Study On Native And Exotic Weeds At Holgus Port And Surrounding Areas In Xinjiang

Horgos Port is the largest land border port in Xinjiang.The rapid development of port trade has aggravated the impact of human activities on the natural world,and the composition and distribution pattern of flora in this area are strongly disturbed by the external environment,especially the weed flora.Weeds are non-cultivated natural flora in an artificial environment and are constantly changing due to human and environmental influences.In the three years from 2016 to 2018,systematic field investigation and morphological taxonomy of native and exotic weeds were carried out at Horgos Port and its surrounding areas,and their species diversity and floristic characteristics were also analyzed,which provided new information for basic botanical research in Xinjiang and the region,as well as for the construction of ecological environment and the utilization of plant resources in the region.It provides a theoretical basis for plant inspection and quarantine at ports,as well as weed monitoring and control in agriculture,forestry and pasture.The results show that:1.There are 33 families,113 genera and 159 species of weeds in the Horgos port and surrounding areas in Xinjiang.There are only 1 family,1 genus and 1 species of pteridophytes,which account for 3.03%,0.88% and 0.63% of the total number of weeds,genera and species in this area.There are no gymnosperms,and angiosperms are the main species.There are altogether 158 species of 112 genera and 32 families,accounting for 96.97%,99.12% and 99.37% of the total number of weeds,genera and species in this area.Among them,138 species of dicotyledons belong to 95 genera and 30 families(accounting for 90.91%,84.07%,86.79% of the total number of weeds,genus and species),and 20 species of dicotyledons belong to 17 genera and 2 families(accounting for 6.06%,15.04%,12.58%).In the study area,a new record of alien invasive weeds,1 genera,was found,which is Galinsoga quadriradiata Ruiz et Pav.2.Composition characteristics of families:From the genus level of the family,there are 18 families and 18 genera in the single genera,10 families and 24 genera in oligogenous families with 2-6 genera,4 families and 45 genera in intermediate families with 6-19 genera,and 1 families and 26 genera in polygeneric families with more than 20 genera.Among them,there are 5 families of intermediate families and polygeneric families,including 71 genera,accounting for 62.83% of the total genera of weeds in this area,which is the main body of the district.From the level of the species level in the family,there are 16 families and 16 species in the single species,12 families and 43 species of oligospecies with 2-9 species,4 families and 62 species of intermediate families with 10-19 species,and only 38 species of multiple families with 20-49 species.Among them,there are 5 families of intermediate families and multiple families,including 100 species,accounting for 65.89% of the total number of weeds in this area.Their advantages are obvious.In summary,the single genera families(18 families,18 genera)and single species families(16 families,16 species)account for a high proportion in the family structure,accounting for about 1/2 of the total families,but the number of genera and species is very small;The middle families have 4 families(including 45 genera,62 species,about 1/8 of the total families),while the multi-genera families and multi-families have only 1 family(including 26 genera,38 species),respectively.Although there are only 5 families and many genera(multiple)families,there are 100 species in 71 genera,accounting for 62.83% and 62.89% of the total weed genera and species in this area.They are the dominant families in this area,including Compositae(26 genera/38 species),Graminae(16/19),Leguminosae(11/16),Cruciferae(11/14),Chenopodiaceae(7/13).3.Composition characteristics of genera:The structural composition of genus is relatively simple.There are only two types of genus,single genus and oligospecies with 2-6 species.There are not many genera and large genera.There are 84 species of 84 genera in a single species,accounting for 74.34% and 52.83% of the total number of weeds genera and species in the region;while 27 genera and 75 species belong to oligogenera,accounting for 25.66% and 47.17% of the total number of weed genera and species in this area.The proportion of single species in this area is very high,nearly 3/4,and the number of species is more than half,indicating that the genus is richer and the species is less abundant.Among them,the genera with relatively more species are Polygonum(6 species),Artemisia(5),and Chenopodium(4).4.There are 4 types of life forms,herbaceous plants account for the absolute dominance(156 species,accounting for 98.11%),of which 83 species(52.20%)are annual to biennial herbs,70 species(44.02%)are perennial herbs,and a few parasitic herbs(3 species,accounting for 1.89%)and semi-shrubs(3 species,accounting for 1.89%).5.There are three types of ecotypes,118 species of mesophytes,accounting for 74.21% of the total species;followed by hygrophytes,26 species,accounting for 16.35%;the least number of xerophytes,15 species,accounting for 9.44 %.6.Geographical characteristics of the flora: The distribution type of the weeds in the area is complex,with 8 distribution types and 8 variants,of which the Old World Temperate distribution and its variants are the largest type in the area(26 genera,accounting for 30.95%),the distribution of the North Temperate distribution and its variants are the second largest type(21 genera,accounting for 25%),and the Mediterranean distribution and its variants are the third largest type(16 genera,accounting for 19.05%).The geographical composition of this area has obvious temperate properties,and the genus with temperate nature has 48 genera,accounting for 57.14%.7.Among the 159 weeds in this study area,there are 156 native weeds.In recent ten years,Xanthium spinosa,Xanthium italicum and Galinsoga quadriradiata(newly recorded)were the exotic weeds newly invading Xinjiang and this area.Which are also malignant weeds.The quarantine weeds in this area are: Cuscuta australis,Cuscuta chinensis,Cuscuta monogyna,Xanthium spinosa,Xanthium italicum,Lactuca serriola,Aegilops tauschii and so on.For such malignant weeds and quarantine weeds,relevant departments must focus on monitoring and prevention.