In the research, the HPLC technique was applied in order to monitor the hydrolysis and dye-fibre bond-forming during the dyeing process. The results show that using a proper execution of calibration curves of the acti...In the research, the HPLC technique was applied in order to monitor the hydrolysis and dye-fibre bond-forming during the dyeing process. The results show that using a proper execution of calibration curves of the active and hydrolyzed form of the dye and defined equations, HPLC technique enable determining the exact amount of both dye forms anytime during dyeing. Dyeing process was performed in dyeing machine with use of combination of both alkalis—Na2CO3 and NaOH—and with use of one alkali—Na2CO3. It was established that NaOH causes additional hydrolysis of the dye and that the use of Na2CO3 is more appropriate for Novacron Scarlet F-3G dye. The temperature of adsorption has no influence on dye fixation;an amount of fixed dye on fibre is up to 83.0%.展开更多
“Long-Dan”and“Qin-Jiao”are two important TCM herbs since ancient times in China.In the Chinese Pharmacopoeia,the dried roots and rhizomes of four species from the genus Gentiana,e.g.Gentiana manshurica,G.scabra,G....“Long-Dan”and“Qin-Jiao”are two important TCM herbs since ancient times in China.In the Chinese Pharmacopoeia,the dried roots and rhizomes of four species from the genus Gentiana,e.g.Gentiana manshurica,G.scabra,G.triflora and G.rigescens,are recorded under the name of Gentianae Radix et Rhizoma(“Long-Dan”in Chinese),while the other four species from the same genus including G.macrophylla,G.crassicaulis,G.straminea and G.duhurica are recorded and used as the raw materials of Gentianae Macrophyllae Radix(“Qin-Jiao”in Chinese).On the basis of the establishment of a validated HPLC–UV method for quantifying simultaneously,five iridoid glycosides,e.g.loganic acid(1),swertiamarinin(2),gentiopicroside(3),sweroside(4)and 20-(o,m-dihydroxybenzyl)sweroside(5)have been used successfully as chemical markers for the comparison of the species used as“Long-Dan”,“Qin-Jiao”and their adulterants in the present study.The results suggested that four iridoid glycosides 1–4 commonly existed in both“Long-Dan”and“Qin-Jiao”,while 20-(o,m-dihydroxybenzyl)sweroside(5)also existed as one of the major components in“Dian-Long-Dan”species.Moreover,the contents of compounds 1–5 were various in different“LongDan”and“Qin-Jiao”species.Herein,we profiled and compared three“Long-Dan”species,four“Qin-Jiao”species and five adulterants by applying multivariate statistical techniques to their HPLC data sets to establish the differences and/or similarities.展开更多
A simple and efficient HPLC method was developed for quality analysis of flavonoids from Impatiens balsamina L.(IBL)flowers,which were collected from Xingjiang,Anhui,Henan,and Hubei provinces in China.The flavonoids s...A simple and efficient HPLC method was developed for quality analysis of flavonoids from Impatiens balsamina L.(IBL)flowers,which were collected from Xingjiang,Anhui,Henan,and Hubei provinces in China.The flavonoids substances in IBL were determined by HPLC through methyl alcohol ultrasonic extraction.A mixture of展开更多
Radix codonopsis(党参),which is derived fromCodonopsis pilosula, C.pilosula subsp. Modesta andC. Tangshen(ChP,2000),has been used as a remedy fora decrease of appetite, psychoneurosis, fatigue, dyspepsiaetc.or as ...Radix codonopsis(党参),which is derived fromCodonopsis pilosula, C.pilosula subsp. Modesta andC. Tangshen(ChP,2000),has been used as a remedy fora decrease of appetite, psychoneurosis, fatigue, dyspepsiaetc.or as a substitute for Panax ginseng in traditionalChinese medicine. Relating to the constituents of theseherbs, triterpenes, phytosterols, furaldehyde, sesquitesand some phenolic glycosides have been reported, butnone of these compounds seems to be responsible for thebiological activities of this drug. As regards the quality evaluation of Radix Codonopsis, a HPLC analysis of atractylenolide Ⅲ has been described, but this sesquiterpene lactone exists in a very low content and is difficultfor conventional analysis. The determination of polysaccharide also met limitation because of its non-specialization. In this paper, we report the HPLC/MS fingerprintsanalysis of phelolic glycosides from Radix Codonopsis including three species.展开更多
