Study On The Vegetation And Plant Functional Traits Of Ammopiptanthus Mongolicus

Ammopiptanthus is the relic plant surviving in the process of the ancient Mediterranean retreat,climate drought,mainly distributed in regions of Inner Mongolia,Gansu,Ningxia and Xinjiang.Ammopiptanthus mongolicus is the only evergreen broad-leaved shrubs in arid regions of northwest China,which is listed as a national third-class protected plants.The study of A.mongolicus has important academic value,ecological value,and economic value.The research on vegetation and eco-physiological characteristics of A.mongolicus was carried out in Alashan and Mengxi region of Inner Mongolia,Zhongwei region of Ningxia,Jingtai region of Gusan in May and July.According to the different soil matrix,two plots were selected for each region:sandy plots and gravel-like plots.The photosynthetic characteristics of the leave of A.mongolicus were measured by Li-6400 portable photosynthetic apparatus,including the diurnal variation of gas exchange,the photosynthetic response to light and CO2.The samples of leaves and seeds of A.mongolicus were collected and used for the morphological measurement and the germination experiment.The main results and conclusion were as follows:(1)The vegetation characteristics of Ammopiptanthus mongolicusThe vegetation of A.mongolicus was composed of shrubs and herbs,including 41 species belonging to 12 families and 39 genera.There were significant differences in the composition of A.mongolicus communities in different distribution areas.The composition of A.mongolicus communities was affected by seasonal changes.The constructive species of herbaceous plants in most plots were different between May and July,except the gravel-like plot of Jingtai region and the sandy plot of Alashan region.The biodiversity of A.mongolicus communities were changed in different distribution areas and habitats.The diversity of shrub species was highest in the gravel-like plot of Zhongwei region,and lowest in the gravel-like plot of Zhongwei region.The diversity of herbaceous plants in most plots was greatly affected by season changes,which was higher in July than that in May.The age structure of A.mongolicus population was divided into 12 levels(???).The results of statistical analysis showed the individual numbers of young and middle age were fewer in A.mongolicus populations,mainly concentrated in the age of ?.It indicated that A.mongolicus populations was facing serious aging and the regeneration ability of population was relatively weak.The distribution pattern of A.mongolicus population was uniform distribution in most regions,except aggregative distribution in gravel plots of Alashan region.In the uniform distribution of samples,the average degree of A.mongolicus population was different,which the average degree was highest in the gravel plot of Mengxi region,lowest in the sandy plot of Alashan region.(2)Leaf morphology and Photosynthetic CharacteristicsThe statistical analysis of leaf morphology showed there was significant difference of leaf morphology in different habitats of A.mongolicus population.The leaf area,leaf thickness and petiole length of A.mongolicus were larger in sandy plots than that in gravel plots.The photosynthetic characteristics of A.mongolicus leave were different in different region and habitat.The photosynthetic rate of A.mongolicus were higher in sandy plots than that in gravel plots.The net photosynthetic rate of A.mongolicus in Alashan region was higher in experiments of the diurnal variation of photosynthesis and CO2 response.The net photosynthetic rate of A.mongolicus in Mengxi region was higher in experiments of light response.(3)Morphology and germination of seedsThe statistical analysis of seed morphology showed that there were significant differences in the traits of seeds collected in different region and habitat of A.mongolicus population.The sizes of seeds were smaller in gravel plots than that in sandy plots.The weights of seeds was relatively high in sandy plots.The imbibition rate and germination rate of seeds of A.mongolicus collected in this year were higher than that in the last year.The germination rate of seeds collected in Mengxi region was higher,but the surviving rate of young seedling was lower.The germination rate and surviving rate of samples in Zhongwei region were relatively higher.The imbibition rate and germination rate of samples in Alashan region were lower,but the surviving rate was relatively higher.