OBJECTIVE To evaluate the in vivo anti-inflammatory and allergic rhinitis(AR)alleviating effect as well as in vitro antimicrobial activities of Artemisia ordosica Krasch.(AOK)extracts to verify its ethno-medicinal cla...OBJECTIVE To evaluate the in vivo anti-inflammatory and allergic rhinitis(AR)alleviating effect as well as in vitro antimicrobial activities of Artemisia ordosica Krasch.(AOK)extracts to verify its ethno-medicinal claims.METHODS Crude extracts(methanol/95%-ethanol/ethyl acetate)of AOK root/stem/leaf and fractions(petroleum ether/ethyl acetate/n-butanol/aqueous)of AOK root extractwere prepared.Xylene-induced ear swelling model in mouse and ovalbumin(OVA)-induced AR model in guinea pig were established.Ear swelling degrees of mice were measured.The numbers of rubbing movement and sneezes of guinea pigs were counted to evaluate the symptoms of AR.The serum levels of histamine,INF-γ,IL-2/4/10,and VCAM-1 were measured by ELISA assay.The histological changes of nasal mucosa were investigated by light microscope after H&E staining.Antimicrobial activities of AOK extracts were also tested.LC-MS/MS analysis was performed to characterize the constituents of active extract and molecular docking was conducted to predict the biological mechanism.RESULTS In ear-swelling model,extract(100.00 mg·kg^-1)from the ethyl acetate layer of 95%ethanol(100.00 mg·kg^-1)showed better swelling inhibition in mice than positive control(dexamethasone,191.91 mg·kg^-1).In AR model,extract from the ethyl acetate layer of 95%ethanol significantly alleviated the AR symp⁃toms in guinea pigs,decreased the serum levels of histamine,INF-γ,IL-2/4/10,and VCAM-1,and reduced the infiltration of eosinophil in nasal mucosa.For Staphylococcus aureus,the ethyl acetate extract of AOK stem showed the highest inhibi⁃tion(MIC=1.25 g·L^-1),for Escherichia coli,n-butanol layer of 95%ethanol extract of AOK root showed the highest inhibi⁃tion(MIC=15.00 g·L^-1),for Candida glabrata,95%-ethanol extract of AOK stem showed the best inhibition(MIC=0.064 g·L^-1),while ethyl acetate and n-butanol layers showed similar inhibition on MRSA(MIC=7.50 g·L-1).LC-MS/MS characteriza⁃tion showed that dicaffeoylquinic acids account for more than 30%of ethyl acetate layer of AOK extract.Dicaffeoylquinic acids bind with histamine-1 receptor with high affinities and interesting modes.CONCLUSION Extracts from AOK had interesting anti-inflammatory activity in mice,alleviating effect against OVA-induced AR in guinea pigs,and antimicrobial activities in vitro,which support the ethno-medicinal use of it.The main constituents in ethyl acetate layer of AOK root extract are dicaffeoylquinic acids and could bind with histamine-1 receptor well.These findings highlighted the impor⁃tance of natural product chemistry study of AOK.展开更多
Capillarin was isolated from Artemisia Ordosica Kraschen and characterized by IR, 1H-NMR, 13C-NMR, 1H-1HCOSY, HMQC, HMBC and EIMS, and its crystal structure was determined by single-crystal X-ray diffraction analysis ...Capillarin was isolated from Artemisia Ordosica Kraschen and characterized by IR, 1H-NMR, 13C-NMR, 1H-1HCOSY, HMQC, HMBC and EIMS, and its crystal structure was determined by single-crystal X-ray diffraction analysis with the following data: triclinic, space group P1, Z = 2, a = 7.226(6), b = 7.297(6), c = 11.042(8) ?, α = 74.695(12), β = 78.479(12), γ = 62.063(10)°, V = 494.2(6) ?3, Mr = 198.21, Dc = 1.332 g/cm3, F(000) = 208, μ = 0.089 mm-1, S = 1.023, (?/σ)max = 0.000, the final R = 0.0408 and wR = 0.1110. The largest peak and deepest hole on the final difference Fourier map are 0.219 and –0.161 e/?3, respectively. The bond lengths and bond angles of the molecule are also given.展开更多
