Minimum temperatures have remarkable impacts on tree growth at high-elevation sites on the Tibetan Plateau,but the shortage of long-term and high-resolution paleoclimate records inhibits understanding of recent minimu...Minimum temperatures have remarkable impacts on tree growth at high-elevation sites on the Tibetan Plateau,but the shortage of long-term and high-resolution paleoclimate records inhibits understanding of recent minimum temperature anomalies.In this study,a warm season(April–September)reconstruction is presented for the past 467 years(1550–2016)based on Sabina tibetica ring-width chronology on the Lianbaoyeze Mountain of the central eastern Tibetan Plateau.Eight warm periods and eight cold periods were identified.Long-term minimum temperature variations revealed a high degree of coherence with nearby reconstructions.Spatial correlations between our reconstruction and global sea surface temperatures suggest that warm season minimum temperature anomalies in the central eastern Tibetan Plateau were strongly influenced by large-scale ocean atmospheric circulations,such as the El Ni?o-Southern Oscillation and the Atlantic Multidecadal Oscillation.展开更多
Vegetation restoration through artificial plantation is an effective method to combat desertification,especially in arid and semi-arid areas.This study aimed to explore the ecological effect of the plantation of Sabin...Vegetation restoration through artificial plantation is an effective method to combat desertification,especially in arid and semi-arid areas.This study aimed to explore the ecological effect of the plantation of Sabina vulgaris on soil physical and chemical properties on the southeastern fringe of the Mu Us Sandy Land,China.We collected soil samples from five depth layers(0-20,20-40,40-60,60-80,and 80-100 cm)in the S.vulgaris plantation plots across four plantation ages(4,7,10,and 16 years)in November 2019,and assessed soil physical(soil bulk density,soil porosity,and soil particle size)and chemical(soil organic carbon(SOC),total nitrogen(TN),available nitrogen(AN),available phosphorus(AP),available potassium(AK),cation-exchange capacity(CEC),salinity,p H,and C/N ratio)properties.The results indicated that the soil predominantly consisted of sand particles(94.27%-99.67%),with the remainder being silt and clay.As plantation age increased,silt and very fine sand contents progressively rose.After 16 years of planting,there was a marked reduction in the mean soil particle size.The initial soil fertility was low and declined from 4 to 10 years of planting before witnessing an improvement.Significant positive correlations were observed for the clay,silt,and very fine sand(mean diameter of 0.000-0.100 mm)with SOC,AK,and p H.In contrast,fine sand and medium sand(mean diameter of 0.100-0.500 mm)showed significant negative correlations with these indicators.Our findings ascertain that the plantation of S.vulgaris requires 10 years to effectively act as a windbreak and contribute to sand fixation,and needs 16 years to improve soil physical and chemical properties.Importantly,these improvements were found to be highly beneficial for vegetation restoration in arid and semi-arid areas.This research can offer valuable insights for the protection and restoration of the vegetation ecosystem in the sandy lands in China.展开更多
The antibacterial effects of waste liquor of essence oil extraction from Sabina vulgaris Ant on Escherichia coil, Staphylococcus aureus, Salmonella, Bacillus subtilis, Bacillus magaterium and Bacillus cereus in foods ...The antibacterial effects of waste liquor of essence oil extraction from Sabina vulgaris Ant on Escherichia coil, Staphylococcus aureus, Salmonella, Bacillus subtilis, Bacillus magaterium and Bacillus cereus in foods were evaluated by paper disk method. The results showed that the waste liquor of essence oil extraction from S. vulgaris had inhibitory effects on E. coil, S. aureus and Salmonella with bet- ter inhibitory effects on E. coil and Salmonella; the bacteriostatic effect of water steam distillation waste liquor was better than that of water extraction waste liquor. The more times the waste liquor was distilled, the higher the active ingredients content was, and the better the bacteriostatic effect was.展开更多
