Response And Purification Effect Of Leaf Functional Traits Of 20 Garden Plants To Different Air Pollutants In Lanzhou City

Air pollution has become an important factor affecting the living environment and health and well-being of modern cities.Because of its functions in maintaining carbon and oxygen balance of urban ecosystem,absorbing heat and dust,reducing bacteria and noise,conserving water resources,maintaining biodiversity and beautifying the environment,garden plants have become the key indicators of ecological livable city construction.In the construction of urban ecological environment engineering,it is of great theoretical and practical significance to select and allocate garden plant species in order to improve the quality of urban ecological environment and realize the sustainable development of the city.In this study,20 kinds of common greening tree species in Lanzhou city are taken as the research objects.According to the air pollution situation in the research area,three pollution areas are divided,namely,Anning District is a clean control area,Qilihe district is a mixed commercial and residential area,Xigu District is an industrial area.20 species of woody plants,such as Sabina chinensis,Juniperus chinensis,Platycladus orientalis and Picea asperata,were selected as the experimental materials.15 leaf functional traits,such as leaf width(LL),leaf length(LL),leaf perimeter(LP),were selected for the experimental measurement,and the monitoring data of air pollutants were obtained at the same time.Through the study of the distribution characteristics,difference convergence and response to different atmospheric environment of plant leaf functional traits,it provides scientific basis for the refinement,digital selection and configuration based on the ecological benefits of garden plants in Lanzhou urban green space system.The results show that:(1)The variation degree and correlation of leaf functional traits.The variation range and variability of leaf functional traits of 20 garden plants are large,and the coefficient of variation is between 15.69% and 139.18%.LCC,LNC,LPC and SP are low variation characters,LDMC,SS and SOD are medium variation characters,while LW,LL,LP,LA,SLA,SLW,MDA and Pro are high variation characters.This study shows that there is a correlation between leaf morphological traits and leaf economic traits,but there is no correlation between them and LCC,LNC,LPC of plants,while LNC and LPC show a very significant positive correlation.(2)The difference of leaf functional traits and the analysis of leaf economic spectrum of different life forms.There are significant differences in leaf morphological characters among different life forms of plants,which are deciduous trees,deciduous shrubs and evergreen trees.In addition,LW,LL,LP,LA,SLA,SLW and LDMC of three kinds of living plants were significantly different in different pollution areas.The study also showed that in the same polluted area,there were significant differences in leaf characters among different living plants.In this study,the physiological characteristics of plants in different pollution areas were different,among which SOD,MDA and SP were significantly different in three pollution areas.There are differences among the physiological characters of different life forms,but none of them reach the significant level.The results of leaf economic spectrum analysis show that evergreen trees belong to the type of "fast investment income",while deciduous trees and shrubs tend to be on the resource axis of "slow investment income".(3)The absorption and purification efficiency and adaptability of garden plants.In addition,in the same pollution area,the difference of N content in leaves of different living plants is large;in different pollution areas,the difference of N content in leaves of the same living plants is large.This study shows that there are 12 kinds of plants with strong purification ability,i.e.Rosa chinensis,Prunus×cistena,Cedrus deodara,Platycladus orientalis,Hibiscus syriacus,Platanus orientalis,Sophora japonica,Amygdalus persica,Sabina chinensis,Buxus sinica,Syringa oblata and Juniperus chinensis;there are 3 kinds of plants with medium purification ability,i.e.Ligustrum×vicaryi,Prunus cerasifera and Picea asperata;while Rosa rugosa,Euonymus japonicus,Salix matsudana,Cornus alba and Berberis thunbergii have weak purification ability.In this study,leaf economic traits(SLA,SLW,LDMC)and physiological traits(SS,MDA,SP,Pro,SOD)were selected to evaluate the adaptability of plants.The results showed that the adaptability of 20 plants was Rosa rugosa,Amygdalus persica,Juniperus chinensis,Cornus alba,Platycladus orientalis,Picea asperata,Sabina chinensis,Prunus×cistena,Salix matsudana,Rosa chinensis,Prunus cerasifera,Syringa oblate,Ligustrum×vicaryi,Hibiscus syriacus,Platanus orientalis,Sophora japonica,Cedrus deodara,Buxus sinica,Euonymus japonicus,Berberis thunbergii.