东北地区城市针叶树冬季滞尘效应研究

Dust absorption effect of urban conifers in Northeast China

对不同种针叶树同一降尘条件及同种针叶树不同降尘条件的滞尘能力进行研究 ,结果表明 ,针叶树在东北的冬季有很强的滞尘作用 ,不同的针叶树滞尘能力排序为沙松冷杉 >沙地云杉 >红皮云杉 >东北红豆杉 >白皮松 >华山松 >油松 .不同针叶树叶表面结构不同 ,滞尘量较小的白皮松、华山松和油松表面平滑 ,细胞与气孔排列整齐 ,而滞尘量较大的红皮云杉、沙松冷杉、东北红豆杉的针叶表皮平滑程度较差 ,细胞与气孔排列较前 3种植物差 ,在红皮云杉叶表面上有大小不等的瘤状物 .不同针叶树叶断面形状与滞尘量相关 ,白皮松和油松叶片的上表面呈弧形 ,不易附着灰尘 ;华山松叶片呈三棱形 ,上表面较窄 ,附着灰尘的量较小 ;两种云杉的叶片呈四棱形 ,上表面较 3种松属植物的叶片要宽与平展 ,因此相对滞尘量要大 ;沙松冷杉和东北红豆杉的叶断面形状都较扁、平 ,这种断面正是构成其滞尘量大于

Dust pollution is much heavier in winter than in other seasons in the cities of Northeast China, because the urban heating system consumes mainly coal as energy resources. Deciduous trees can hardly absorb dust because of their defoliation, and hence, urban conifer trees become more important in dust absorption in winter. This paper studied the dust absorption ability of 7 conifers under the same and different dust pollution status in Shenyang city, Northeast China. The results showed that the dust absorption ability of conifers was decreased in the order of Abies holophilla>Picea mongolica>P. koraiensis>Taxus cupidata>Pinus bungeana>P. armandi>P. tabulaeformis . Different conifers had different surface structures. Pinus bungeana, P. armandi and P.tabulaeformis had smooth surfaces, their cells and stomata arranged in order, and hence, their dust absorption ability was poor. P.koraiensis, Abies holophilla and Taxus cupidata had coarse surfaces,and their cells and stomata arranged out of order. There were even many tubercular things on the surface of P.koraiensis , and hence, their dust absorption ability was stronger.The dust absorption ability of conifers was related the shape of their leaf sections. The upper leaf surface of Pinus bungeana and P.tabulaeformis was arc, not opted to absorb the dust. The leaf section of P.armandi was prism, and its upper surface was narrow, and hence, its dust absorption ability was also poor. The leaves of Picea mongolica and P.koraiensis had four edges, their upper surfaces were broader and flatter than the former three species, and hence, they had stronger dust absorption ability. The leaf section's shape of Abies holophilla and Taxus cupidata was also broad and flat, which made the dust absorption ability of the two latter's was stronger than other three Pinus species and two Picea species.