Physicochemical characteristics of ambient particles settling upon leaf surfaces of urban plants in Beijing

Particulate pollution is a serious health problem throughout the world, exacerbating a wide range of respiratory and vascular illnesses in urban areas. Urban plants play an important role in reducing particulate pollution. Physicochemical characteristics of ambient particles settling upon leaf surfaces of eleven roadside plants at four sites of Beijing were studies. Results showed that density of particles on the leaf surfaces greatly varied with plant species and traffic condition. Fraxinus chiuensis, Sophora japonica Ailanthus altissima, Syringa oblata and Prunus persica, had larger densities of particles among the tall species. Due to resuspension of road dust, the densities of particles of Euonymus japonicns and Parthenocissus quinquefolia with low sampling height were 2-35 times to other taller tree species. For test plant species, micro-roughness of leaf surfaces and density of particles showed a close correlation. In general, the larger micro-roughness of leaf surfaces is, the larger density of particles is. Particles settling upon leaf surfaces were dominantly PM30 （particulate matter less than 10 μm in aerodynamic diameter; 98.4%） and PM2.5 （particulate matter less than 2.5 μm in aerodynamic diameter; 64.2%） which were closely relative to human health. Constant elements of particles were C, O, K, Ca, Si, Al, Mg, Na, Fe, S, Cl and minerals with higher content were SiO2, CaCO3, CaMg（CO3）2, NaCI and 2CASO4. H2O, SiO2. CaCO3 and CaMg（CO3）2 mainly came from resuspension of road dust. 2CaSO4. H2O was produced by the reaction between CaCO3 derived from earth dust or industrial emission and SO2, H2SO4 or sulfate. NaCl was derived from sea salt.

Effects of Urbanization,Soil Property and Vegetation Configuration on Soil Infiltration of Urban Forest in Changchun,Northeast China

Urban forest soil infiltration, affected by various factors, is closely related with surface runoff. This paper studied the effect of urban forest types, vegetation configuration and soil properties on soil infiltration. In our study, 191 typical plots were sampled in Changchun City, China to investigate the soil infiltration characteristics of urban forest and its influencing factors. Our results showed that the steady infiltration rates of urban forest soil were highly variable. High variations in the final infiltration rates were observed for different vegetation patterns and compaction degrees. Trees with shrubs and grasses had the highest infiltration rate and trees with bare land had the lowest infiltration rate. In addition, our results showed that the soil infiltration rate decreased with an increase in the bulk density and with a reduction in the soil organic matter content and non-capillary porosity. The soil infiltration rate also had significantly positive relationships with the total porosity and saturated soil water content. Urban soil compaction contributed to low soil infiltration rates. To increase the infiltration rate and water storage volume of urban forest soil, proper techniques to minimize and mitigate soil compaction should be used. These findings can provide useful information for urban planners about how to maximize the water volume of urban forest soil and decrease urban instantaneous flooding.

A fine-scale assessment of the ecosystem service-disservice dichotomy in the context of urban ecosystems affected by alien plant invasions

Background: Natural resources within and around urban landscapes are under increasing pressure from ongoing urbanisation, and management efforts aimed at ensuring the sustainable provision of ecosystem services(ES) are an important response. Given the limited resources available for assessing urban ES in many cities, practical approaches for integrating ES in decision-making process are needed.Methods: We apply remote sensing techniques(integrating LiDAR data with high-resolution multispectral imagery)and combined these with supplementary spatial data to develop a replicable approach for assessing the role of urban vegetation(including invasive alien plants) in providing ES and ecosystem disservices(EDS). We identify areas denoting potential management trade-offs based on the spatial distribution of ES and EDS using a local-scale case study in the city of Cape Town, South Africa. Situated within a global biodiversity hotspot, Cape Town must contend with widespread invasions of alien plants(especially trees and shrubs) along with complex socio-political challenges. This represents a useful system to examine the challenges in managing ES and EDS in the context of urban plant invasions.Results: Areas of high ES provision(for example carbon sequestration, shade and visual amenity) are characterized by the presence of large trees. However, many of these areas also result in numerous EDS due to invasions of alien trees and shrubs – particularly along rivers, in wetlands and along the urban edge where tall alien trees have established and spread into the natural vegetation(for example increased water consumption, increased fire risk and reduced soil quality). This suggests significant trade-offs regarding the management of species and the ES and EDS they provide.Conclusions: The approach applied here can be used to provide recommendations and to guide city planners and managers to fine-tune management interventions at local scales to maximise the provision of ES.

Review of Researches on the Protection of Urban Plant Diversity

With the accelerating urbanization and population explosion, urban ecological environment has been seriously damaged, ecosystem has become unbalanced, and plant diversity has reduced constantly. This paper analyzed domestic and foreign literatures on the protection of urban plant diversity in recent years, summarized the previous researches on the protection of urban plant diversity, and major measures for protecting urban plant diversity.

