Biodiversity is declining at an unprecedented rate.Many grassland species have been lost and are now of conservation concern.Identifying efficient biodiversity indicators is a key pillar of the global conservation str...Biodiversity is declining at an unprecedented rate.Many grassland species have been lost and are now of conservation concern.Identifying efficient biodiversity indicators is a key pillar of the global conservation strategy.Mongolian Lark(Melanocorypha mongolica) is a charismatic bird species abound in Mongolian steppes,and recent studies demonstrated that this species share similar habitat requirements an d likely co-occur with other grassland birds.We tested the hypothesis that Mongolian Lark would make a suitable indicator for different aspects of avian biodiversity.We made a large-scale bird survey in Inner Mongolia,and classified point counts into three groups based on different taxonomic,functional,and phylogenetic biodiversity measures.We identified species indicators of each group using the indicator value(IndVal) analysis,and examined the bird compositional difference among groups.Linear models were used for studying the patterns of occurrence of Mongolian Lark in relation to various biodiversity measures.Mon golian Lark showed the highest indicator value in comparison with other potential species indicators.Bird species richness is significantly higher at sites with Mongolian Lark,an d its occurrence was negatively correlated with species abundance,functional richness,Rao’s quadratic entropy and phylogenetic diversity.Mongolian Lark is therefore a suitable indicator species for avian biodiversity in Mongolian steppes.It is highly distinctive in flight and usually seen singly.The widespread distribution and charismatic appearance make it easy to monitor and adequate for citizen science,and may provide useful information on the paradigm of surrogacy in conservation ecology.展开更多
A new species,Neottia wuyishanensis(Neottieae,Orchidaceae),is described and illustrated from Wuyishan,Fujian,eastern China,based on morphological characters and molecular data.Molecular phylogenetics indicate that N.w...A new species,Neottia wuyishanensis(Neottieae,Orchidaceae),is described and illustrated from Wuyishan,Fujian,eastern China,based on morphological characters and molecular data.Molecular phylogenetics indicate that N.wuyishanensis is nested within the clade formed by Neottia fugongensis and Neottia nujiangensis.Morphologically,N.wuyishanensis is similar to N.fugongensis and N.pseudonipponica,but differs from them by having indistinct auricles at the base,and in the shape and size of lobelets.展开更多
于2023年,对采自武夷山国家公园的松墨天牛(Monochamus alternatus)幼虫僵虫的寄生真菌进行分离培养,获得1株虫生真菌(BbWYZ-06),利用形态学观察和系统发育分析对该菌株进行鉴定,并测定该菌株的生物学特性以及对松墨天牛幼虫的致病性。...于2023年,对采自武夷山国家公园的松墨天牛(Monochamus alternatus)幼虫僵虫的寄生真菌进行分离培养,获得1株虫生真菌(BbWYZ-06),利用形态学观察和系统发育分析对该菌株进行鉴定,并测定该菌株的生物学特性以及对松墨天牛幼虫的致病性。结果表明,菌株BbWYZ-06的培养特征与白僵菌属球孢白僵菌较为一致,基于核糖体内转录间隔区(internal transcribed spacers, ITS)和RNA聚合酶Ⅱ的第2亚基(the second largest subunit of the nuclear RNA polymerase enzymeⅡ,RPB2)序列构建系统发育树,该菌株与球孢白僵菌(Beauveria bassiana)聚在同一分支,因此将菌株BbWYZ-06鉴定为球孢白僵菌。在25℃下,菌株BbWYZ-06在PDA培养基上的菌落生长速率为(2.54±0.25) mm·d^(-1),培养第15天时的产孢量为(2.11±0.23)×10^(8)个·cm^(-2)。菌株BbWYZ-06对松墨天牛幼虫具有较强的致病性,孢子悬浮液为1.0×10^(7)个·mL^(-1)时,松墨天牛幼虫第7天累计死亡率达93%,LT50值为3.95 d,在松墨天牛生物防治中具有良好的应用潜力。展开更多
Green hydrogen is urgently required for sustainable development of human beings and rational construction of heterostructures holds great promising for photocatalytic hydrogen generation.Herein,2D/2D WSe_(2)/ZnIn_(2)S...Green hydrogen is urgently required for sustainable development of human beings and rational construction of heterostructures holds great promising for photocatalytic hydrogen generation.Herein,2D/2D WSe_(2)/ZnIn_(2)S_(4) heterostructures with strong hetero-interface interaction and abundant contact were constructed via an impregnation-annealing strategy.Efficient charge transfer from ZnIn_(2)S_(4) to WSe_(2)was evidenced by transient absorption spectroscopy in crafted heterostructures owing to the tight and2D face-to-face contact.As a result,the prepared WSe_(2)/ZnIn_(2)S_(4) heterostructures exhibited boosted photocatalytic performance and a highest hydrogen evolution rate of 3.377 mmol/(g h)was achieved with an apparent quantum yield of 45.7%at 420 nm.The work not only provides new strategies to achieve efficient 2D/2D heterostructures but also paves the way for the development of green hydrogen in the future.展开更多
