio,and their ability to retain atmospheric particulate matter was investigated by using scanning electron microscopy to observe the leaf surface micromorphological characteristics such as stomata and sulci on the leaf surface of each tree species.The results of the study showed that:(1)The ability of different coniferous tree species to retain atmospheric particulate matter differs significantly,and the influence of leaf structural characteristics and leaf surface micromorphological characteristics on the retention capacity of different tree species varies depending on the species.The order of dust retention per unit leaf was as follows: Abies holophylla Maxim.> Picea koraiensis> Pinus sylvestris var.mongholica Litv.> Pinus koraiensis>Pinus tabuliformis var.mukdensis.Among them,Abies holophylla Maxim.exhibited a strong ability to retain atmospheric particulate matter.The ability of Pinus tabuliformis var.mukdensis to retain atmospheric particulate matter was significantly and positively correlated with the width of gullies on the upper surface of leaves and the diameter of stomata on the upper surface of leaves Picea koraiensis was significantly and positively correlated with the width of gullies on the upper surface of leaves,while Abies holophylla Maxim.was significantly and negatively correlated with the diameter of stomata on the upper surface of leaves,and Pinus koraiensis was significantly and positively correlated with the diameter of stomata on the lower surface of leaves.By scanning electron microscopy,the leaf surface of the tree leaf bumps,grooves,stomata,grooves and various leaf surface texture structure increases the roughness of the leaf surface,increasing the contact area of the tree leaf surface and atmospheric particles,to a certain extent to improve the ability of plants to retain atmospheric particles.(2)There were also significant differences in the retention capacity of perennial and annual branches at different heights of the canopy for atmospheric particulate matter.The retention capacity of perennial branches was higher than that of annual branches,and the retention capacity of middle canopy needles was better than that of lower canopy and upper canopy needles.The retention capacity of perennial needles of Picea koraiensis and Abies holophylla Maxim.and their leaf area were significantly and positively correlated,and the length of needles of perennial needles of Picea koraiensis,annual branches of Pinus sylvestris var.mongholica Litv.and annual branches of Pinus tabuliformis var.mukdensis were significantly and positively correlated.(3)The retention capacity of different tree species in different gradients of urban to rural was urban > suburban > rural.The particulate matter retention of Picea koraiensis was higher than that of Pinus sylvestris var.mongholica Litv.in the same gradient,and the location of the park and the surrounding environment maybe related to its retention capacity,while the retention capacity of Picea koraiensis spruce was significantly negatively correlated with its leaf area.The width of gullies on the leaf surface and the roughness of the leaf surface increased the retention capacity of the tree species.