Biomass and net primary productivity （NPP） are two important parameters in determining ecosystem carbon pool and carbon sequestration. The biomass storage and NPP in desert shrubland of Artemisia ordosica on Ordos P...Biomass and net primary productivity （NPP） are two important parameters in determining ecosystem carbon pool and carbon sequestration. The biomass storage and NPP in desert shrubland of Artemisia ordosica on Ordos Plateau were investigated with method of harvesting standard size shrub in the growing season （June-October） of 2006. Results indicated that above- and belowground biomass of the same size shrubs showed no significant variation in the growing season （p〉0.1）, but annual biomass varied significantly （p〈 0.01）. In the A. ordosica community, shrub biomass storage was 699.76-1246.40 g.m^-2 and annual aboveground NPP was 224.09 g-m^-2·a^-1. Moreover, shrub biomass and NPP were closely related with shrub dimensions （cover and height） and could be well predicted by shrub volume using power regression.展开更多
The diurnal and seasonal dynamics of soil respiration in the A. ordosica shrubland on Ordos Plateau were investigated in the growing season （May-October） of 2006 and their environmental driving factors were also ana...The diurnal and seasonal dynamics of soil respiration in the A. ordosica shrubland on Ordos Plateau were investigated in the growing season （May-October） of 2006 and their environmental driving factors were also analyzed, Results indicated that diurnal dynamics of soil respiration rate and its temperature dependence showed some discrepancy in two different growth stages （the vegetative growth stage and the reproductive growth stage）. During the vegetative growth stage, the diurnal variation of soil respiration was slight and not correlated with the daily temperature change, but during the reproductive growth stage, the daily respiration variation was relatively large and significantly correlated with the diurnal variation of air and soil temperature. In the growing season, the peak value of soil respiration occurred at July and August because of the better soil water-heat conditions and their optimal deployment in this period. In the shrubland ecosystem, precipitation was the switch of soil respiration pulses and can greatly increase soil respiration rates after soil rewetting. Moreover, the soil respiration rates in the growing season and the air temperature and soil surface water content were closely correlated （p〈0.05） each other. The stepwise regression model indicated that the variation of soil surface moisture accounted for 41.9% of the variation in soil respiration （p〈0.05）.展开更多
This study investigated the distribution pattern of biological soil crust （BSC） in Artemisia ordosica communities in Mu Us Sandy Land. Three experimental sites were selected according to grazing pressure gradient. I...This study investigated the distribution pattern of biological soil crust （BSC） in Artemisia ordosica communities in Mu Us Sandy Land. Three experimental sites were selected according to grazing pressure gradient. In each experimental site, the total vegetation cover, A. ordosica cover, BSC cover, litter-fall cover, BSC degree of fragmentation, BSC thickness and soil properties were investigated in both fixed and semi-fixed sand dunes and simultaneously analyzed in the laboratory. The results showed that at the same grazing pressure, BSC cover and composition were significantly affected by the fixation degree of sand dunes. In addition, BSC cover in the fixed sand dunes was 83.74% on average, whereas it is proportionally dominated by 28% mosses, 21% lichens, and 51% algae. Meanwhile, BSC cover in the semi-fixed sand dunes was 23.54% on average, which is proportionally domi- nated by 6.3% mosses, 2.5% lichens, and 91.2% algae. Fine sand, organic matter, and total nitrogen （N） contents in the fixed sand dunes were all significantly higher than those in the semi-fixed sand dunes. Litter-fall cover de- creased along the grazing pressure gradient, whereas BSC fragmentation degree increased. Fine sand content decreased along with the increase of grazing pressure, whereas medium sand content increased in both fixed and semi-fixed dunes. The organic matter and total N contents in the no grazing site were significantly higher than those in light and normal grazing sites. However, there were no significant differences between the light and normal grazing sites. In addition, there were also no significant differences in BSC thickness between the light and normal grazing sites in the fixed sand dunes. However, a significant decrease was observed in both BSC cover and thick- ness in the normal grazing site. The BSC in the semi-fixed dunes was more sensitive to disturbance.展开更多
