Studies On The Species Diversity And Environmental Relationship Of Bryophytes In Islands,Southern Fujian Province And Northern Guangdong Province,China

Nan?ao Island,Haishan North Island,Haishan South Island,Dongshan Island,and Dongshan Islet are located off the coast of Fujian Province and Guangdong Province.However,there has been a lack of relevant data and information in this area,including species composition,geographic composition,ecological characteristics,and environmental factors affecting the distribution of island bryophytes.1107 bryophyte specimens were collected from Nan?ao Island,Haishan South Island and Haishan North Island in Guangdong Province and Dongshan Island and Dongshan Islet in Fujian Province in May 2018.After systematic identification of the specimens,combined with field ecological data,species composition,flora composition and environmental factors affecting the composition,species number and distribution of bryophytes in the area were studied.The main results are as follows:1.The bryophytes of some islands in southern Fujian and northern Guangdong contain 121 species in 34 families and 59 genera.Among them,13 families,15 genera and 16 species of liverworts and 21 families,44 genera and 105 species of mosses.2.There are 6 dominant families of bryophytes,which are Pottiaceae,Hypnaceae,Bryaceae,Fissidentaceae,Pylaisiadelphaceae and Sematophyllaceae.Fissidens,Bryum,Hypnum,Barbula and Taxiphyllum are the main genera in the region.3.Total of 7 types of bryophyte habitats,including rock,stone-faced thin soil,soil,cement substrate,tree growth,decaying wood and dead wood pile,aquatic.The three major substrates of soil,rock and stone-faced thin soil account for 84.46%.It can be seen that the habitat in this area is relatively homogeneous,which largely limits the diversity of bryophytes.4.The bryophyte flora components of some islands in southern Fujian and northern Guangdong are complex and contain 8 major geographic components,among which the pan-tropical component ranks first,accounting for 22.64%,and East Asia ranks second,at 21.70%,and the north temperate component is in the third place,making up 18.87%.In this region,the Old World tropical component,the tropical Asian component and the pan-tropical component,constitute 40.56%of the total number of species,indicating that the region has a strong tropical coloration.5.The similarity of bryophytes among some islands in Fujian and Guangdong(including the five islands studied in this paper)is largely related to geographical locations,and islands with similar geographical locations generally have more similarities.In addition,some distant island bryophytes also share a certain degree of similarity,which may be caused by the long-distance spread of spores,rather than the formation of gradual diffusion.6.The number of bryophytes species in some islands in southern Fujian and northern Guangdong rose up gradually with the increase of area,maximum elevation and coastline length within a certain range.The functional relations are y=22.273e^0.0049x,R²=0.2929;y=0.0001x²+0.0866x+14.043,R²=0.9345;y=16.865e^0.0131x,R²=0.4551.7.2,4-Di-tert-butylphenol has a"low-promoted-high-inhibited"effect on the content of chlorophyll a in Haplocladium microphyllum(Sw.ex Hedw.)Broth..The low concentration of 2,4-di-tert-butylphenol can reduce the content of proline and malondialdehyde of Haplocladium microphyllum,while the high concentration of2,4-di-tert-butylphenol can increase the content of proline and malondialdehyde of Haplocladium microphyllum.