BACKGROUND Although chronic erosive gastritis(CEG)is common,its clinical characteristics have not been fully elucidated.The lack of consensus regarding its treatment has resulted in varied treatment regimens.AIM To ex...BACKGROUND Although chronic erosive gastritis(CEG)is common,its clinical characteristics have not been fully elucidated.The lack of consensus regarding its treatment has resulted in varied treatment regimens.AIM To explore the clinical characteristics,treatment patterns,and short-term outcomes in CEG patients in China.METHODS We recruited patients with chronic non-atrophic or mild-to-moderate atrophic gastritis with erosion based on endoscopy and pathology.Patients and treating physicians completed a questionnaire regarding history,endoscopic findings,and treatment plans as well as a follow-up questionnaire to investigate changes in symptoms after 4 wk of treatment.RESULTS Three thousand five hundred sixty-three patients from 42 centers across 24 cities in China were included.Epigastric pain(68.0%),abdominal distension(62.6%),and postprandial fullness(47.5%)were the most common presenting symptoms.Gastritis was classified as chronic non-atrophic in 69.9%of patients.Among those with erosive lesions,72.1%of patients had lesions in the antrum,51.0%had multiple lesions,and 67.3%had superficial flat lesions.In patients with epigastric pain,the combination of a mucosal protective agent(MPA)and proton pump inhibitor was more effective.For those with postprandial fullness,acid regurgitation,early satiety,or nausea,a MPA appeared more promising.CONCLUSION CEG is a multifactorial disease which is common in Asian patients and has non-specific symptoms.Gastroscopy may play a major role in its detection and diagnosis.Treatment should be individualized based on symptom profile.展开更多
在对龙岩市东肖桫椤谷石松类和蕨类植物资源进行野外调查和资料整理的基础上,依据《Flora of China》进行分类鉴定,统计分析该区石松类和蕨类植物资源。结果表明:①该区共有石松类和蕨类植物22科50属95种,优势科为凤尾蕨科(Pteridaceae...在对龙岩市东肖桫椤谷石松类和蕨类植物资源进行野外调查和资料整理的基础上,依据《Flora of China》进行分类鉴定,统计分析该区石松类和蕨类植物资源。结果表明:①该区共有石松类和蕨类植物22科50属95种,优势科为凤尾蕨科(Pteridaceae)、水龙骨科(Polypodiaceae),优势属为凤尾蕨属(Pteris),单种科和寡种科占总科数的68.18%,单种属和寡种属占总属数的94.00%,科属内结构简单,分化程度不高。②陆生石松类和蕨类植物占总种数的53.68%,为主要的生态类型。③观赏石松类和蕨类植物占总种数的68.42%,可为石松类和蕨类植物的园林应用提供大量的资源。展开更多
Pepper(Capsicum annuum L.)is frequently challenged by various pathogens,among which Phytophthora capsici is the most devastating to pepper production.Red light signal acts as a positive induction of plant resistance a...Pepper(Capsicum annuum L.)is frequently challenged by various pathogens,among which Phytophthora capsici is the most devastating to pepper production.Red light signal acts as a positive induction of plant resistance against multiple pathogens.However,little is known about how the red light signal affects pepper resistance to P.capsici infection(PCI).Here,we report that red light regulates salicylic acid(SA)accumulation by activating elongated hypocotyl5(CaHY5),a basic leucine zipper(bZIP)transcription factor,thereby decreasing pepper susceptibility to PCI.Exogenous SA treatment reduced pepper susceptibility to PCI,while silencing of CaPHYB(a red light photoreceptor)increased its susceptibility.PCI significantly induced CaHY5 expression,and silencing of CaHY5 reduced SA accumulation,accompanied by decreases in the expression levels of phenylalanine ammonia-lyase 3(CaPAL3),CaPAL7,pathogenesis-related 1(CaPR1),and CaPR1L,which finally resulted in higher susceptibility of pepper to PCI.Moreover,CaHY5 was found to activate the expression of CaPAL3 and CaPAL7,which are essential for SA biosynthesis,by directly binding to their promoters.Further analysis revealed that exogenous SA treatment could restore the resistance of CaHY5-silenced pepper plants to PCI.Collectively,this study reveals a critical mechanism through which red light induces SA accumulation by regulating CaHY5-mediated CaPAL3 and CaPAL7 expression,leading to enhanced resistance to PCI.Moreover,red light-induced CaHY5 regulates pepper resistance to PCI,which may have implications for PCI control in protected vegetable production.展开更多
