Aims Recent studies have shown that alpine meadows on the Qinghai-Tibetan plateau act as significant CO_(2)sinks.On the plateau,alpine shrub meadow is one of typical grassland ecosystems.The major alpine shrub on the ...Aims Recent studies have shown that alpine meadows on the Qinghai-Tibetan plateau act as significant CO_(2)sinks.On the plateau,alpine shrub meadow is one of typical grassland ecosystems.The major alpine shrub on the plateau is Potentilla fruticosa L.(Rosaceae),which is distributed widely from 3200 to 4000 m.Shrub species play an important role on carbon sequestration in grassland ecosystems.In addition,alpine shrubs are sensitive to climate change such as global warming.Considering global warming,the biomass and productivity of P.fruticosa will increase on Qinghai-Tibetan Plateau.Thus,understanding the carbon dynamics in alpine shrub meadow and the role of shrubs around the upper distribution limit at present is essential to predict the change in carbon sequestration on the plateau.However,the role of shrubs on the carbon dynamics in alpine shrub meadow remains unclear.The objectives of the present study were to evaluate the magnitude of CO_(2)exchange of P.fruticosa shrub patches around the upper distribution limit and to elucidate the role of P.fruticosa on ecosystem CO_(2)fluxes in an alpine meadow.Methods We used the static acrylic chamber technique to measure and estimate the net ecosystem productivity(NEP),ecosystem respiration(Re),and gross primary productivity(GPP)of P.fruticosa shrub patches at three elevations around the species’upper distribution limit.Ecosystem CO_(2)fluxes and environmental factors were measured from 17 to 20 July 2008 at 3400,3600,and 3800 m a.s.l.We examined the maximum GPP at infinite light(GPPmax)and maximum Re(Remax)during the experimental time at each elevation in relation to aboveground biomass and environmental factors,including air and soil temperature,and soil water content.Important Findings Patches of P.fruticosa around the species’upper distribution limit absorbed CO_(2),at least during the daytime.Maximum NEP at infinite light(NEPmax)and GPPmax of shrub patches in the alpine meadow varied among the three elevations,with the highest values at 3400 m and the lowest at 3800 m.GPPmax was positively correlated with the green biomass of P.fruticosa more strongly than with total green biomass,suggesting that P.fruticosa is the major contributor to CO_(2)uptake in the alpine shrub meadow.Air temperature influenced the potential GPPat the shrub-patch scale.Remax was correlated with aboveground biomass and Remax normalized by aboveground biomass was influenced by soil water content.Potentilla fruticosa height(biomass)and frequency increased clearly as elevation decreased,which promotes the large-scale spatial variation of carbon uptake and the strength of the carbon sink at lower elevations.展开更多
Background Microbial communities in different plant compartments are relatively independent entities.However,the influence of environmental factors on the microbial community in different compartments of periglacial p...Background Microbial communities in different plant compartments are relatively independent entities.However,the influence of environmental factors on the microbial community in different compartments of periglacial plants remains unclear.In this study,we quantified the bacterial communities in the rhizosphere soil,as well as root and leaf endosphere compartments of a periglacial plant,Potentilla fruticosa var.albicans,using high-throughput DNA sequencing.Moreover,we evaluated the impacts of habitat types(glacier terminus zone,moraine ridge,and alpine meadow)on the bacterial community in different plant compartments of Potentilla fruticosa var.albicans.Results Our results showed that habitat type had a significant effect on the alpha diversity(Chao1 richness)of endophytic bacteria,but not on the rhizospheric bacteria.The community composition of rhizospheric and endophytic bacteria was significantly different across the three habitats,and habitat type had a greater effect on the endophytic bacteria than on rhizospheric bacteria.The contribution of rhizosphere soil to the root and leaf endophytes decreased with the transformation of habitats from glacier terminus zone to alpine meadow.In contrast,host selection pressure sequentially increased from the glacier terminus zone to the moraine ridge to the alpine meadow.Furthermore,we found that the bacterial co-occurrence network in the alpine meadow was more modular but had lower complexity and connectedness than that in the glacier terminus zone.The bacterial community was governed primarily by stochastic processes regardless of habitat type.Conclusion This study reveals that the diversity and composition of endophytic bacteria associated with Potentilla fruticosa var.albicans are more affected by habitat types than that of rhizospheric bacteria.Our study also demonstrates that the assembly patterns and co-occurrence patterns of bacterial communities associated with Potentilla fruticosa var.albicans vary by habitat type.These results advance the current understanding of community assembly and ecological interactions of microbial communities associated with periglacial plants.展开更多