The population density and distribution of the three major boring pests, Holcocerus artemisiae, Sphenoptera sp. and Adosopius sp. were studied in their host plant Artemisia ordosica. Results show that the larvae ofH. ...The population density and distribution of the three major boring pests, Holcocerus artemisiae, Sphenoptera sp. and Adosopius sp. were studied in their host plant Artemisia ordosica. Results show that the larvae ofH. artemisiae mainly bore the rhizome ofA. ordosica, but also the larvae of Sphenoptera sp. and Adosopius sp. bore the rhizome of A. ordosica. The adults of Sphenoptera sp. and Adosopius sp. feed on the leaves of A. ordosica as a nutritional supplement. The distribution of the larvae of three pests in their host plant is completely different. H. artemisiae and Sphenoptera sp. are distributed in the whole A. ordosica plant. The newly hatched larvae first feed on the phloem and xylem of stem and then burrow to the roots before the winter of the same year. However, ,4dosopius sp. is distributed mainly in the roots. The newly hatched larvae move from the phloem to the xylem, and gradually damage the lower part of the trunk. The larvae of the three pests sometimes coexist in a single A. ordosica plant. However, the probability of the coexistence of the three pests is very small. The highest probability of coexistence of two pests was observed in Sphenoptera sp. and H. artemisiae, while the probability of coexistence of Sphenoptera sp. and Adosopius sp. as well as H. artemisiae and Adosopius sp. was smaller. The reasons for coexistence or its avoidance are not only related to the amount of food provided nor the volume of larval living space in a single A. ordosica plant, but also related to the development characteristics of different kinds of larvae and interspecific competition.展开更多
Artemisia ordosica is an excellent sand-fixing shrub for sand stabilization in northwestern China. Sand dune stabilization, a critically important process, leads changes in abiotic factors, such as soil structure and ...Artemisia ordosica is an excellent sand-fixing shrub for sand stabilization in northwestern China. Sand dune stabilization, a critically important process, leads changes in abiotic factors, such as soil structure and nutrient contents. However, the effects of factors on an A. ordosica community following sand stabilization remain unclear. In this study, we used canonical correspondence analysis （CCA） to examine the relationships between A. ordosica communities and environmental factors at three habitats： semi-fixed dune （SF）, fixed dune with low-cov- erage biological soil crust （F）, and fixed dune with high- coverage biological soil crust （FC） in Mu Us desert. The mean height and coverage of plants increased with sand stabilization, while species diversity and richness increased initially and then reduced significantly. Correlation analysis and CCA revealed that slope, soil organic carbon, and nutrient contents, proportion of fine soil particles, soil moisture, and thickness of biological soil crust were all highly correlated with vegetation characteristics. These environmental factors could explain 40.42 % of the vege- tation-environment relationships at the three habitats. The distribution of plant species was positively related to soil moisture in the SF dune. Soil moisture, soil nutrient, and fine-particle contents mainly affected plants distribution in the F dune. In the FC dune, distribution of plant species was positively and negatively correlated with the thickness of biological soil crust and soil moisture at a depth 0-20 cm, respectively. The dominance value of typical steppe species increased significantly following sand-dune stabilization and relations between species and samples in CCA ordination bi-plots showed that perennial grasses could invade the A. ordosica community on FC, indicating A. ordosica communities had a tendency to change into typical steppe vegetation with the further fixation. We conclude that the significant differentiation not only occurred in community characteristics, but also in the relationships between vegetation and environmental factors among the three stages of dune fixation. So, restoration of degraded dune ecosystems should be based on habitat conditions and ecological needs.展开更多