duniperus sabina Linnaeus, an evergreen shrub with prostrate life form, can effectively prevent sand moving and is an important tree species for reforestation in semiarid areas of China. It has laterally distributed a...duniperus sabina Linnaeus, an evergreen shrub with prostrate life form, can effectively prevent sand moving and is an important tree species for reforestation in semiarid areas of China. It has laterally distributed adventitious roots and a deeply distributed main root system. To detect water movement between the main root system and adventitious roots, we adopted heat pulse sensors using the Heat Ratio Method, a high precision method for measuring low sap flow rates. Two sensors were implanted in each individual in the stem between the main root system and adventitious roots, and another two in lateral stems distal to all the roots. Positive sap flows during nighttime, even under saturated air moisture conditions, were detected only between the main root system and adventitious roots under drought conditions, and the rate of flow increased as drought progressed and decreased or disappeared after rain events. The results demonstrated the existence of water movement from the main root system to adventitious roots, and combined with the high contribution of nighttime sap flow to transpiration （11%-16%） the results indicate that it also involves the process of hydraulic lift, a water movement from moist subsoil to dry surface soils. Integrated water use strategy between the main root system and adventitious roots via the process of hydraulic lift of soil water maximizes water acquisition efficiency from both subsoil water and water from rain pulses on the soil surface; this increases survivability in the water-limited environment of semiarid areas.展开更多
Seasonal variation of foliar δ13C values as well as proline, silicon, MDA and relative water content in Sabina przewalskii Kom. and S. chinensis （Lin.） Ant. were measured. The results show that foliar δ13C values ...Seasonal variation of foliar δ13C values as well as proline, silicon, MDA and relative water content in Sabina przewalskii Kom. and S. chinensis （Lin.） Ant. were measured. The results show that foliar δ13C values were significantly different at different seasons： lower in winter but higher in summer. δ13C values were positively correlated with air temperature and soil temperature. This demonstrates that foliar δ13C of Sabina is a successful empirical indictor of temperature. Furthermore, foliar δ13C values were positively related to proline and silicon content, and negatively related to relative water content and MDA content. Compared with S. chinensis, S. przewalskii has higher δ13C values, proline and silicon content as well as lower MDA and relative water content. All these results provided strong evidence that it is feasible for δ13C to be regarded as another index to evaluate freezing tolerance of Sabina.展开更多
This study presents an analysis of magnetic susceptibility and natural gamma radioactivity as indirect indicators of impurities in Cretaceous limestones of the Sabinas basin, as well as of the possible relation of the...This study presents an analysis of magnetic susceptibility and natural gamma radioactivity as indirect indicators of impurities in Cretaceous limestones of the Sabinas basin, as well as of the possible relation of these physical properties with the changes in the sedimentation environment. Both of these physical properties indicate changes in the degree of impurities and the mineralogical composition of this rock, principally in its organic matter and detritus content. Considering that the sedimentation environment determines the impurities in these rocks, possible environmental conditions at different levels of the Cretaceous were suggested using the magnetic susceptibility, total gamma radiation and potassium values, as well as the uranium and thorium concentration in the limestones. The analyses suggest variations in the depth of water table of the basin, which are mainly related to transgressions and marine regressions.展开更多
基金funded by the National Key Research and Development Program of China(No.2018YFA0605601)Hong Kong Research Grants Council(No.106220169)+1 种基金the National Natural Science Foundation of China(No.42105155,41671042,and 42077417)the National Geographic Society(No.EC-95776R-22)。
文摘Minimum temperatures have remarkable impacts on tree growth at high-elevation sites on the Tibetan Plateau,but the shortage of long-term and high-resolution paleoclimate records inhibits understanding of recent minimum temperature anomalies.In this study,a warm season(April–September)reconstruction is presented for the past 467 years(1550–2016)based on Sabina tibetica ring-width chronology on the Lianbaoyeze Mountain of the central eastern Tibetan Plateau.Eight warm periods and eight cold periods were identified.Long-term minimum temperature variations revealed a high degree of coherence with nearby reconstructions.Spatial correlations between our reconstruction and global sea surface temperatures suggest that warm season minimum temperature anomalies in the central eastern Tibetan Plateau were strongly influenced by large-scale ocean atmospheric circulations,such as the El Ni?o-Southern Oscillation and the Atlantic Multidecadal Oscillation.