The interaction between axially adjacent defects is more significant than that between circumferentially aligned defects.However,the existing failure pressure assessment methods cannot accurately predict the failure p...The interaction between axially adjacent defects is more significant than that between circumferentially aligned defects.However,the existing failure pressure assessment methods cannot accurately predict the failure pressure of axial adjacent defects.In the paper,the finite element model is adopted to analyze the influence of defect size,distribution mode and spacing between adjacent defects on failure pressure.A new failure pressure evaluation method is proposed by establishing the effective depth calculation model of corrosion colony with different distribution model.The burst test of X52 pipeline is carried out to verify the applicability of the method.It shows that the results of new method are consistent with the test results of pipeline with various defects and steel grades.展开更多
This study investigated the impacts of increasing model resolutions and shortening forecast lead times on the quantitative precipitation forecast(QPF)for heavy-rainfall events over south China during the rainy seasons...This study investigated the impacts of increasing model resolutions and shortening forecast lead times on the quantitative precipitation forecast(QPF)for heavy-rainfall events over south China during the rainy seasons in 2013-2020.The control experiment,where the analysis-forecast cycles run with model resolutions of about 3 km,was compared to a lower-resolution experiment with model resolutions of about 9 km,and a longer-term experiment activated 12 hours earlier.Rainfall forecasting in the presummer rainy season was significantly improved by improving model resolutions,with more improvements in cases with stronger synoptic-scale forcings.This is partially attributed to the improved initial conditions(ICs)and subsequent forecasts for low-level jets(LLJs).Forecasts of heavy rainfall induced by landfalling tropical cyclones(TCs)benefited from increasing model resolutions in the first 6 hours.Forecast improvements in rainfall due to shortening forecast lead times were more significant at earlier(1-6 h)and later(7-12 h)lead times for cases with stronger and weaker synoptic-scale forcings,respectively,due to the area-and case-dependent improvements in ICs for nonprecipitation variables.Specifically,significant improvements mainly presented over the northern South China Sea for low-level onshore wind of weak-forcing cases but over south China for LLJs of strong-forcing cases during the presummer rainy season,and over south China for all the nonprecipitation variables above the surface during the TC season.However,some disadvantages of higher-resolution and shorter-term forecasts in QPFs highlight the importance of developing ensemble forecasting with proper IC perturbations,which include the complementary advantages of lower-resolution and longer-term forecasts.展开更多
考察了LX-36型大孔吸附树脂纯化黄芪茎总黄酮的工艺条件及其体外抗氧化性。以总黄酮的吸附率及解吸率为参考指标,采用单因素和正交试验法对黄芪茎总黄酮的纯化工艺进行优化;通过黄芪茎总黄酮样品液对DPPH·(二苯代苦味酰基自由基)、...考察了LX-36型大孔吸附树脂纯化黄芪茎总黄酮的工艺条件及其体外抗氧化性。以总黄酮的吸附率及解吸率为参考指标,采用单因素和正交试验法对黄芪茎总黄酮的纯化工艺进行优化;通过黄芪茎总黄酮样品液对DPPH·(二苯代苦味酰基自由基)、·OH(羟基自由基)的清除率来考察其体外抗氧化活性。结果表明,黄芪茎总黄酮的最佳纯化工艺条件为:样品液的生药质量浓度为0.06 g/m L,pH为3.5,样品液体积/树脂质量为15 m L/g。振荡吸附时间为3.0 h,洗脱剂为80%(体积分数)的乙醇溶液,振荡解吸时间为1 h,解吸液体积/树脂质量为25 m L/g,在此条件下,黄芪茎浸膏中总黄酮的含量由7.16%提高到13.55%;黄芪茎总黄酮样品液对DPPH·、·OH具有较强的清除能力,而且其清除活性随黄芪茎总黄酮样品液质量浓度的增加而增强。展开更多
基金the National Natural Science Foundation of China(No.32201304)the Fundamental Research Funds for the Central Universities(No.2412022QD026).