Wind erosion is a key global environmental problem and has many adverse effects.The Mu Us Sandy Land of northern China is characterized by an arid climate,where vegetation patches and bare sand patches are usually dis...Wind erosion is a key global environmental problem and has many adverse effects.The Mu Us Sandy Land of northern China is characterized by an arid climate,where vegetation patches and bare sand patches are usually distributed mosaically,and aeolian activities occur frequently.Vegetation plays a significant role in controlling wind erosion.Artemisia ordosica is the most dominant native plant species in the Mu Us Sandy Land.It is urgent to study the wind-proof and sand-fixing effects of Artemisia ordosica in the Mu Us Sandy Land.This study analyzed the wind-proof and sand-fixing effects of Artemisia ordosica based on the field data of wind regimes,aeolian sediment transport,and surface change of Artemisia ordosica plots with four coverages(denoted as site A,site B,site C,and site D)in the Mu Us Sandy Land during the period from 1 June 2018 to 29 June 2019.The coverages of Artemisia ordosica at site A,site B,site C,and site D were 2%,16%,29%,and 69%,respectively.The annual average wind speeds at 2.0 m height above the ground for site A,site B,site C,and site D were 3.47,2.77,2.21,and 1.97 m/s,respectively.The annual drift potentials were 193.80,69.72,15.05,and 6.73 VU at site A,site B,site C,and site D,respectively.The total horizontal aeolian sediment fluxes during the period from 2-3 June 2018 to 6 June 2019 at site A,site B,site C,and site D were 4633.61,896.80,10.54,and 6.14 kg/m,respectively.Site A had the largest surface changes,and the surface changes at site B were significantly weaker than those at site A,whereas the surface changes at site C and site D were minimal.The results indicated that Artemisia ordosica significantly reduced the wind speed,drift potential,aeolian sediment transport,and surface changes.The higher the coverage of Artemisia ordosica is,the more obvious the effects of wind-proof and sand-fixing.Wind erosion would be effectively controlled in the Mu Us Sandy Land if the coverage of Artemisia ordosica is greater than 29%.These results provide a scientific basis for evaluating the ecosystem service function of Artemisia ordosica and the vegetation protection and construction projects in the Mu Us Sandy Land.展开更多
Plant phenotypic plasticity is a common feature that is crucial for explaining interspecific competition, dynamics and biological evolution of plant communities. In this study, we tested the effects of soil CaCO_3(cal...Plant phenotypic plasticity is a common feature that is crucial for explaining interspecific competition, dynamics and biological evolution of plant communities. In this study, we tested the effects of soil CaCO_3(calcium carbonate) on the phenotypic plasticity of a psammophyte, Artemisia ordosica, an important plant species on sandy lands in arid and semi-arid areas of China, by performing pot experiments under different CaCO_3 contents with a two-factor randomized block design and two orthogonal designs. We analyzed the growth responses(including plant height, root length, shoot-leaf biomass and root biomass) of A. ordosica seedlings to different soil CaCO_3 contents. The results revealed that, with a greater soil CaCO_3 content, A. ordosica seedlings gradually grew more slowly, with their relative growth rates of plant height, root length, shoot-leaf biomass and root biomass all decreasing significantly. Root N/P ratios showed significant negative correlations with the relative growth rates of plant height, shoot-leaf biomass and root length of A. ordosica seedlings; however, the relative growth rate of root length increased significantly with the root P concentration increased, showing a positive correlation. These results demonstrate that soil CaCO_3 reduces the local P availability in soil, which produces a non-adaptive phenotypic plasticity to A. ordosica seedlings. This study should prove useful for planning and promoting the restoration of damaged/degraded vegetation in arid and semi-arid areas of China.展开更多