Glycerides are first separated to classes of triglycerides(TGs), diglycerides(DGs) and monoglycerides(MGs) by normal phase HPLC on silica gel column. Individual triglyceride separation is then achieved by non-aqueous ...Glycerides are first separated to classes of triglycerides(TGs), diglycerides(DGs) and monoglycerides(MGs) by normal phase HPLC on silica gel column. Individual triglyceride separation is then achieved by non-aqueous reversed phase(NARP) HPLC on C_(18) column with UV detection at 215nm.展开更多
The suitability of the Folin-Ciocalteu reagent (FCR) and of HPLC for analyzing polyphenols is evaluated. FCR assay is commonly used although its flows, such as overestimating polyphenol content due to interference by ...The suitability of the Folin-Ciocalteu reagent (FCR) and of HPLC for analyzing polyphenols is evaluated. FCR assay is commonly used although its flows, such as overestimating polyphenol content due to interference by oxidizable species, were previously reported. The wide range of oxidizable species present in biological systems seriously compromises this assay’s reliability. Adding small amounts of protein to olive-mill wastewater (OMWW) significantly increased the apparent polyphenol content indicated by the FCR assay. The commonly used “reference” polyphenol as a standard for “total polyphenols” quantification is problematic since each polyphenol responds differently to the FCR. Conversely, HPLC may underestimate polyphenol content. No single HPLC protocol is likely to detect the whole myriad of polyphenols which may be present in a polyphenol-containing system. In analyzing 5 OMWW samples both by FCR assay and HPLC, the polyphenol content indicated by the FCR assay was up to six-fold higher than that determined by HPLC.展开更多
Aim To develop a simple and specific high-performance liquid chromatographic(HPLC) method, suitable for the pharmacokinetic studies in vivo, to determine the concentrations of2-amino-6-cyclopropylamino-9-(2,3-dideoxy-...Aim To develop a simple and specific high-performance liquid chromatographic(HPLC) method, suitable for the pharmacokinetic studies in vivo, to determine the concentrations of2-amino-6-cyclopropylamino-9-(2,3-dideoxy-β-D-glyceropent-2-enofuranosyl)purine (Cyclo-D4G, IMGprodrug) in rat plasma, urine and liver homogenates. Methods Chromatography was performed with C-18Hypersil ODS column and a mobile phase of 7% (v/v) acetonitrile in phosphate buffer, pH 7.40, withUV detection at 283 nm. Results The average extraction recovery of Cyclo-D4G in rat plasma and urinewas 100.1% over its linear range of 0.5 - 80 μg·mL^(-1). The accuracy of the assay was 99.4% .The intra-and inter-day RSDs were less than 9.0% . Conclusion The analytical method was found to beapplicable, reliable and suitable for pharmacokinetic studies.展开更多
The influence of grafting on agronomical and qualitative characteristics of four Sicilian eggplant landraces was investigated. Grafted and ungrafted plants were compared in the open field in the northern coast of Sici...The influence of grafting on agronomical and qualitative characteristics of four Sicilian eggplant landraces was investigated. Grafted and ungrafted plants were compared in the open field in the northern coast of Sicily. Solanum torvum seedlings were used as rootstock. Regardless of genotypes tested, grafting significantly increased total fruit production, marketable production, and number of marketable fruits, but did not affect weight of marketable fruits and waste production. Landrace 2(Sciacca), with black epidermal tissue and pyriform fruit shape, when grafted onto S. torvum not only gave a higher yield performance than ungrafted plants, but also showed a higher phenolic antioxidant content. Landrace 4(Sicilia), with black epidermal tissue and small cylindrical fruits also benefited, when grafted onto S. torvum, from a substantial increase in antioxidant fruit content. As consumers' demand for fruits and vegetables rich in compounds important for human health is steadily increasing, these landrace/rootstock combinations should deserve more attention by plant nurseries involved in grafted seedling production and interested in the valorization and conservation of eggplant biodiversity.展开更多
