Dynamic Characteristics And Effects Of Volatile Organic Compounds Released By Landscape Plants

In this study,six common landscape plants in Beijing are taken as the research objects,and the dynamic headspace bag collection and TCT-GC-MS are used to analyze and identify the composition and relative content of volatile organic compounds in plants,and the variation characteristics of monthly and daily dynamics.At the same time,the beneficial BVOCs for human body are screened by consulting literature and data.The relative content and species number of beneficial BVOCs in Platycladus orientalis,Cedrus deodara,Taxus cuspidata,Ginkgo biloba,Syringa beijingensis and Rosa chinensis are compared and analyzed.At the same time,FAC coefficient method is introduced to calculate the potential of volatile organic compounds from six landscape plants to generate secondary organic aerosols(SOA).In this study,the main landscape plants in Beijing are scientifically evaluated from the two perspectives of the positive impact of plant volatile organic compounds on human health and the negative impact on atmospheric environment,which provid a theoretical basis for the reasonable selection and scientific allocation of landscape tree species in Beijing.The main research results are as follow :(1)Six landscape plants are identified as 9 compounds including alkenes,alkanes,aromatic hydrocarbons,alcohols,aldehydes,ketones,esters,organic acids,ethers and others.There are 133 species released by Platycladus orientalis,114 species released by Cedrus deodara and 134 species released by Taxus cuspidata.The contents of BVOCs released by three coniferous plants are significantly different among categories.Ginkgo biloba release105 species,Syringa pekinensis release 111 species,Rosa chinensis release 118 components.The content distribution of BVOCs released by the three broad-leaved plants is relatively uniform.(2)In the monthly dynamic variation characteristics of plant volatile organic compounds,the relative content of major categories of olefins in Platycladus orientalis and Cedrus deodara show a continuous upward trend,showing November > October > September >August > July.The main categories of alcohol compounds in Taxus cuspidata shows a gradually decreasing trend.The changes of alkane in Ginkgo biloba shows a trend of ’ two peaks and two valleys ’.The relative content of alkane in August is higher than that in the other three months.The relative content of aldehydes in July and August is higher than that in September and October.Olefins in Syringa pekinensis shows a trend of gradual increase,while alcohols decreases in turn every month.The change of esters in Rosa chinensis is ’ two peaks and two valleys ’,the relative content of esters in July and October is higher than that in the other three months.The change of alcohols is similar to that of esters,but it is higher in July and September than that in other months.(3)In the diurnal variation characteristics of volatile organic compounds in plants,the relative content of olefins in Platycladus orientalis and Cedrus deodara show a ’ two peaks and three valleys ’ type change,and the relative content in the afternoon is higher than that in the morning.Alcohols in Taxus cuspidata shows a ’ single peak ’ change,and the relative content in the morning is higher than that in the afternoon.Alkanes in Ginkgo biloba shows ’single valley ’ type change,the relative content is the lowest at 13:00,higher in the morning than in the afternoon,aldehydes shows ’ two peaks and two valleys ’ type change,the relative content in the afternoon is higher than in the morning.The relative content of alkenes in Syringa pekinensis shows a ’two peaks and two valleys ’ type change,which is higher than that in other periods in the morning and evening.On the contrary,the relative content of alcohols is lower than that in other periods in the morning and evening,the overall change is a’ single peak ’ type change.The esters in Rosa chinensis shows a ’ single peak’ change,with the highest relative content at 13:00-14:00,olefin compounds has no obvious change trend.(4)The typical growing season months(July)are selected for comparative analysis,and the components and relative contents of beneficial BVOCs released by coniferous and broad leaved plants show interspecific specificity.The beneficial BVOCs released by six landscape plants include six categories of olefins,alcohols,aldehydes,ketones,esters and others.The relative contents of beneficial BVOCs in the total BVOCs of each plant rank as Cedrus deodara(86.88 %)> Platycladus orientalis(82.03%)> Rosa chinensis(74.11%)> Syringa pekinensis(58.44%)> Ginkgo biloba(50.64%)> Taxus cuspidata(30.51%).Platycladus orientalis and Cedrus deodara in coniferous plants mainly release beneficial olefin compounds with relative contents of 77.59% and 71.61%,respectively.The proportion of beneficial aldehydes is the highest(12.92%),followed by beneficial olefins(7.77%);the common components of three coniferous plants are(+)-α-pinene,(+)-limonene,β-caryophyllene,and β-caryop-hyllene.Broad leaved plants are rich in beneficial alcohols,aldehydes and esters:Ginkgo biloba(34.91%),Syringa pekinensis(41.83%),Rosa chinensis(55.98%);the common components of three broad-leaved plants are(+)-α-pinene,(+)-limonene,basilene and cis-3-hexene-1-ol.(5)Among six landscape plants,the maximum concentrations of secondary organic aerosols produced by volatile organic compounds of Platycladus orientalis,Cedrus deodara,Ginkgo biloba and Syringa pekinensis appear in July,and gradually decrease.The maximum concentrations of secondary organic aerosols produced by volatile organic compounds in Taxus cuspidata and Rosa chinensis appear in August and October,respectively,with ’ single peak ’ and ’ two peaks and two valleys ’ changes.The daily variations show a ’ single peak ’pattern of firstly increasing then decreasing.Except that the maximum SOA concentration of Taxus cuspidata appears at 16:00-17:00,and the SOA concentration of volatile organic compounds from five landscape plants reach the peak at 13:00-14:00.Comprehensively considering the health care effect of plants on releasing beneficial volatile organic compounds and the related characteristics of the potential for generating secondary organic aerosols,green space and forest parks other than landscaping roads are suitable for planting Platycladus orientalis and Cedrus deodara with high olefin volatile emission.Taxus cuspidata has a broad-spectrum attraction to mosquitoes and other blood-sucking insects due to its main volatile component 1-octene-3-ol.It is not suitable for large-scale planting as ornamental plants that can directly contact tourists.The relative contents of beneficial aldehydes,esters and alcohols released by broad leaved plants such as Ginkgo biloba,Syringa pekinensis and Rosa chinensis are relatively high.The aromatic characteristics can be used to create rehabilitation landscapes,such as health botanical gardens,and regulate human physical and mental health.