基金Science Foundation of Inner Mongolia(2017MS0870)Science and Technology Planning Project of Inner Mongolia(201702139)
文摘OBJECTIVE To evaluate the in vivo anti-inflammatory and allergic rhinitis(AR)alleviating effect as well as in vitro antimicrobial activities of Artemisia ordosica Krasch.(AOK)extracts to verify its ethno-medicinal claims.METHODS Crude extracts(methanol/95%-ethanol/ethyl acetate)of AOK root/stem/leaf and fractions(petroleum ether/ethyl acetate/n-butanol/aqueous)of AOK root extractwere prepared.Xylene-induced ear swelling model in mouse and ovalbumin(OVA)-induced AR model in guinea pig were established.Ear swelling degrees of mice were measured.The numbers of rubbing movement and sneezes of guinea pigs were counted to evaluate the symptoms of AR.The serum levels of histamine,INF-γ,IL-2/4/10,and VCAM-1 were measured by ELISA assay.The histological changes of nasal mucosa were investigated by light microscope after H&E staining.Antimicrobial activities of AOK extracts were also tested.LC-MS/MS analysis was performed to characterize the constituents of active extract and molecular docking was conducted to predict the biological mechanism.RESULTS In ear-swelling model,extract(100.00 mg·kg^-1)from the ethyl acetate layer of 95%ethanol(100.00 mg·kg^-1)showed better swelling inhibition in mice than positive control(dexamethasone,191.91 mg·kg^-1).In AR model,extract from the ethyl acetate layer of 95%ethanol significantly alleviated the AR symp⁃toms in guinea pigs,decreased the serum levels of histamine,INF-γ,IL-2/4/10,and VCAM-1,and reduced the infiltration of eosinophil in nasal mucosa.For Staphylococcus aureus,the ethyl acetate extract of AOK stem showed the highest inhibi⁃tion(MIC=1.25 g·L^-1),for Escherichia coli,n-butanol layer of 95%ethanol extract of AOK root showed the highest inhibi⁃tion(MIC=15.00 g·L^-1),for Candida glabrata,95%-ethanol extract of AOK stem showed the best inhibition(MIC=0.064 g·L^-1),while ethyl acetate and n-butanol layers showed similar inhibition on MRSA(MIC=7.50 g·L-1).LC-MS/MS characteriza⁃tion showed that dicaffeoylquinic acids account for more than 30%of ethyl acetate layer of AOK extract.Dicaffeoylquinic acids bind with histamine-1 receptor with high affinities and interesting modes.CONCLUSION Extracts from AOK had interesting anti-inflammatory activity in mice,alleviating effect against OVA-induced AR in guinea pigs,and antimicrobial activities in vitro,which support the ethno-medicinal use of it.The main constituents in ethyl acetate layer of AOK root extract are dicaffeoylquinic acids and could bind with histamine-1 receptor well.These findings highlighted the impor⁃tance of natural product chemistry study of AOK.
基金The project was supported by Henan Innovation Project for University Prominent Research Talents (2004)
文摘Capillarin was isolated from Artemisia Ordosica Kraschen and characterized by IR, 1H-NMR, 13C-NMR, 1H-1HCOSY, HMQC, HMBC and EIMS, and its crystal structure was determined by single-crystal X-ray diffraction analysis with the following data: triclinic, space group P1, Z = 2, a = 7.226(6), b = 7.297(6), c = 11.042(8) ?, α = 74.695(12), β = 78.479(12), γ = 62.063(10)°, V = 494.2(6) ?3, Mr = 198.21, Dc = 1.332 g/cm3, F(000) = 208, μ = 0.089 mm-1, S = 1.023, (?/σ)max = 0.000, the final R = 0.0408 and wR = 0.1110. The largest peak and deepest hole on the final difference Fourier map are 0.219 and –0.161 e/?3, respectively. The bond lengths and bond angles of the molecule are also given.