花楸树——城市绿化的新贵

花楸树为蔷薇科苹果亚科花楸属植物,落叶乔木或灌木,高达8m。具有很高的园林观赏价值。花楸树引种驯化成功并应用于城市园林绿化,将为北方城市增添一道亮丽的风景线,对丰富城市绿化树种特别是首都北京的绿化建设具有重要意义。

Influence of night-time light pollution on the photosynthesis and physiological characteristics of the urban plants Euonymus japonicus and Rosa hybrida

Background Night-time light pollution(NLP),which breaks the natural cycle of day and night,has become a new threat to urban ecosystems.Plants are the main component of urban ecosystems and play an irreplaceable role in maintaining urban ecological balance.The effects of NLP with various radiation sources,including green,white,blue and red light provided by light-emitting diodes,on urban plants,Euonymus japonicus and Rosa hybrida,were examined in a block field experiment.Results NLP caused photoinhibition and oxidative stress in plants,and the extent of the deleterious effects varied with the spectral distribution of artificial light sources and species.Both E.japonicus and R.hybrida were more sensitive to blue and red light,which reduced the pigment concentration,net photosynthetic rate,stomatal limit value,effective quantum yield,apparent electron transfer rate and photochemical quenching coefficient,and markedly increased the malondialdehyde content and total antioxidant capacity.However,those negative effects under white light were only present in E.japonicus and not in R.hybrida.Furthermore,blue and red light significantly decreased the stomatal conductance of E.japonicus.In contrast,green light had no significant effect on the above indices for both species.All spectra did not significantly change the sugars and starch contents for either species.Conclusions Considering that the spectral distribution of artificial light at night in cities has great heterogeneity and that its effect varies with plant species,it is important to arrange tree species with NLP tolerance and install appropriate light sources in urban areas based on the corresponding physiological responses and adaptation of urban trees.

Feasibility of Wind Power Generation for the Reduction of Power Costs in Residential Buildings

The installation of wind power generators on buildings located in areas with regular winds may be a suitable investment in a renewable power source. Brazil has a high eolic potential, where the annual mean wind speed may reach over eight meters per second. This case study is aimed to assess the economic feasibility of the installation of small wind power plants in urban areas. This work evaluates a project for the installation of a vertical axis wind turbine in three buildings （15-, 22-, and 26-story） including the following stages： （1） installation of a real-time power meter in the 15-store unit; （2） demand analysis of the 26-store building＇s power consumption; （3） winds survey along the coast of the State of Ceara; （4） analysis of the wind turbines available in the market; （5） simulation aimed to choose the system. Vertical wind power generators offer better conditions of use in urban areas. The turnover time was established to be between four and six years in the three studied units. The installation of a wind power generator on buildings in regions with an adequate eolic regimen reaches a financial return of the investment before the end of the equipment＇s lifespan.

ROLE OF MEDICINAL AND AROMATIC PLANTS IN MODERN URBAN COMMUNITIES OF BRUSSELS

Medicinal and aromatic plants(MAPs)have been used by humans for centuries.A big part of the knowledge and interest in MAPs was lost during periods of intensive industrialisation and urbanisation.According to the estimations of the United Nations,the world urban population is expected to increase by 84%by 2050.

Tolerance of Chrysantemum maximum to heavy metals:The potential for its use in the revegetation of tailings heaps

To find if ornamental plants are applicable to the remediation of metal-polluted areas, the tolerance of chrysanthemum plants （Chysanthemum maximum） var. Shasta to different metals under hydroponic conditions was studied. Their responses as influenced by the mycorrhizal fungus Glomus mosseae （Nicol. ＆ Gerd.） Gerdemann ＆ Trappe BEG25 on substrates containing mine residues were also investigated. Our results showed that chrysanthemum is a metal-tolerant plant under hydroponic conditions, plants behaving as Pb-excluders, whereas Cd, Cu and Ni were accumulated in roots. Low accumulation in flowers was observed for Cd and Cu but it was concentration-dependent. Ni and Pb were not translocated to flowers. Shoot biomass was not significantly affected by the different rates of mine residue addition for both mycorrhizal and non-mycorrhizal plants. Mycorrhizal plants accumulated less Pb and Cu in both shoots and roots than non-mycorrhizal plants. Chysanthemum could be a prospective plant for revegetation of tailings and the use of inoculation may decrease plant metal accumulation in polluted soils.

A barrier to metal movement: Synchrotron study of iron plaque on roots of wetland plants

A wetland with attractive plants hosting birds and other wildlife is an esthetically pleasing prospect that is gaining popularity as a way of stabilizing or remediating metalcontaminated soils and sediment（Weber and Gagnon,2014;