[Objectives]To study the effects of Fruticosa potentilla L.on the expression of key enzymes and hormones related to glucose and lipid metabolism in T2DM rats.[Methods]The ethyl acetate fraction of 95%methanol extract ...[Objectives]To study the effects of Fruticosa potentilla L.on the expression of key enzymes and hormones related to glucose and lipid metabolism in T2DM rats.[Methods]The ethyl acetate fraction of 95%methanol extract of F.potentilla(MEE)was administered orally to the T2DM rats,and the level of glucose and expression of insulin,resistin,leptin,glucokinase(GK)and glucose-6-phosphatase(G-6-Pase)in the rats were measured and detected.[Results]In the T2DM rats administered with MEE,the postprandial blood glucose level decreased,the expression levels of resistin,leptin and G-6-Pase were down-regulated,and the expression levels of insulin and GK were up-regulated(P<0.05,P<0.01).[Conclusions]F.potentilla can reduce effectively postprandial blood glucose level,regulate the expression of a variety of enzymes and hormones related to glucose and lipid metabolism and recover partially the insulin level in T2DM rats to achieve resistance to T2DM.展开更多
The techniques of cutting propagation of Potentilla fruticosa was studied.The tender stem cuttings and the woody stem cuttings were treated by different concentrations of BBA(0 mg·kg-1,10 mg·kg-1,50 mg·...The techniques of cutting propagation of Potentilla fruticosa was studied.The tender stem cuttings and the woody stem cuttings were treated by different concentrations of BBA(0 mg·kg-1,10 mg·kg-1,50 mg·kg-1,100 mg·kg-1,200 mg·kg-1,500 mg·kg-1).The results indicated that the rooting percentage of tender stem cuttings at the concentration of 10 mg ·kg-1BBA was the highest(88.3%),and that of woody stem cuttings treated by the concentration of 50 mg·kg-1BBA was the highest(66.67%).It also indicated that the rooting percentages of the tender stem cuttings were better than those of the woody stem cuttings with same treatment.展开更多
基金JSPS-KOSEF-NSFC A3 Foresight Program(Quantifying and Predicting Terrestrial Carbon Sinks in East Asia:Toward a Network of Climate Change Research).
文摘Aims Recent studies have shown that alpine meadows on the Qinghai-Tibetan plateau act as significant CO_(2)sinks.On the plateau,alpine shrub meadow is one of typical grassland ecosystems.The major alpine shrub on the plateau is Potentilla fruticosa L.(Rosaceae),which is distributed widely from 3200 to 4000 m.Shrub species play an important role on carbon sequestration in grassland ecosystems.In addition,alpine shrubs are sensitive to climate change such as global warming.Considering global warming,the biomass and productivity of P.fruticosa will increase on Qinghai-Tibetan Plateau.Thus,understanding the carbon dynamics in alpine shrub meadow and the role of shrubs around the upper distribution limit at present is essential to predict the change in carbon sequestration on the plateau.However,the role of shrubs on the carbon dynamics in alpine shrub meadow remains unclear.The objectives of the present study were to evaluate the magnitude of CO_(2)exchange of P.fruticosa shrub patches around the upper distribution limit and to elucidate the role of P.fruticosa on ecosystem CO_(2)fluxes in an alpine meadow.Methods We used the static acrylic chamber technique to measure and estimate the net ecosystem productivity(NEP),ecosystem respiration(Re),and gross primary productivity(GPP)of P.fruticosa shrub patches at three elevations around the species’upper distribution limit.Ecosystem CO_(2)fluxes and environmental factors were measured from 17 to 20 July 2008 at 3400,3600,and 3800 m a.s.l.We examined the maximum GPP at infinite light(GPPmax)and maximum Re(Remax)during the experimental time at each elevation in relation to aboveground biomass and environmental factors,including air and soil temperature,and soil water content.Important Findings Patches of P.fruticosa around the species’upper distribution limit absorbed CO_(2),at least during the daytime.Maximum NEP at infinite light(NEPmax)and GPPmax of shrub patches in the alpine meadow varied among the three elevations,with the highest values at 3400 m and the lowest at 3800 m.GPPmax was positively correlated with the green biomass of P.fruticosa more strongly than with total green biomass,suggesting that P.fruticosa is the major contributor to CO_(2)uptake in the alpine shrub meadow.Air temperature influenced the potential GPPat the shrub-patch scale.Remax was correlated with aboveground biomass and Remax normalized by aboveground biomass was influenced by soil water content.Potentilla fruticosa height(biomass)and frequency increased clearly as elevation decreased,which promotes the large-scale spatial variation of carbon uptake and the strength of the carbon sink at lower elevations.