基金National Natural Sciences Foundation of China (Nos. 40501072 and 40673067)the Major State Basic Research Develop-ment Program of China (No. 2002CB 412503)the Knowledge In-novation Program of the Institute of Geographic Sciences and Natural Resources Research,CAS "The effect of human activities on regional envi-ronmental quality, the health risk and the environmental remediation"
文摘Biomass and net primary productivity （NPP） are two important parameters in determining ecosystem carbon pool and carbon sequestration. The biomass storage and NPP in desert shrubland of Artemisia ordosica on Ordos Plateau were investigated with method of harvesting standard size shrub in the growing season （June-October） of 2006. Results indicated that above- and belowground biomass of the same size shrubs showed no significant variation in the growing season （p〉0.1）, but annual biomass varied significantly （p〈 0.01）. In the A. ordosica community, shrub biomass storage was 699.76-1246.40 g.m^-2 and annual aboveground NPP was 224.09 g-m^-2·a^-1. Moreover, shrub biomass and NPP were closely related with shrub dimensions （cover and height） and could be well predicted by shrub volume using power regression.
基金National Natural Sciences Foundation of China (Nos.40501072 and 40673067)the Major State Basic Research Develop-ment Program of China (No.2002CB 412503)the Knowledge Inno-vation Program of the Institute of Geographic Sciences and Natural Re-sources Research,CAS "The effect of human activities on regional envi-ronmental quality,the health risk and the environmental remediation"
文摘The diurnal and seasonal dynamics of soil respiration in the A. ordosica shrubland on Ordos Plateau were investigated in the growing season （May-October） of 2006 and their environmental driving factors were also analyzed, Results indicated that diurnal dynamics of soil respiration rate and its temperature dependence showed some discrepancy in two different growth stages （the vegetative growth stage and the reproductive growth stage）. During the vegetative growth stage, the diurnal variation of soil respiration was slight and not correlated with the daily temperature change, but during the reproductive growth stage, the daily respiration variation was relatively large and significantly correlated with the diurnal variation of air and soil temperature. In the growing season, the peak value of soil respiration occurred at July and August because of the better soil water-heat conditions and their optimal deployment in this period. In the shrubland ecosystem, precipitation was the switch of soil respiration pulses and can greatly increase soil respiration rates after soil rewetting. Moreover, the soil respiration rates in the growing season and the air temperature and soil surface water content were closely correlated （p〈0.05） each other. The stepwise regression model indicated that the variation of soil surface moisture accounted for 41.9% of the variation in soil respiration （p〈0.05）.
基金Funding was provided by the National Key Technology R&DP rogram (2012BAD16B01)the Special Research Program for Public-welfare Forestry of China (201104077)the National Natural Science Foundation of China (31170667)
文摘This study investigated the distribution pattern of biological soil crust （BSC） in Artemisia ordosica communities in Mu Us Sandy Land. Three experimental sites were selected according to grazing pressure gradient. In each experimental site, the total vegetation cover, A. ordosica cover, BSC cover, litter-fall cover, BSC degree of fragmentation, BSC thickness and soil properties were investigated in both fixed and semi-fixed sand dunes and simultaneously analyzed in the laboratory. The results showed that at the same grazing pressure, BSC cover and composition were significantly affected by the fixation degree of sand dunes. In addition, BSC cover in the fixed sand dunes was 83.74% on average, whereas it is proportionally dominated by 28% mosses, 21% lichens, and 51% algae. Meanwhile, BSC cover in the semi-fixed sand dunes was 23.54% on average, which is proportionally domi- nated by 6.3% mosses, 2.5% lichens, and 91.2% algae. Fine sand, organic matter, and total nitrogen （N） contents in the fixed sand dunes were all significantly higher than those in the semi-fixed sand dunes. Litter-fall cover de- creased along the grazing pressure gradient, whereas BSC fragmentation degree increased. Fine sand content decreased along with the increase of grazing pressure, whereas medium sand content increased in both fixed and semi-fixed dunes. The organic matter and total N contents in the no grazing site were significantly higher than those in light and normal grazing sites. However, there were no significant differences between the light and normal grazing sites. In addition, there were also no significant differences in BSC thickness between the light and normal grazing sites in the fixed sand dunes. However, a significant decrease was observed in both BSC cover and thick- ness in the normal grazing site. The BSC in the semi-fixed dunes was more sensitive to disturbance.