文摘Biodiversity is declining at an unprecedented rate.Many grassland species have been lost and are now of conservation concern.Identifying efficient biodiversity indicators is a key pillar of the global conservation strategy.Mongolian Lark(Melanocorypha mongolica) is a charismatic bird species abound in Mongolian steppes,and recent studies demonstrated that this species share similar habitat requirements an d likely co-occur with other grassland birds.We tested the hypothesis that Mongolian Lark would make a suitable indicator for different aspects of avian biodiversity.We made a large-scale bird survey in Inner Mongolia,and classified point counts into three groups based on different taxonomic,functional,and phylogenetic biodiversity measures.We identified species indicators of each group using the indicator value(IndVal) analysis,and examined the bird compositional difference among groups.Linear models were used for studying the patterns of occurrence of Mongolian Lark in relation to various biodiversity measures.Mon golian Lark showed the highest indicator value in comparison with other potential species indicators.Bird species richness is significantly higher at sites with Mongolian Lark,an d its occurrence was negatively correlated with species abundance,functional richness,Rao’s quadratic entropy and phylogenetic diversity.Mongolian Lark is therefore a suitable indicator species for avian biodiversity in Mongolian steppes.It is highly distinctive in flight and usually seen singly.The widespread distribution and charismatic appearance make it easy to monitor and adequate for citizen science,and may provide useful information on the paradigm of surrogacy in conservation ecology.
基金financially supported by Project of Orchid Biodiversity Survey of ChinaNational Forestry and Grassland Administration(Grant No.2020-07)+1 种基金the Sub-projectⅥof National Program on Key Basic Research Project(973 Program)(Grant No.2015FY110200)the National Special Fund for Chinese Medicine Resources Research in the Public Interest of China(Grant No.2019-39)。
文摘A new species,Neottia wuyishanensis(Neottieae,Orchidaceae),is described and illustrated from Wuyishan,Fujian,eastern China,based on morphological characters and molecular data.Molecular phylogenetics indicate that N.wuyishanensis is nested within the clade formed by Neottia fugongensis and Neottia nujiangensis.Morphologically,N.wuyishanensis is similar to N.fugongensis and N.pseudonipponica,but differs from them by having indistinct auricles at the base,and in the shape and size of lobelets.
文摘于2023年,对采自武夷山国家公园的松墨天牛(Monochamus alternatus)幼虫僵虫的寄生真菌进行分离培养,获得1株虫生真菌(BbWYZ-06),利用形态学观察和系统发育分析对该菌株进行鉴定,并测定该菌株的生物学特性以及对松墨天牛幼虫的致病性。结果表明,菌株BbWYZ-06的培养特征与白僵菌属球孢白僵菌较为一致,基于核糖体内转录间隔区(internal transcribed spacers, ITS)和RNA聚合酶Ⅱ的第2亚基(the second largest subunit of the nuclear RNA polymerase enzymeⅡ,RPB2)序列构建系统发育树,该菌株与球孢白僵菌(Beauveria bassiana)聚在同一分支,因此将菌株BbWYZ-06鉴定为球孢白僵菌。在25℃下,菌株BbWYZ-06在PDA培养基上的菌落生长速率为(2.54±0.25) mm·d^(-1),培养第15天时的产孢量为(2.11±0.23)×10^(8)个·cm^(-2)。菌株BbWYZ-06对松墨天牛幼虫具有较强的致病性,孢子悬浮液为1.0×10^(7)个·mL^(-1)时,松墨天牛幼虫第7天累计死亡率达93%,LT50值为3.95 d,在松墨天牛生物防治中具有良好的应用潜力。
基金financially supported by the National Natural Science Foundation of China (No.52106259)the Fundamental Research Funds for the Central Universities (2024MS013)Key Research and Development Program of Shaanxi (Program No.2022LL-JB-08)。
文摘Green hydrogen is urgently required for sustainable development of human beings and rational construction of heterostructures holds great promising for photocatalytic hydrogen generation.Herein,2D/2D WSe_(2)/ZnIn_(2)S_(4) heterostructures with strong hetero-interface interaction and abundant contact were constructed via an impregnation-annealing strategy.Efficient charge transfer from ZnIn_(2)S_(4) to WSe_(2)was evidenced by transient absorption spectroscopy in crafted heterostructures owing to the tight and2D face-to-face contact.As a result,the prepared WSe_(2)/ZnIn_(2)S_(4) heterostructures exhibited boosted photocatalytic performance and a highest hydrogen evolution rate of 3.377 mmol/(g h)was achieved with an apparent quantum yield of 45.7%at 420 nm.The work not only provides new strategies to achieve efficient 2D/2D heterostructures but also paves the way for the development of green hydrogen in the future.