基金funded by the National Natural Science Foundation of China(42171004)the Key Research and Development Program in Shaanxi Province,China(2021ZDLSF05-02)the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0403)。
文摘Vegetation restoration through artificial plantation is an effective method to combat desertification,especially in arid and semi-arid areas.This study aimed to explore the ecological effect of the plantation of Sabina vulgaris on soil physical and chemical properties on the southeastern fringe of the Mu Us Sandy Land,China.We collected soil samples from five depth layers(0-20,20-40,40-60,60-80,and 80-100 cm)in the S.vulgaris plantation plots across four plantation ages(4,7,10,and 16 years)in November 2019,and assessed soil physical(soil bulk density,soil porosity,and soil particle size)and chemical(soil organic carbon(SOC),total nitrogen(TN),available nitrogen(AN),available phosphorus(AP),available potassium(AK),cation-exchange capacity(CEC),salinity,p H,and C/N ratio)properties.The results indicated that the soil predominantly consisted of sand particles(94.27%-99.67%),with the remainder being silt and clay.As plantation age increased,silt and very fine sand contents progressively rose.After 16 years of planting,there was a marked reduction in the mean soil particle size.The initial soil fertility was low and declined from 4 to 10 years of planting before witnessing an improvement.Significant positive correlations were observed for the clay,silt,and very fine sand(mean diameter of 0.000-0.100 mm)with SOC,AK,and p H.In contrast,fine sand and medium sand(mean diameter of 0.100-0.500 mm)showed significant negative correlations with these indicators.Our findings ascertain that the plantation of S.vulgaris requires 10 years to effectively act as a windbreak and contribute to sand fixation,and needs 16 years to improve soil physical and chemical properties.Importantly,these improvements were found to be highly beneficial for vegetation restoration in arid and semi-arid areas.This research can offer valuable insights for the protection and restoration of the vegetation ecosystem in the sandy lands in China.
基金Supported by Special Fund for Forest-scientific Research in the Public Interest of China(201104061)~~
文摘The antibacterial effects of waste liquor of essence oil extraction from Sabina vulgaris Ant on Escherichia coil, Staphylococcus aureus, Salmonella, Bacillus subtilis, Bacillus magaterium and Bacillus cereus in foods were evaluated by paper disk method. The results showed that the waste liquor of essence oil extraction from S. vulgaris had inhibitory effects on E. coil, S. aureus and Salmonella with bet- ter inhibitory effects on E. coil and Salmonella; the bacteriostatic effect of water steam distillation waste liquor was better than that of water extraction waste liquor. The more times the waste liquor was distilled, the higher the active ingredients content was, and the better the bacteriostatic effect was.
文摘duniperus sabina Linnaeus, an evergreen shrub with prostrate life form, can effectively prevent sand moving and is an important tree species for reforestation in semiarid areas of China. It has laterally distributed adventitious roots and a deeply distributed main root system. To detect water movement between the main root system and adventitious roots, we adopted heat pulse sensors using the Heat Ratio Method, a high precision method for measuring low sap flow rates. Two sensors were implanted in each individual in the stem between the main root system and adventitious roots, and another two in lateral stems distal to all the roots. Positive sap flows during nighttime, even under saturated air moisture conditions, were detected only between the main root system and adventitious roots under drought conditions, and the rate of flow increased as drought progressed and decreased or disappeared after rain events. The results demonstrated the existence of water movement from the main root system to adventitious roots, and combined with the high contribution of nighttime sap flow to transpiration （11%-16%） the results indicate that it also involves the process of hydraulic lift, a water movement from moist subsoil to dry surface soils. Integrated water use strategy between the main root system and adventitious roots via the process of hydraulic lift of soil water maximizes water acquisition efficiency from both subsoil water and water from rain pulses on the soil surface; this increases survivability in the water-limited environment of semiarid areas.
基金supported by the National Public Benefit Research Foundation of China (No. 200806036)the National Natural Science Foundation of China (No.30770342 and No.30670319)China Postdoctoral Science Foundation (No.20090460743)
文摘Seasonal variation of foliar δ13C values as well as proline, silicon, MDA and relative water content in Sabina przewalskii Kom. and S. chinensis （Lin.） Ant. were measured. The results show that foliar δ13C values were significantly different at different seasons： lower in winter but higher in summer. δ13C values were positively correlated with air temperature and soil temperature. This demonstrates that foliar δ13C of Sabina is a successful empirical indictor of temperature. Furthermore, foliar δ13C values were positively related to proline and silicon content, and negatively related to relative water content and MDA content. Compared with S. chinensis, S. przewalskii has higher δ13C values, proline and silicon content as well as lower MDA and relative water content. All these results provided strong evidence that it is feasible for δ13C to be regarded as another index to evaluate freezing tolerance of Sabina.
文摘This study presents an analysis of magnetic susceptibility and natural gamma radioactivity as indirect indicators of impurities in Cretaceous limestones of the Sabinas basin, as well as of the possible relation of these physical properties with the changes in the sedimentation environment. Both of these physical properties indicate changes in the degree of impurities and the mineralogical composition of this rock, principally in its organic matter and detritus content. Considering that the sedimentation environment determines the impurities in these rocks, possible environmental conditions at different levels of the Cretaceous were suggested using the magnetic susceptibility, total gamma radiation and potassium values, as well as the uranium and thorium concentration in the limestones. The analyses suggest variations in the depth of water table of the basin, which are mainly related to transgressions and marine regressions.