基金supported by the National Project of ScienceTechnology for the 11th Five-Year Plan in China (Grant No. 2006BAD08A1001)the Program for Changjiang Scholars and Innovative Research Team in Universities (PCSIRT0607)
文摘The population density and distribution of the three major boring pests, Holcocerus artemisiae, Sphenoptera sp. and Adosopius sp. were studied in their host plant Artemisia ordosica. Results show that the larvae ofH. artemisiae mainly bore the rhizome ofA. ordosica, but also the larvae of Sphenoptera sp. and Adosopius sp. bore the rhizome of A. ordosica. The adults of Sphenoptera sp. and Adosopius sp. feed on the leaves of A. ordosica as a nutritional supplement. The distribution of the larvae of three pests in their host plant is completely different. H. artemisiae and Sphenoptera sp. are distributed in the whole A. ordosica plant. The newly hatched larvae first feed on the phloem and xylem of stem and then burrow to the roots before the winter of the same year. However, ,4dosopius sp. is distributed mainly in the roots. The newly hatched larvae move from the phloem to the xylem, and gradually damage the lower part of the trunk. The larvae of the three pests sometimes coexist in a single A. ordosica plant. However, the probability of the coexistence of the three pests is very small. The highest probability of coexistence of two pests was observed in Sphenoptera sp. and H. artemisiae, while the probability of coexistence of Sphenoptera sp. and Adosopius sp. as well as H. artemisiae and Adosopius sp. was smaller. The reasons for coexistence or its avoidance are not only related to the amount of food provided nor the volume of larval living space in a single A. ordosica plant, but also related to the development characteristics of different kinds of larvae and interspecific competition.
基金supported by the National Basic Research Program of P.R.China(973 Program,2013CB429901)the Fundamental Research Funds for the Central Universities of P.R.China(BJFU-TD2011-04)National Technology and Science Support Program of P.R.China(2012BAD16B02)
文摘Artemisia ordosica is an excellent sand-fixing shrub for sand stabilization in northwestern China. Sand dune stabilization, a critically important process, leads changes in abiotic factors, such as soil structure and nutrient contents. However, the effects of factors on an A. ordosica community following sand stabilization remain unclear. In this study, we used canonical correspondence analysis （CCA） to examine the relationships between A. ordosica communities and environmental factors at three habitats： semi-fixed dune （SF）, fixed dune with low-cov- erage biological soil crust （F）, and fixed dune with high- coverage biological soil crust （FC） in Mu Us desert. The mean height and coverage of plants increased with sand stabilization, while species diversity and richness increased initially and then reduced significantly. Correlation analysis and CCA revealed that slope, soil organic carbon, and nutrient contents, proportion of fine soil particles, soil moisture, and thickness of biological soil crust were all highly correlated with vegetation characteristics. These environmental factors could explain 40.42 % of the vege- tation-environment relationships at the three habitats. The distribution of plant species was positively related to soil moisture in the SF dune. Soil moisture, soil nutrient, and fine-particle contents mainly affected plants distribution in the F dune. In the FC dune, distribution of plant species was positively and negatively correlated with the thickness of biological soil crust and soil moisture at a depth 0-20 cm, respectively. The dominance value of typical steppe species increased significantly following sand-dune stabilization and relations between species and samples in CCA ordination bi-plots showed that perennial grasses could invade the A. ordosica community on FC, indicating A. ordosica communities had a tendency to change into typical steppe vegetation with the further fixation. We conclude that the significant differentiation not only occurred in community characteristics, but also in the relationships between vegetation and environmental factors among the three stages of dune fixation. So, restoration of degraded dune ecosystems should be based on habitat conditions and ecological needs.
