Sand Fixation And Population Regeneration Ability Of Several Desert Plants In Southern Xinjiang,China

Southern Xinjiang?South of Tianshan,Xinjiang?is one of the most severe soil desertification,obvious desert flow,and less desert vegetation areas in China.The role of research in the region has important scientific significance and practical application value for maintaining the stability of desert and oasis edge ecosystems,species diversity protection and environmental restoration,which desert plants in sand prevention and sand fixation,population renewal capacity and protection forest construction.In this paper,the desert grassland of Atushi Gdalian was selected as the research area,and the sand fixation ability of desert plants in this area was evaluated by using field and indoor control experiments;Nitraria sphaerocarpa Maxim and Calligonum roborovskii Losinskaja's was the dominant species in the community,temporal and spatial dynamics of sand-fixing capacity,seed dormancy and germination characteristics have been preliminarily studied in order to find out the funtion of sand-fixing and renewal of dominant species in the region.The main results are as follows:1.There are 27 species of 15 families and 21 genus of desert plants in the region;Nitraria sphaerocarpa Maxim,Calligonum roborovskii,Tamarix ramosissima Ledeb,Convolvulus fruticosus Pall,Pegasum harmala L,Hexinia polydichotoma?Ostenf.?HLYang)and Zygophyllum potaninii Maxim have certain sand-fixing ability.There are significant differences in the density and frequency of different plants in the two habitats;among them,the frequency of Nitraria sphaerocarpa,Calligonum roborovskii,Hexinia polydichotoma?Ostenf.?H.L.Yang and Peganum harmala L are higher than other species.There was a positive correlation between the crown area of plants and the volume of sand dunes.Among them,the crown area of Nitraria sphaerocarpa,Calligonum roborovskii,Hexinia polydichotoma?Ostenf.?H.L.Yang and Peganum harmala L,had a strong correlation with the volume of sand dunes.The establishment of mixed shelterbelts in this area with grassy woody plants such as Tamarix ramosissima,Nitraria sphaerocarpa,Calligonum roborovskii,Hexinia polydichotoma?Ostenf.?H.L.Yang and Peganum harmala L can achieve better sand control and sand fixation effects.2.There is a clear difference between the phenological characteristics of the two plants in the surface habitats of gravel and soil texture;The germination of the jujube of the tarim sand is earlier than that of the thorn fruit among them.At the same time,the germination time of the same species in the gravel surface habitat was earlier than that of the soil texture surface habitat.There is a significant difference in the dune volume?sand-fixing capacity?of the two plants in different months.The dune volume of the two plants in summer is stronger than that in other seasons;The positive sand-fixing capacity in different seasons is related to wind speed,but not related to precipitation.In addition,there are significant differences between the proportions of the dynamic changes of dune volume in different years for the fruit of N.sphaerocarpa and C.roborovskii.The sand-fixing ability of the N.sphaerocarpa is stronger than that of C.roborovskii.3.There were significant differences in fruit color,size,weight and length of prickle hairs at different storage times.The time when the whole fruit floats on the surface of the water and the water diffusion capacity associated with the amount of water absorption is stronger than the fruit from which the bristles are removed.The diffusion distance of intact fruit at 1 m/s and 4 m/s wind speed is longer than that of non-bristled fruit.There is a significantly difference between germination rate of intact and fruits without bristles at 20?/30?under light and dark conditions at 10mmol/L concentration of AG₃ and different dry storage times;among germination rate of fruits without bristles higher than that of intact fruits in each treatment.Outdoor potted experiments show that,the fruit bristles of this species have inhibitory effect on seed germination.In addition,the fruit bristles of Calligonum roborowskii.have an important effect on the dispersal and germination characteristics of this species and population renewal in the desert environment on the edge of the Taklamakan desert.4.There is a significant difference between the germination rate of N.sphaerocarpa seeds under light and dark conditions;The germination rate under dark conditions is higher than that under light conditions.There was a significant difference in the germination rate of seeds under different temperature conditions?p<0.01?,in which the germination rate of fruits at 10/20?was higher than that at other temperatures.The germination rate of seeds refrigerated for 3 months and 6months is higher than that of unrefrigerated seeds.Low temperature stratification can promote the germination rate of seeds.Under the temperature condition of 10/20?,the germination rate of seeds treated with 1 mmol/L and 10 mmol/LGA₃ is high,and gibberellin can promote seed germination;The species has neutral physiological dormancy,which can be broken by low temperature stratification and gibberellin Sleep.In the pot experiment,the germination rate of seeds in the dark environment was higher than that in the light environment;In addition,the temperature drop caused the seedlings to die.The physiological dormancy of the seeds of N.sphaerocarpa can affect the population renewal ability of the species.