采用HPLC-DAD法测定了不同切片厚度在不同烘干温度下唐古特大黄中芦荟大黄素、大黄酸、大黄素、大黄素甲醚、大黄酚的含量,探究切片厚度和烘干温度对唐古特大黄药材质量的影响。色谱柱采用的是Agilent Eclipse plus C 18(4.6×250 m...采用HPLC-DAD法测定了不同切片厚度在不同烘干温度下唐古特大黄中芦荟大黄素、大黄酸、大黄素、大黄素甲醚、大黄酚的含量,探究切片厚度和烘干温度对唐古特大黄药材质量的影响。色谱柱采用的是Agilent Eclipse plus C 18(4.6×250 mm,5μm);流动相A相为色谱级别甲醇,B相为0.1%冰乙酸溶液;柱温25℃;检测波长254 nm。结果表明:75℃烘干,切片厚度以0.4~2 cm或6~7 cm;25、50℃时烘干,切片0.4~3 cm或6~8 cm,药材总蒽醌含量较高,其他厚度含量较低,芦荟大黄素、大黄酸、大黄素、大黄素甲醚、大黄酚的含量也符合上述规律。结论唐古特大黄产地初加工时,75℃烘干,切片厚度以0.4~2 cm或6~7 cm为宜;25和50℃时烘干,切片0.4~3 cm或6~8 cm为宜,从而保证唐古特大黄药材的质量。展开更多
Though aboveground biomass(AGB) has an important contribution to the global carbon cycle,the information about storage and climatic effects of AGB is scare in Three-River Source Region(TRSR)shrub ecosystems. This stud...Though aboveground biomass(AGB) has an important contribution to the global carbon cycle,the information about storage and climatic effects of AGB is scare in Three-River Source Region(TRSR)shrub ecosystems. This study investigated AGB storage and its climatic controls in the TRSR alpine shrub ecosystems using data collected from 23 sites on the Tibetan Plateau from 2011 to 2013. We estimated the AGB storage(both shrub layer biomass and grass layer biomass) in the alpine shrubs as 37.49 Tg, with an average density of 1447.31 g m^(-2). Biomass was primarily accumulated in the shrub layer, which accounted for 92% of AGB, while the grass layer accounted for only 8%. AGB significantly increased with the mean annual temperature(P < 0.05). The effects of the mean annual precipitation on AGB were not significant. These results suggest that temperature,rather than precipitation, has significantly effects on of aboveground vegetation growth in the TRSR alpine shrub ecosystems. The actual and potential increase in AGB density was different due to global warming varies among different regions of the TRSR. We conclude that long-term monitoring of dynamic changes is necessary to improve the accuracy estimations of potential AGB carbon sequestration across the TRSR alpine shrub ecosystems.展开更多
Biodiversity distribution patterns are a basic and long-standing but crucial aspect of ecology research.These patterns form the primary source of data used to develop biodiversity protection practices,especially in mo...Biodiversity distribution patterns are a basic and long-standing but crucial aspect of ecology research.These patterns form the primary source of data used to develop biodiversity protection practices,especially in mountain ecosystems.Shrubs comprise one of the main types of vegetation on the Qinghai–Tibetan Plateau,where they serve vital ecological functions.In this study,we used a community phylogenetic approach to examine the distribution patterns of shrub communities along the longitudinal and latitudinal gradients on the northeastern Qinghai–Tibetan Plateau.We observed significant latitudinal trends in both the phylogenetic diversity(PD)and net relatedness index(NRI)values of shrub communities,such that the former decreased and the latter increased with increasing latitude.However,no significant PD,NRI and nearest taxon index(NTI)distribution patterns were observed along a longitudinal gradient.A further analysis revealed that the combination of temperature-related and precipitation-related climate variables most strongly affected the PD,NRI and NTI values of shrub communities,indicating that the latitudinal patterns in the PD,NRI and NTI of a shrub community may be determined mainly by interactions with these climate factors.展开更多
基金funded by the National Science and Technology Support Project (Grant No.2014BAC05B01)National Program on Basic Work Project of China (Grant No.2015FY11030001)+1 种基金Strategic Priority Research Program of CAS (Grant No.XDA0505030304)National Natural Science Foundation of China (Grant No.40801076)
文摘Though aboveground biomass(AGB) has an important contribution to the global carbon cycle,the information about storage and climatic effects of AGB is scare in Three-River Source Region(TRSR)shrub ecosystems. This study investigated AGB storage and its climatic controls in the TRSR alpine shrub ecosystems using data collected from 23 sites on the Tibetan Plateau from 2011 to 2013. We estimated the AGB storage(both shrub layer biomass and grass layer biomass) in the alpine shrubs as 37.49 Tg, with an average density of 1447.31 g m^(-2). Biomass was primarily accumulated in the shrub layer, which accounted for 92% of AGB, while the grass layer accounted for only 8%. AGB significantly increased with the mean annual temperature(P < 0.05). The effects of the mean annual precipitation on AGB were not significant. These results suggest that temperature,rather than precipitation, has significantly effects on of aboveground vegetation growth in the TRSR alpine shrub ecosystems. The actual and potential increase in AGB density was different due to global warming varies among different regions of the TRSR. We conclude that long-term monitoring of dynamic changes is necessary to improve the accuracy estimations of potential AGB carbon sequestration across the TRSR alpine shrub ecosystems.
基金funded jointly by the Natural Science Foundation of Qinghai Province(2019-ZJ-910)the International Communication and Cooperation Project of Qinghai Province(2019-HZ-807)+1 种基金the National Program on Basic Work Project of China(2015FY11030001)the Qinghai Province High-level Innovative Talents Program
文摘Biodiversity distribution patterns are a basic and long-standing but crucial aspect of ecology research.These patterns form the primary source of data used to develop biodiversity protection practices,especially in mountain ecosystems.Shrubs comprise one of the main types of vegetation on the Qinghai–Tibetan Plateau,where they serve vital ecological functions.In this study,we used a community phylogenetic approach to examine the distribution patterns of shrub communities along the longitudinal and latitudinal gradients on the northeastern Qinghai–Tibetan Plateau.We observed significant latitudinal trends in both the phylogenetic diversity(PD)and net relatedness index(NRI)values of shrub communities,such that the former decreased and the latter increased with increasing latitude.However,no significant PD,NRI and nearest taxon index(NTI)distribution patterns were observed along a longitudinal gradient.A further analysis revealed that the combination of temperature-related and precipitation-related climate variables most strongly affected the PD,NRI and NTI values of shrub communities,indicating that the latitudinal patterns in the PD,NRI and NTI of a shrub community may be determined mainly by interactions with these climate factors.