AimTo characterize the pharmacokinetics of 2 -amino-6-cyclopropylamino-9-(2,3-dideoxy-β-D-glyceropent-2-enofuran osyl) purine (Cyclo-D4G) following intravenous administration and oral administ ration to rats. Methods...AimTo characterize the pharmacokinetics of 2 -amino-6-cyclopropylamino-9-(2,3-dideoxy-β-D-glyceropent-2-enofuran osyl) purine (Cyclo-D4G) following intravenous administration and oral administ ration to rats. MethodsThe concentrations of Cyclo-D4G in rat (Sprague-Dawley male rats) plasma and urine were analyzed by high performance liquid chromatography (HPLC). ResultsFollowing intravenous adm inistration to rats, concentrations of Cyclo-D4G in plasma declined with a term inal phase half-life of 0 78±0 14 h (±s). Total clearance was 0 90±0 21 L·h -1 ·kg -1 . Renal excretion of unchanged Cyclo-D4G accounted for approximately 20% of total clearance. Steady state volume of distr ibution was 0 91±0 07 L·kg -1 . After oral administration to rats, conce ntrations of Cyclo-D4G in plasma declined with a terminal phase half-life of 0 83±0 13 h (±s). Total clearance was 3 81±2 03 L·h -1 ·kg -1 . Renal excretion of unchanged Cyclo-D4G accounted for approximat ely 9% of total clearance. Oral bioavailability of Cyclo-D4G in rat was 26 9%. ConclusionThe favorable pharmacokinetic profiles and lower to xicity provide support for further development of Cyclo-D4G clinical trials.展开更多
Berberine hydrochloride is commonly used to treat bacterial dysentery,gastroenteritis and other diseases.Many manufacturers are available on the market today,while the production process and formulation are quite diff...Berberine hydrochloride is commonly used to treat bacterial dysentery,gastroenteritis and other diseases.Many manufacturers are available on the market today,while the production process and formulation are quite different,which may directly affect the therapeutic effect of the drug.To this end,11 different production producers of berberine hydrochloride tablets were collected according to the pharmacopeia berberine hydrochloride dissolution method(basket method).In addition the dissolution process was carried out in four elution media with different pH,and the difference was similar(f2).Factors were calculated to evaluate in vitro dissolution requirements,and in vitro dissolution of different manufacturers of berberine hydrochloride tablets was determined by high performance liquid chromatography(HPLC).The method was verified by linearity,precision,stability and robustness.Based on the f2 value,there was a significant difference in the dissolution behavior of the formulations of most berberine hydrochloride tablet brands.This research provided the basis for further in-depth research in the later period.Although the drug specifications(0.1 g)were the same,the dissolution curve was different.This phenomenon may be attributed to the fact that the excipients and crystal form of the tablets affected the release and dissolution of the tablets in vitro.展开更多
The present study was designed to isolate and characterize a purified extract from Fusarium solani FG319,termed MFS(Metabolite of Fusarium solani FG319) that showed anti-atherosclerosis activity by inhibiting 3-hydrox...The present study was designed to isolate and characterize a purified extract from Fusarium solani FG319,termed MFS(Metabolite of Fusarium solani FG319) that showed anti-atherosclerosis activity by inhibiting 3-hydroxy-3-methylglutaryl coenzyme A(HMG-Co A) reductase.Response surface methodology(RSM) was employed to achieve an improved yield from the fermentation medium.The inhibiting effect of the isolate,MFS,on HMG-Co A reductase was greater than that of the positive control,lovastatin.The average recovery of MFS and the relative standard deviation(RSD) ranged between 99.75% to 101.18%,and 0.31% to 0.74%,respectively.The RSDs intra-and inter-assay of the three samples ranged from 0.288% to 2.438%,and from 0.934% to 2.383%,respectively.From the RSM,the concentration of inducer,cultivation time,and culture temperatures had significant effects on the MFS production,with the effect of inducer concentration being more pronounced that other factors.In conclusion,the optimal conditions for the MFS production were achieved using RSM and that MFS could be explored as an anti-atherosclerosis agent based on its ability to inhibit HMG-Co A reductase.展开更多
