The Dispersions Of Airborne Pollen And Its Relationship With Major Climatic Parameters In Shijiazhuang

The research of airborne pollen is one of important contents of modern pollen process,and one of the important components in building of the quantitative relationship amongpollen-vegetation-climate, and is the foundation in construction of pollen dispersal patternanalysis model. In this paper, through the airborne pollen analysis of130samples collectedfrom2007to2010in Shijiazhuang city, combined with the meteorological data, thedispersion rules and characteristics of airborne pollen are revealed in Shijiazhuang, and theimpact of climate factors are discussed to pollen percentages and influxes for different taxa indifferent seasons. The results can provide important modern process basis for correctinterpretation of fossil pollen spectra and the reconstruction of paleovegetation andpaleoclimate. The research can also provide important reference for the prevention of pollenallergy in Shijiazhuang city.Refer to the vegetation distribution in the studied area, the airborne pollen taxa can bedivided into the local pollen grains and the regional pollen grains. In pollen assemblages, Thepercentages of Local pollen taxa (e.g. Juglans, Populus, Pinus, Platanus, Rosaceae, Artemisia,Chenopodiaceae, Poaceae) account for more than80%of the total pollen amount; on the otherhand, the percentage of regional pollen taxa (e.g. Betula, Quercus, Ostryopsis, Elaeagnus,Urtica+Humulus, Cereals) only account for less than20%of the total pollen amount,indicating that airborne pollen grains comes mainly from local vegetation, while can beinfluenced by regional vegetation in Shijiazhuang.The contrast of airborne pollen assemblages in Shijiazhuang from2007to2010indicatesthat general characteristics of airborne pollen assemblages are as following: Firstly, theaverage arboreal pollen percentages are34.6%,30.0%,33.6%, the average pollen influxes are197、231、186grain·cm-2·15d-1, with Juglans, Populus, Pinus and Platanus as the dominantpollen taxa; the average shurb pollen percentages are3.2%,7.3%,2.9%, the average polleninfluxes are13,59,9grain·cm-2·15d-1, with Rosaceae, Ostryopsis and Elaeagnus as commonpollen taxa; the average herbaceous pollen percentages are58.2%,60.7%,61.5%, the averagepollen influxes are147、120、161grain·cm-2·15d-1, with Artemisia, Chenopodiaceae,Urtica+Humulus, Cereals and Poaceae as the major pollen taxa; Content of fern spores islower. Secondly, the main pollen types show obvious differences in different seasons. For examples, Populus and Ulmus are the dominant pollen taxa in early spring; Juglans andPlatanus are the dominant pollen taxa in mid-spring; Pinus, Quercus and Betula are thedominant pollen taxa in late spring; Poaceae, Cereals and Fabaceae are the dominantherbaceous pollen types in late spring and early summer; Artemisia, Chenopodiaceae andUrtica+Humulus are the dominant pollen taxa from late summer and early autumn to the endof winter. It shows that airborne pollen assemblages can indicate the seasonal variation ofplant florescence.The impact of climatic parameters on pollen percentages and influxes show somedifferences. The CCA analysis betwwen pollen percentages and climatic parameters suggestthat the percentages of most pollen taxa are obviously influenced by wind speed and vaporpressure. Wind speeds usually have significant positive correlations with the percentages ofPinus, Quercus, Betula and Juglans, and significant negative correlations with the percentagesof Artemisia, Chenopodiaceae and Urtica+Humulus. Vapor pressures often have significantpositive correlations with the percentages of Chenopodiaceae, Urtica+Humulus and Fabaceae.Correlation analyses between major pollen taxa influxes and climatic parameters from2007to2010indicate that pollen influxes of majority arboreal pollen taxa show significant positivecorrelations with wind speed and significant negative correlations with relative humidity; andmajority herbaceous pollen taxa show significant positive correlations with the airtemperature and vapor pressure.Correlation analyses between major pollen taxa influxes and climatic parameters indifferent seasons indicate that pollen influxes are mainly influenced by air temperature andvapor pressure in spring: the pollen influxes of Populus and Ulmus show significant negativecorrelations with both the air temperature and vapor pressure; while Juglans, Platanus,Rosaceae and Elaeagnus show significant positive correlations with the air temperature andvapor pressure of February to April; Pinus, Quercus and Betula show significant positivecorrelations with both the air temperature and vapor pressure. Pollen influxes of majorityarboreal pollen show significant negative correlations with relative humidity and vaporpressure in summer. Pollen influxes of majority arboreal pollen show significant positivecorrelations with wind speed, and majority herbaceous pollen show significant positivecorrelations with the air temperature and vapor pressure in autumn. No significant correlationcan be found between pollen percentage and any climatic parameters in winter.Comparison of the airborne pollen assemblages in this study and that in20years ago inShijiazhuang indicates that the dominant pollen taxa have some differences. In this study, according to the dispersal characteristics of different pollen types, Platanus, Artemisia,Urtica+Humulus and Chenopodiaceae are the possible major allergic pollen types. ThePlatanus have the highest pollen influxes on April and May, and Artemisia, Urtica+Humulusand Chenopodiaceae on July to September. If you are allergic to these pollen types, pleasetake care in the periods of their higher influx values.