基金funded by the National Natural Science Foundation of China(Grant Nos.91851207,42171138)the Second Tibetan Plateau Scientific Expedition and Research(STEP)Program(Grant No.2019QZKK0503).
文摘Background Microbial communities in different plant compartments are relatively independent entities.However,the influence of environmental factors on the microbial community in different compartments of periglacial plants remains unclear.In this study,we quantified the bacterial communities in the rhizosphere soil,as well as root and leaf endosphere compartments of a periglacial plant,Potentilla fruticosa var.albicans,using high-throughput DNA sequencing.Moreover,we evaluated the impacts of habitat types(glacier terminus zone,moraine ridge,and alpine meadow)on the bacterial community in different plant compartments of Potentilla fruticosa var.albicans.Results Our results showed that habitat type had a significant effect on the alpha diversity(Chao1 richness)of endophytic bacteria,but not on the rhizospheric bacteria.The community composition of rhizospheric and endophytic bacteria was significantly different across the three habitats,and habitat type had a greater effect on the endophytic bacteria than on rhizospheric bacteria.The contribution of rhizosphere soil to the root and leaf endophytes decreased with the transformation of habitats from glacier terminus zone to alpine meadow.In contrast,host selection pressure sequentially increased from the glacier terminus zone to the moraine ridge to the alpine meadow.Furthermore,we found that the bacterial co-occurrence network in the alpine meadow was more modular but had lower complexity and connectedness than that in the glacier terminus zone.The bacterial community was governed primarily by stochastic processes regardless of habitat type.Conclusion This study reveals that the diversity and composition of endophytic bacteria associated with Potentilla fruticosa var.albicans are more affected by habitat types than that of rhizospheric bacteria.Our study also demonstrates that the assembly patterns and co-occurrence patterns of bacterial communities associated with Potentilla fruticosa var.albicans vary by habitat type.These results advance the current understanding of community assembly and ecological interactions of microbial communities associated with periglacial plants.
基金Supported by National Natural Science Foundation of China(No.81460652)Key Research and Development and Achievements Transformation Program of Qinghai Province(No.2018-SF-144)Project Funded by Key Laboratory of Medicinal Animal and Plant Resources of Qinghai-Tibet Plateau in Qinghai Province(No.2017-z-y25)
文摘[Objectives]To study the effects of Fruticosa potentilla L.on the expression of key enzymes and hormones related to glucose and lipid metabolism in T2DM rats.[Methods]The ethyl acetate fraction of 95%methanol extract of F.potentilla(MEE)was administered orally to the T2DM rats,and the level of glucose and expression of insulin,resistin,leptin,glucokinase(GK)and glucose-6-phosphatase(G-6-Pase)in the rats were measured and detected.[Results]In the T2DM rats administered with MEE,the postprandial blood glucose level decreased,the expression levels of resistin,leptin and G-6-Pase were down-regulated,and the expression levels of insulin and GK were up-regulated(P<0.05,P<0.01).[Conclusions]F.potentilla can reduce effectively postprandial blood glucose level,regulate the expression of a variety of enzymes and hormones related to glucose and lipid metabolism and recover partially the insulin level in T2DM rats to achieve resistance to T2DM.
文摘The techniques of cutting propagation of Potentilla fruticosa was studied.The tender stem cuttings and the woody stem cuttings were treated by different concentrations of BBA(0 mg·kg-1,10 mg·kg-1,50 mg·kg-1,100 mg·kg-1,200 mg·kg-1,500 mg·kg-1).The results indicated that the rooting percentage of tender stem cuttings at the concentration of 10 mg ·kg-1BBA was the highest(88.3%),and that of woody stem cuttings treated by the concentration of 50 mg·kg-1BBA was the highest(66.67%).It also indicated that the rooting percentages of the tender stem cuttings were better than those of the woody stem cuttings with same treatment.