Aims Plants with extrafloral nectaries(EFNs)are common in tropical and subtropical habitats and,despite many other arthropods also forage for EFN,most studies solely focused on the defense mutualisms between EFN plant...Aims Plants with extrafloral nectaries(EFNs)are common in tropical and subtropical habitats and,despite many other arthropods also forage for EFN,most studies solely focused on the defense mutualisms between EFN plants and ants.This study aims at a quantitative assessment of the entire arthropod community that visits EFN trees to compare visitor communities between different tree species to disentangle the mechanisms that may drive EFN visitor community composition.We also test for tree diversity effects on EFN visitors,as it is unknown if local tree species richness relates to the abundance and species richness of arthropods foraging for EFN.Methods We sampled EFN-visiting arthropods in the experimental tree species richness gradient of the BEF-China Experiment,the currently largest forest diversity experiment in the world,and tested if tree species richness affects EFN visitors and if visitor community composition differs between EFN tree species.In a second step,we analyzed the EFN of Ailanthus altissima and Triadica cochinchinensis,the two EFN tree species with highest visitor abundance,for sugars and amino acids(AA)to test if tree species-specific differences in nectar chemistry translate to differing visitor communities.Lastly,we conducted a choice experiment using different artificial nectar solutions to test if nectar quality affects foraging decisions of ants,the most frequent EFN visitors in our study sites.Important Findings EFN trees in young successional forests in subtropical South-East China are visited by a diverse assemblage of arthropods including ants,beetles,flies,and spiders.Albeit ants accounted for about 75%of all individuals,non-ant visitors were by far more species rich.Visitor abundance and species richness declined with increasing tree species richness,suggesting a resource dilution effect,because plots with more tree species had proportionally less EFN tree individuals and thus lower nectar availability.Ailanthus altissima and T.cochinchinensis were visited by different arthropods and their nectar had species-specific AA composition and sugar concentration,indicating that differences in visitors may,at least partly,be explained by differences in nectar chemistry.These findings are supported by the choice experiment,in which artificial nectars containing sugar solutions supplemented with essential AAs attracted more ants than pure sugar solutions or sugar solutions supplemented with non-essential AAs.Our results improve the understanding of the complex ecology of EFN trees,a plant life form that might be crucial for understanding how tree diversity influences patterns of tree growth in young successional tropical and subtropical forests.展开更多
基金The Ministry of Higher Education,Science and Technology financially supported the research under the research program P2-0213,Textiles and Ecology.
文摘In the research, the HPLC technique was applied in order to monitor the hydrolysis and dye-fibre bond-forming during the dyeing process. The results show that using a proper execution of calibration curves of the active and hydrolyzed form of the dye and defined equations, HPLC technique enable determining the exact amount of both dye forms anytime during dyeing. Dyeing process was performed in dyeing machine with use of combination of both alkalis—Na2CO3 and NaOH—and with use of one alkali—Na2CO3. It was established that NaOH causes additional hydrolysis of the dye and that the use of Na2CO3 is more appropriate for Novacron Scarlet F-3G dye. The temperature of adsorption has no influence on dye fixation;an amount of fixed dye on fibre is up to 83.0%.
基金Science and Technology Planning Project of Yunnan Province(2010CD106)the 973 Program of Ministry of Science and Technology of P.R.China(2011CB915503)+1 种基金the State Key Laboratory of Phytochemistry and Plant Resources in West China,KIB,CAS(P2010-ZZ03)The Fourteenth Candidates of the Young Academic Leaders of Yunnan Province(Min XU,2011CI044).