基金the National Key Clinical Specialty Construction Project,No.ZK108000CAMS Innovation Fund for Medical Sciences,No.2021-I2M-C&T-A-001 and No.2022-I2M-C&T-B-012.
文摘BACKGROUND Although chronic erosive gastritis(CEG)is common,its clinical characteristics have not been fully elucidated.The lack of consensus regarding its treatment has resulted in varied treatment regimens.AIM To explore the clinical characteristics,treatment patterns,and short-term outcomes in CEG patients in China.METHODS We recruited patients with chronic non-atrophic or mild-to-moderate atrophic gastritis with erosion based on endoscopy and pathology.Patients and treating physicians completed a questionnaire regarding history,endoscopic findings,and treatment plans as well as a follow-up questionnaire to investigate changes in symptoms after 4 wk of treatment.RESULTS Three thousand five hundred sixty-three patients from 42 centers across 24 cities in China were included.Epigastric pain(68.0%),abdominal distension(62.6%),and postprandial fullness(47.5%)were the most common presenting symptoms.Gastritis was classified as chronic non-atrophic in 69.9%of patients.Among those with erosive lesions,72.1%of patients had lesions in the antrum,51.0%had multiple lesions,and 67.3%had superficial flat lesions.In patients with epigastric pain,the combination of a mucosal protective agent(MPA)and proton pump inhibitor was more effective.For those with postprandial fullness,acid regurgitation,early satiety,or nausea,a MPA appeared more promising.CONCLUSION CEG is a multifactorial disease which is common in Asian patients and has non-specific symptoms.Gastroscopy may play a major role in its detection and diagnosis.Treatment should be individualized based on symptom profile.
文摘在对龙岩市东肖桫椤谷石松类和蕨类植物资源进行野外调查和资料整理的基础上,依据《Flora of China》进行分类鉴定,统计分析该区石松类和蕨类植物资源。结果表明:①该区共有石松类和蕨类植物22科50属95种,优势科为凤尾蕨科(Pteridaceae)、水龙骨科(Polypodiaceae),优势属为凤尾蕨属(Pteris),单种科和寡种科占总科数的68.18%,单种属和寡种属占总属数的94.00%,科属内结构简单,分化程度不高。②陆生石松类和蕨类植物占总种数的53.68%,为主要的生态类型。③观赏石松类和蕨类植物占总种数的68.42%,可为石松类和蕨类植物的园林应用提供大量的资源。
基金supported by grants from the National Natural Science Foundation of China(32002030)Major Discipline Academic and Technical Leaders Training Program of Jiangxi Province,China-Young Talents Project(20204BCJL23044)+3 种基金the China Postdoctoral Science Foundation(2020 M682732)the Yan’an University Doctoral Research Initiation Project(YAU202313800)China Agriculture Research System of MOF and MARA(CARS-24-B-01)the earmarked fund for Jiangxi Agriculture Research System(JXARS-06).
文摘Pepper(Capsicum annuum L.)is frequently challenged by various pathogens,among which Phytophthora capsici is the most devastating to pepper production.Red light signal acts as a positive induction of plant resistance against multiple pathogens.However,little is known about how the red light signal affects pepper resistance to P.capsici infection(PCI).Here,we report that red light regulates salicylic acid(SA)accumulation by activating elongated hypocotyl5(CaHY5),a basic leucine zipper(bZIP)transcription factor,thereby decreasing pepper susceptibility to PCI.Exogenous SA treatment reduced pepper susceptibility to PCI,while silencing of CaPHYB(a red light photoreceptor)increased its susceptibility.PCI significantly induced CaHY5 expression,and silencing of CaHY5 reduced SA accumulation,accompanied by decreases in the expression levels of phenylalanine ammonia-lyase 3(CaPAL3),CaPAL7,pathogenesis-related 1(CaPR1),and CaPR1L,which finally resulted in higher susceptibility of pepper to PCI.Moreover,CaHY5 was found to activate the expression of CaPAL3 and CaPAL7,which are essential for SA biosynthesis,by directly binding to their promoters.Further analysis revealed that exogenous SA treatment could restore the resistance of CaHY5-silenced pepper plants to PCI.Collectively,this study reveals a critical mechanism through which red light induces SA accumulation by regulating CaHY5-mediated CaPAL3 and CaPAL7 expression,leading to enhanced resistance to PCI.Moreover,red light-induced CaHY5 regulates pepper resistance to PCI,which may have implications for PCI control in protected vegetable production.
