合肥市主要园林植物叶片滞尘能力的差异及形态特征解释

Differences among urban plants in accumulating particulate matter on leave surfaces in Hefei city and correlation to the morphological characteristics

颗粒物(particulate matter,PM)对人体健康具有潜在的危害,园林绿化植物可以充当空气过滤器,将这些颗粒物沉积在叶片上。研究不同绿化树种的颗粒物积累效应,有利于城市规划对树种的选择以改善空气质量。通过分级过滤法量化了合肥地区常见的24种绿化树种(10种灌木和14种树木)的植物叶片不同级别PM的积累,并将其与叶片形态特征联系起来。研究发现,观察到不同树种对颗粒物积累的差异,叶片表面沉积的大颗粒物(PM_(100))占总颗粒物重量的绝大部分,其次是粗颗粒物(PM_(10))和细颗粒物(PM_(2.5))。灌木树种花叶青木、石榴、椤木石楠和乔木树种无患子能有效地在叶片表面捕获不同大小的颗粒(PM_(2.5)、PM_(10)和PM_(100))。灌木树种的滞尘能力显著高于乔木树种。叶片PM积累量与比叶重、长宽比呈显著正相关。叶片绒毛是一个重要的结构,导致更多的叶片PM积累。利用这些树种间的滞尘差异,可以选择园林植物以捕捉大气颗粒物,并指导城市植物规划。由于乔木树种对PM_(2.5)和PM_(10)的滞留量较大,而灌木树种对PM_(100)的滞留量较大,因此,在城市绿化设计中应兼顾灌木和树种,合理搭配利用空间尺度以缓解城市大气污染。在合肥市以治理大气颗粒物污染为目标进行城市绿化时,可考虑选择花叶青木、石榴、椤木石楠和无患子等滞尘能力强的树种进行合理搭配。

Particulate matter(PM)is potentially harmful to human health,and urban plants serve as air filters to accumulate these particles.Studying the species effectiveness in accumulating PM may benefit urban planners in their attempts to improve air quality.Here,we quantified PM accumulation and linked to leaf morphological traits in 24 common native woody plants(10 shrubs and 14 trees)which are commonly cultivated along streets in Hefei area.It was found that large PM(PM_(100))deposited on leaf surfaces accounted for the majority of total PM by weight,followed by coarse PM(PM_(10))and fine PM(PM_(2.5)).Differences in the accumulation of PM were observed between the species.Shrub species,such as Aucuba japonica,Punica granatum,Photinia davidsoniae and tree species Sapindus saponaria,captured different particles sizes(fine,coarse and large)on their leaf surfaces efficiently.Shrub species tended to have significant higher capacity in particulate accumulation than tree species.Positive relationships existed between leaf PM retention amount and specific leaf weight and length/width ratio.Leaf hair seemed to be an important structure leading to more leaf PM accumulation.These differences among species can be used to select garden plants for trapping particulates and to guide urban plant planning.This multiple plant heights allows trees and shrubs to reduce PM on different spatial scales.Thus,considering the design of urban greening for the mitigation of urban atmospheric pollution,both shrub and tree species should be considered.Aucuba japonica,Punica granatum,Photinia davidsoniae and Sapindus saponaria,show high PM accumulation on the leaf surface significantly as common garden species in Hefei and often serve as landscape plants.These urban garden plants can be planted in areas with severe atmosphere pollution for their strong ability to absorb fine PM.