文摘“Long-Dan”and“Qin-Jiao”are two important TCM herbs since ancient times in China.In the Chinese Pharmacopoeia,the dried roots and rhizomes of four species from the genus Gentiana,e.g.Gentiana manshurica,G.scabra,G.triflora and G.rigescens,are recorded under the name of Gentianae Radix et Rhizoma(“Long-Dan”in Chinese),while the other four species from the same genus including G.macrophylla,G.crassicaulis,G.straminea and G.duhurica are recorded and used as the raw materials of Gentianae Macrophyllae Radix(“Qin-Jiao”in Chinese).On the basis of the establishment of a validated HPLC–UV method for quantifying simultaneously,five iridoid glycosides,e.g.loganic acid(1),swertiamarinin(2),gentiopicroside(3),sweroside(4)and 20-(o,m-dihydroxybenzyl)sweroside(5)have been used successfully as chemical markers for the comparison of the species used as“Long-Dan”,“Qin-Jiao”and their adulterants in the present study.The results suggested that four iridoid glycosides 1–4 commonly existed in both“Long-Dan”and“Qin-Jiao”,while 20-(o,m-dihydroxybenzyl)sweroside(5)also existed as one of the major components in“Dian-Long-Dan”species.Moreover,the contents of compounds 1–5 were various in different“LongDan”and“Qin-Jiao”species.Herein,we profiled and compared three“Long-Dan”species,four“Qin-Jiao”species and five adulterants by applying multivariate statistical techniques to their HPLC data sets to establish the differences and/or similarities.
文摘A simple and efficient HPLC method was developed for quality analysis of flavonoids from Impatiens balsamina L.(IBL)flowers,which were collected from Xingjiang,Anhui,Henan,and Hubei provinces in China.The flavonoids substances in IBL were determined by HPLC through methyl alcohol ultrasonic extraction.A mixture of
文摘Radix codonopsis(党参),which is derived fromCodonopsis pilosula, C.pilosula subsp. Modesta andC. Tangshen(ChP,2000),has been used as a remedy fora decrease of appetite, psychoneurosis, fatigue, dyspepsiaetc.or as a substitute for Panax ginseng in traditionalChinese medicine. Relating to the constituents of theseherbs, triterpenes, phytosterols, furaldehyde, sesquitesand some phenolic glycosides have been reported, butnone of these compounds seems to be responsible for thebiological activities of this drug. As regards the quality evaluation of Radix Codonopsis, a HPLC analysis of atractylenolide Ⅲ has been described, but this sesquiterpene lactone exists in a very low content and is difficultfor conventional analysis. The determination of polysaccharide also met limitation because of its non-specialization. In this paper, we report the HPLC/MS fingerprintsanalysis of phelolic glycosides from Radix Codonopsis including three species.
文摘Glycerides are first separated to classes of triglycerides(TGs), diglycerides(DGs) and monoglycerides(MGs) by normal phase HPLC on silica gel column. Individual triglyceride separation is then achieved by non-aqueous reversed phase(NARP) HPLC on C_(18) column with UV detection at 215nm.
文摘The suitability of the Folin-Ciocalteu reagent (FCR) and of HPLC for analyzing polyphenols is evaluated. FCR assay is commonly used although its flows, such as overestimating polyphenol content due to interference by oxidizable species, were previously reported. The wide range of oxidizable species present in biological systems seriously compromises this assay’s reliability. Adding small amounts of protein to olive-mill wastewater (OMWW) significantly increased the apparent polyphenol content indicated by the FCR assay. The commonly used “reference” polyphenol as a standard for “total polyphenols” quantification is problematic since each polyphenol responds differently to the FCR. Conversely, HPLC may underestimate polyphenol content. No single HPLC protocol is likely to detect the whole myriad of polyphenols which may be present in a polyphenol-containing system. In analyzing 5 OMWW samples both by FCR assay and HPLC, the polyphenol content indicated by the FCR assay was up to six-fold higher than that determined by HPLC.
