Study On Classification And Environmental Adaptability Of Bryophyte In Mu Us Sandy Land

Mu Us Sandy Land is the most located in the northwest of the four sandy lands,close to the desert area,belonging to the typical temperate continental semi-arid monsoon climate.In the past studies,community layers and distribution patterns were investigated on a large scale.However,there are no studies on the classification,ecological amplitude of water,morphological adaptability of drought tolerance and the distribution of bryophyte species on a small scale in the Mu Us Sandy Land.Therefore,it is of great ecological significance to study the taxonomy of bryophytes and their adaptability to the environment in Mu Us Sandy Land,where the vegetation types are complex and diverse,the ecological environment is sensitive and the regional ecological function is remarkable.The main results of this study are as follows:(1)More than 310 specimens collected in Mu Us Sandy Land were identified,including 16 families,32 genera and 75 species(including varieties),3 families,3 genera and 6 species of liverworts,and 13 families,29 genera and 69 species of mosses.Among the families with more species were Pottiaceae(12 genera,29 species),Amblystegiaceae,(4 genera,12 species),Bryaceae(2 genera,10 species).The genera with more species were Biyum(9 species),Didymodon(8 species),Drepanocladus(6 species),Barbula(4 species),Amblystegium(4 species).At the same time,an index table of families,genera and species was compiled,and the main morphological characteristics of families,genera and species were described.The morphological and anatomical maps of all species,as well as the records of specimen numbers,distribution areas and habitats were provided.(2)The 75 bryophytes can be divided into 10 growth forms:The liverworts were divided into 4 growth forms,including Small cormus hepaticae(1 species),Small thallus hepaticae(2 species).Medium thallus hepaticae(2 species),and Large cormus hepaticae(1 species).The mosses were divided into 6 growth forms,including Small acrocarpri-musconun(22 species),Medium heigght acrocarpri-musconun(22 species),Large acrocarpri-muscorum(3 species),Small pleurocarpri-muscorum(10 species),Medium pleurocarpri-musconum(4 species),and Large pleurocarpri-musconum(8 species).According to the distribution of bryophytes in the study area,the 75 bryophytes can be preliminarily divided into the following types of water ecological amplitude.The liverworts is divided into ? meso-xerophytic—xero-mesophytic(1 species),?meso-xerophytic—mesophytic(2 species),? xero-mesophytic—mesophytic(1 species)and ? mesophytic(2 species).The Acrocarpri-musconum is divided into ? xerophytic(1 species),? xerophytic—meso-xerophytic(1 species),?meso-xerophytic(1 species),? xerophytic—xero-mesophytic(2 species),?xerophytic—mesophytic(4 species),?meso-xerophytic—mesophytic(4 species),? xerophytic—hygro-mesophytic(2 species),? xero-mesophytic—mesophytic(7 species),?mesophytic(12 species),? xero-mesophytic—hygro-mesophytic(2 species),(11)mesophytic—hygro-mesophytic(8 species),(12)hygro-mesophytic—hygrophytic(3 species).The Pleurocarpri-muscorum is divided into ? mesophytic(8 species),? mesophytic—hygro-mesophytic(2 species),? mesophytic—hygrophytic(1 species),?hygro-mesophytic—hygrophytic(3 species),?hygrophytic(8 species).The frequency of water ecological amplitude of the 75 bryophytes was 10 times in the xerophytic habitat,17 times in the meso-xerophytic habitat,25 times in the xero-mesophytic habitat,55 times in the mesophytic habitat,21 times in the hygro-mesophytic habitat,and 15 times in the hjygrophytic habitat.(3)In general,the four mosses and eight mosses have the morphological characteristics of water retention and absorption and drought adaptation.Mannia triandra and Mannia sibirica are covered with imbricate scales,which can effectively reduce the damage to the plant body caused by sunlight.Riccia Albolimbata is grayish-white and reflects sunlight;Riccia Sorocarpa foliates are nearly as thick as they are wide,reducing the surface area exposed to air.Colorless transparent cells on the surface of the nutrient filaments reflect light and reduce the ability to evaporate water.Bryum argenteum has no chloroplasts in the upper leaves and is colorless and transparent,which enhances the reflection effect.Crossidium chloronotos,Pterygoneurum subsessile and Aloina rigida have green filamentes or ctenoids that are specialized for photosynthesis.Green fimbrium moss and salinotrichum moss have slender transparent hairs that reflect light and retain water.(4)Canonical Correspondence Analysis(CCA)shows that the main environmental factors affecting the distribution of bryophytes in Sabina Vulgaris shrub were light intensity,litter coverage,air humidity,soil moisture and habitat type.The environmental factors influencing the distribution of bryophytes in Artemisia ordosica semi-shrub were light intensity,habitat type,herbaceous coverage,litter coverage,microtopography and air humidity The main environmental factors affecting thie distribution of bryophytes in the desert canyon include slope,litter coverage,substrate stability,substrate type and microtopography.Diffrent plots and species distribution patterns reflected the environmental differences of different microhabitats.