基金the Fundamental Research Funds of Chinese Academy of Forestry(CAFYBB2019MA009)the National Natural Science Foundation of China(41701010)+1 种基金the Key Special Project on'Science and Technology Promoting the Development of Inner Mongolia Autonomous Region'(KJXM-EEDS-2020006)the Youth Innovation Promotion Association of Chinese Academy of Sciences(2018459)。
文摘Wind erosion is a key global environmental problem and has many adverse effects.The Mu Us Sandy Land of northern China is characterized by an arid climate,where vegetation patches and bare sand patches are usually distributed mosaically,and aeolian activities occur frequently.Vegetation plays a significant role in controlling wind erosion.Artemisia ordosica is the most dominant native plant species in the Mu Us Sandy Land.It is urgent to study the wind-proof and sand-fixing effects of Artemisia ordosica in the Mu Us Sandy Land.This study analyzed the wind-proof and sand-fixing effects of Artemisia ordosica based on the field data of wind regimes,aeolian sediment transport,and surface change of Artemisia ordosica plots with four coverages(denoted as site A,site B,site C,and site D)in the Mu Us Sandy Land during the period from 1 June 2018 to 29 June 2019.The coverages of Artemisia ordosica at site A,site B,site C,and site D were 2%,16%,29%,and 69%,respectively.The annual average wind speeds at 2.0 m height above the ground for site A,site B,site C,and site D were 3.47,2.77,2.21,and 1.97 m/s,respectively.The annual drift potentials were 193.80,69.72,15.05,and 6.73 VU at site A,site B,site C,and site D,respectively.The total horizontal aeolian sediment fluxes during the period from 2-3 June 2018 to 6 June 2019 at site A,site B,site C,and site D were 4633.61,896.80,10.54,and 6.14 kg/m,respectively.Site A had the largest surface changes,and the surface changes at site B were significantly weaker than those at site A,whereas the surface changes at site C and site D were minimal.The results indicated that Artemisia ordosica significantly reduced the wind speed,drift potential,aeolian sediment transport,and surface changes.The higher the coverage of Artemisia ordosica is,the more obvious the effects of wind-proof and sand-fixing.Wind erosion would be effectively controlled in the Mu Us Sandy Land if the coverage of Artemisia ordosica is greater than 29%.These results provide a scientific basis for evaluating the ecosystem service function of Artemisia ordosica and the vegetation protection and construction projects in the Mu Us Sandy Land.
基金supported by the National Key Research and Development Program of China (2016YFC0500706)
文摘Plant phenotypic plasticity is a common feature that is crucial for explaining interspecific competition, dynamics and biological evolution of plant communities. In this study, we tested the effects of soil CaCO_3(calcium carbonate) on the phenotypic plasticity of a psammophyte, Artemisia ordosica, an important plant species on sandy lands in arid and semi-arid areas of China, by performing pot experiments under different CaCO_3 contents with a two-factor randomized block design and two orthogonal designs. We analyzed the growth responses(including plant height, root length, shoot-leaf biomass and root biomass) of A. ordosica seedlings to different soil CaCO_3 contents. The results revealed that, with a greater soil CaCO_3 content, A. ordosica seedlings gradually grew more slowly, with their relative growth rates of plant height, root length, shoot-leaf biomass and root biomass all decreasing significantly. Root N/P ratios showed significant negative correlations with the relative growth rates of plant height, shoot-leaf biomass and root length of A. ordosica seedlings; however, the relative growth rate of root length increased significantly with the root P concentration increased, showing a positive correlation. These results demonstrate that soil CaCO_3 reduces the local P availability in soil, which produces a non-adaptive phenotypic plasticity to A. ordosica seedlings. This study should prove useful for planning and promoting the restoration of damaged/degraded vegetation in arid and semi-arid areas of China.