文摘Aim To develop a simple and specific high-performance liquid chromatographic(HPLC) method, suitable for the pharmacokinetic studies in vivo, to determine the concentrations of2-amino-6-cyclopropylamino-9-(2,3-dideoxy-β-D-glyceropent-2-enofuranosyl)purine (Cyclo-D4G, IMGprodrug) in rat plasma, urine and liver homogenates. Methods Chromatography was performed with C-18Hypersil ODS column and a mobile phase of 7% (v/v) acetonitrile in phosphate buffer, pH 7.40, withUV detection at 283 nm. Results The average extraction recovery of Cyclo-D4G in rat plasma and urinewas 100.1% over its linear range of 0.5 - 80 μg·mL^(-1). The accuracy of the assay was 99.4% .The intra-and inter-day RSDs were less than 9.0% . Conclusion The analytical method was found to beapplicable, reliable and suitable for pharmacokinetic studies.
文摘The influence of grafting on agronomical and qualitative characteristics of four Sicilian eggplant landraces was investigated. Grafted and ungrafted plants were compared in the open field in the northern coast of Sicily. Solanum torvum seedlings were used as rootstock. Regardless of genotypes tested, grafting significantly increased total fruit production, marketable production, and number of marketable fruits, but did not affect weight of marketable fruits and waste production. Landrace 2(Sciacca), with black epidermal tissue and pyriform fruit shape, when grafted onto S. torvum not only gave a higher yield performance than ungrafted plants, but also showed a higher phenolic antioxidant content. Landrace 4(Sicilia), with black epidermal tissue and small cylindrical fruits also benefited, when grafted onto S. torvum, from a substantial increase in antioxidant fruit content. As consumers' demand for fruits and vegetables rich in compounds important for human health is steadily increasing, these landrace/rootstock combinations should deserve more attention by plant nurseries involved in grafted seedling production and interested in the valorization and conservation of eggplant biodiversity.
文摘AimTo characterize the pharmacokinetics of 2 -amino-6-cyclopropylamino-9-(2,3-dideoxy-β-D-glyceropent-2-enofuran osyl) purine (Cyclo-D4G) following intravenous administration and oral administ ration to rats. MethodsThe concentrations of Cyclo-D4G in rat (Sprague-Dawley male rats) plasma and urine were analyzed by high performance liquid chromatography (HPLC). ResultsFollowing intravenous adm inistration to rats, concentrations of Cyclo-D4G in plasma declined with a term inal phase half-life of 0 78±0 14 h (±s). Total clearance was 0 90±0 21 L·h -1 ·kg -1 . Renal excretion of unchanged Cyclo-D4G accounted for approximately 20% of total clearance. Steady state volume of distr ibution was 0 91±0 07 L·kg -1 . After oral administration to rats, conce ntrations of Cyclo-D4G in plasma declined with a terminal phase half-life of 0 83±0 13 h (±s). Total clearance was 3 81±2 03 L·h -1 ·kg -1 . Renal excretion of unchanged Cyclo-D4G accounted for approximat ely 9% of total clearance. Oral bioavailability of Cyclo-D4G in rat was 26 9%. ConclusionThe favorable pharmacokinetic profiles and lower to xicity provide support for further development of Cyclo-D4G clinical trials.
基金National Institutes for Food and Drug Control(Grant No.017ZX09101001).
文摘Berberine hydrochloride is commonly used to treat bacterial dysentery,gastroenteritis and other diseases.Many manufacturers are available on the market today,while the production process and formulation are quite different,which may directly affect the therapeutic effect of the drug.To this end,11 different production producers of berberine hydrochloride tablets were collected according to the pharmacopeia berberine hydrochloride dissolution method(basket method).In addition the dissolution process was carried out in four elution media with different pH,and the difference was similar(f2).Factors were calculated to evaluate in vitro dissolution requirements,and in vitro dissolution of different manufacturers of berberine hydrochloride tablets was determined by high performance liquid chromatography(HPLC).The method was verified by linearity,precision,stability and robustness.Based on the f2 value,there was a significant difference in the dissolution behavior of the formulations of most berberine hydrochloride tablet brands.This research provided the basis for further in-depth research in the later period.Although the drug specifications(0.1 g)were the same,the dissolution curve was different.This phenomenon may be attributed to the fact that the excipients and crystal form of the tablets affected the release and dissolution of the tablets in vitro.