基金supported by the Key Scientific Research Projects of Colleges and Universities in Henan Province(Grant No.23A560013)the National Key R&D Program of the“14th Five-Year Plan”(Grant No.2022YFC3801001)+1 种基金Henan Provincial Youth Science Foundation(Grant No.232300421328)the Leading Talents in Zhongyuan Technology Innovation(Grant No.234200510014).
文摘The interaction between axially adjacent defects is more significant than that between circumferentially aligned defects.However,the existing failure pressure assessment methods cannot accurately predict the failure pressure of axial adjacent defects.In the paper,the finite element model is adopted to analyze the influence of defect size,distribution mode and spacing between adjacent defects on failure pressure.A new failure pressure evaluation method is proposed by establishing the effective depth calculation model of corrosion colony with different distribution model.The burst test of X52 pipeline is carried out to verify the applicability of the method.It shows that the results of new method are consistent with the test results of pipeline with various defects and steel grades.
基金National Key Research and Development Program of China(2017YFC1501603)National Natural Science Foundation of China(41975136,42075014)+2 种基金Startup Foundation for Introducing Talent of NUIST(2023r121)Guangdong Basic and Applied Basic Research Foundation(2019A1515011118)Guangzhou Municipal Science and Technology Planning Project of China(202103000030)。
文摘This study investigated the impacts of increasing model resolutions and shortening forecast lead times on the quantitative precipitation forecast(QPF)for heavy-rainfall events over south China during the rainy seasons in 2013-2020.The control experiment,where the analysis-forecast cycles run with model resolutions of about 3 km,was compared to a lower-resolution experiment with model resolutions of about 9 km,and a longer-term experiment activated 12 hours earlier.Rainfall forecasting in the presummer rainy season was significantly improved by improving model resolutions,with more improvements in cases with stronger synoptic-scale forcings.This is partially attributed to the improved initial conditions(ICs)and subsequent forecasts for low-level jets(LLJs).Forecasts of heavy rainfall induced by landfalling tropical cyclones(TCs)benefited from increasing model resolutions in the first 6 hours.Forecast improvements in rainfall due to shortening forecast lead times were more significant at earlier(1-6 h)and later(7-12 h)lead times for cases with stronger and weaker synoptic-scale forcings,respectively,due to the area-and case-dependent improvements in ICs for nonprecipitation variables.Specifically,significant improvements mainly presented over the northern South China Sea for low-level onshore wind of weak-forcing cases but over south China for LLJs of strong-forcing cases during the presummer rainy season,and over south China for all the nonprecipitation variables above the surface during the TC season.However,some disadvantages of higher-resolution and shorter-term forecasts in QPFs highlight the importance of developing ensemble forecasting with proper IC perturbations,which include the complementary advantages of lower-resolution and longer-term forecasts.
文摘考察了LX-36型大孔吸附树脂纯化黄芪茎总黄酮的工艺条件及其体外抗氧化性。以总黄酮的吸附率及解吸率为参考指标,采用单因素和正交试验法对黄芪茎总黄酮的纯化工艺进行优化;通过黄芪茎总黄酮样品液对DPPH·(二苯代苦味酰基自由基)、·OH(羟基自由基)的清除率来考察其体外抗氧化活性。结果表明,黄芪茎总黄酮的最佳纯化工艺条件为:样品液的生药质量浓度为0.06 g/m L,pH为3.5,样品液体积/树脂质量为15 m L/g。振荡吸附时间为3.0 h,洗脱剂为80%(体积分数)的乙醇溶液,振荡解吸时间为1 h,解吸液体积/树脂质量为25 m L/g,在此条件下,黄芪茎浸膏中总黄酮的含量由7.16%提高到13.55%;黄芪茎总黄酮样品液对DPPH·、·OH具有较强的清除能力,而且其清除活性随黄芪茎总黄酮样品液质量浓度的增加而增强。
