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Université du Hebei (2017)

Identification and Element Composition of Ubiquitous Lichens in A Desertified Grassland of Xilinhot,Inner Mongolia,North China


Titre : Identification and Element Composition of Ubiquitous Lichens in A Desertified Grassland of Xilinhot,Inner Mongolia,North China

Auteur : 刘四娃;

Grade : Master’s Theses 2017

Université : Université du Hebei

The lichens are symbiotic organisms with long lifecycle,slow growth and widely geographical distribution.They have been known as one of the most efficient organism widely used in biomonitoring atmospheric elemental deposition,adsorbing and accumulating elements much higher than their physiological requirements.However,study on their performance in this regard in desertified grassland areas with high dust input is still lacking.Lichen were collected and investigated in 16 sample sites sizing 400 km2 within a desertified grassland of Inner Mongolia,North China.The taxonomical study on 142 specimens show that 46 species belonging to 11 genera and 21 families were identified,among which 24 species belonging to 9 genera of Physciaceae and Parmeliaceae were dominant in the study area.Ecological study show : 1)a substrate diversity of lichens,with 16 corticolous lichens,14 saxicolous species,13 terricolous species,11 species on soil covered rocks,and 2 species on moss covered soil ;2)the lichen is dominated by foliose lichens(38species)and crustose lichens(8 species) ;and 3)19 speceis belonging to 11 genera were ubiquitous lichens occupying at least 3 sampling sites in the study,they are Xanthoparmelia camtschadalis(XPC),Rhizoplaca chrysoleuca(RZC),Ramalina sinesis(RS),Xanthoria elegans(XE),Phaeophyscia denigrata PHD),Physcia aipolia(PA),Cladonia humilis(CH),Melanelia tominii(MT),Melanohalea olivacea(MO),Peltula euploca(PET),Phaeophyscia hirtella(PHHe),Phaeophyscia hirtuosa(PHHu),Physcia tribacia(PT),Physconia detersa(PCD),Physconia grumosa(PCG),Rhizoplaca melanophthalma(RZM),Xanthoparmelia tinctina(XPT),Xanthoria fallax(XF),Xanthoria mandschurica(XM).The 19 ubiquitous lichens were included in the analysis of elemental composition analyses.Thirty elements(Al,Ba,Ca,Cd,Ce,Cr,Cs,Cu,Fe,K,La,Mg,Mn,Mo,Na,Ni,P,Pb,Rb,S,Sb,Sc,Sm,Sr,Tb,Th,Ti,Tl,V and Zn)in surface soil and 19 ubiquitous lichens were determined by inductively coupled plasma mass spectrometry(ICP-MS).The sources of element content and influencing factors on accumulation capability of lichens were analysed by multivariate statistical,enrichment factor(EF)and soil particle contamination degree(Fe/Ti).The data were also compared to relevant studies.The results show that : 1)lichen elemental composition can be used to characterize the elemental input of environments.In the study sites,as expected,dust input is a main source ofelements composition in lichens,and road traffic,a main anthropogenic sources human activity pollution,is a secondary source ;2)Similarities and dissimilarities were found between lichen species in accumulating capability of elements,and are highly influenced by the ecological and morphological characteristics of lichens.According to levels of terrigenous element and Ca,four groups were recognized : high terrigenous and Ca group(CH,XPT,PCD and MO),low terrigenous and Ca group(PA,XF,PHD and PHHe),high terrigenous with low Ca group(PHHu,PT,XE,PET and XM),and low terrigenous with high Ca(RZM,RZC,MT,RS,PCG and XPC) ;and 3)Seven lichens(XPT,RZC,RZM,PET,MT,XPC and RS)can be used as biomonitors for anthropogenic elements,in which Ramalina sinesis(RS),Rhizoplaca chrysoleuca(RZC)and Xanthoparmelia camtschadalis(XPC)were the best choices.In conclusion,lichens were abundant in the area and their elemental composition has been highly influenced by the desertified environments.Ramalina sinesis,Rhizoplaca chrysoleuca and Xanthoparmelia camtschadalis are the best species to monitoring the deposition of air pollutants in this area.

Mots clés : Arid and semi-arid; Atmospheric deposition; Sand dust input; Lichen biomonitoring;

Présentation (CNKI)

Page publiée le 31 janvier 2018