基金supported by National High Technology Research and Development Program of China(No.2011AA09070109)Marine Pharmaceutical-food Science Interdisciplinary Project of Shanghai Ocean University
文摘The present study was designed to isolate and characterize a purified extract from Fusarium solani FG319,termed MFS(Metabolite of Fusarium solani FG319) that showed anti-atherosclerosis activity by inhibiting 3-hydroxy-3-methylglutaryl coenzyme A(HMG-Co A) reductase.Response surface methodology(RSM) was employed to achieve an improved yield from the fermentation medium.The inhibiting effect of the isolate,MFS,on HMG-Co A reductase was greater than that of the positive control,lovastatin.The average recovery of MFS and the relative standard deviation(RSD) ranged between 99.75% to 101.18%,and 0.31% to 0.74%,respectively.The RSDs intra-and inter-assay of the three samples ranged from 0.288% to 2.438%,and from 0.934% to 2.383%,respectively.From the RSM,the concentration of inducer,cultivation time,and culture temperatures had significant effects on the MFS production,with the effect of inducer concentration being more pronounced that other factors.In conclusion,the optimal conditions for the MFS production were achieved using RSM and that MFS could be explored as an anti-atherosclerosis agent based on its ability to inhibit HMG-Co A reductase.
基金German Research Foundation(DFG FOR 891/2,KL 1849/6-1)the Sino-German Center for Research Promotion(GZ 785)the German Academic Exchange Service(PROMOS scholarship to J.M.).
文摘Aims Plants with extrafloral nectaries(EFNs)are common in tropical and subtropical habitats and,despite many other arthropods also forage for EFN,most studies solely focused on the defense mutualisms between EFN plants and ants.This study aims at a quantitative assessment of the entire arthropod community that visits EFN trees to compare visitor communities between different tree species to disentangle the mechanisms that may drive EFN visitor community composition.We also test for tree diversity effects on EFN visitors,as it is unknown if local tree species richness relates to the abundance and species richness of arthropods foraging for EFN.Methods We sampled EFN-visiting arthropods in the experimental tree species richness gradient of the BEF-China Experiment,the currently largest forest diversity experiment in the world,and tested if tree species richness affects EFN visitors and if visitor community composition differs between EFN tree species.In a second step,we analyzed the EFN of Ailanthus altissima and Triadica cochinchinensis,the two EFN tree species with highest visitor abundance,for sugars and amino acids(AA)to test if tree species-specific differences in nectar chemistry translate to differing visitor communities.Lastly,we conducted a choice experiment using different artificial nectar solutions to test if nectar quality affects foraging decisions of ants,the most frequent EFN visitors in our study sites.Important Findings EFN trees in young successional forests in subtropical South-East China are visited by a diverse assemblage of arthropods including ants,beetles,flies,and spiders.Albeit ants accounted for about 75%of all individuals,non-ant visitors were by far more species rich.Visitor abundance and species richness declined with increasing tree species richness,suggesting a resource dilution effect,because plots with more tree species had proportionally less EFN tree individuals and thus lower nectar availability.Ailanthus altissima and T.cochinchinensis were visited by different arthropods and their nectar had species-specific AA composition and sugar concentration,indicating that differences in visitors may,at least partly,be explained by differences in nectar chemistry.These findings are supported by the choice experiment,in which artificial nectars containing sugar solutions supplemented with essential AAs attracted more ants than pure sugar solutions or sugar solutions supplemented with non-essential AAs.Our results improve the understanding of the complex ecology of EFN trees,a plant life form that might be crucial for understanding how tree diversity influences patterns of tree growth in young successional tropical and subtropical forests.