Due to the Tibetan Plateau’s unique high altitude and low temperature climate conditions,the region’s alpine steppe ecosystem is highly fragile and is suffering from severe degradation under the stress of increasing...Due to the Tibetan Plateau’s unique high altitude and low temperature climate conditions,the region’s alpine steppe ecosystem is highly fragile and is suffering from severe degradation under the stress of increasing population,overgrazing,and climate change.The soil stoichiometry,a crucial part of ecological stoichiometry,provides a fundamental approach for understanding ecosystem processes by examining the relative proportions and balance of the three elements.Understanding the impact of degradation on the soil stoichiometry is vital for conservation and management in the alpine steppe on the Tibetan Plateau.This study aims to examine the response of soil stoichiometry to degradation and explore the underlying biotic and abiotic mechanisms in the alpine steppe.We conducted a field survey in a sequent degraded alpine steppe with seven levels inNorthern Tibet.The plant species,aboveground biomass,and physical and chemical soil properties such as the moisture content,temperature,pH,compactness,total carbon(C),total nitrogen(N),and total phosphorus(P)were measured and recorded.The results showed that the contents of soil C/N,C/P,and N/P consistently decreased along intensifying degradation gradients.Using regression analysis and a structural equation model(SEM),we found that the C/N,C/P,and N/P ratios were positively affected by the soil compactness,soil moisture content and species richness of graminoids but negatively affected by soil pH and the proportion of aboveground biomass of forbs.The soil temperature had a negative effect on the C/N ratio but showed positive effect on the C/P and N/P ratios.The current study shows that degradation-induced changes in abiotic and biotic conditions such as soil warming and drying,which accelerated the soil organic carbon mineralization,as well as the increase in the proportion of forbs,whichwere difficult to decompose and input less organic carbon into soil,resulted in the decreases in soil C/N,C/P,and N/P contents to a great extent.Our results provide a sound basis for s展开更多
Organophosphorus compounds have attracted continuous attention in materials science, agrochemical and pharmaceutical fields due to their unique bioactivities. Thus, the development of novel and robust manners for the ...Organophosphorus compounds have attracted continuous attention in materials science, agrochemical and pharmaceutical fields due to their unique bioactivities. Thus, the development of novel and robust manners for the construction new C—P bond has therefore gained great interests in synthetic organic chemistry. Because of their intrinsic sustainability and green chemistry character, visible light-induced photoredox catalysis has been widely applied in the construction of new chemical bonds, including the formation of C—P bond. In this review, we summarized recent achievements in C—P bond formation reactions initiated by visible light-induced photoredox catalysis, which mainly focusing on the discussion of reaction design and the mechanism.展开更多
目的探讨100 g馒头餐C肽(C-P)释放试验中空腹和2 h C肽(2 h GP)在评估胰岛β细胞功能中的作用。方法收集行100 g馒头餐C-P释放试验且资料完整的2型糖尿病326例,分析空腹C-P、2 h C-P增值、2 h C-P/FCP比值与C-P曲线下面积的关系。结果空...目的探讨100 g馒头餐C肽(C-P)释放试验中空腹和2 h C肽(2 h GP)在评估胰岛β细胞功能中的作用。方法收集行100 g馒头餐C-P释放试验且资料完整的2型糖尿病326例,分析空腹C-P、2 h C-P增值、2 h C-P/FCP比值与C-P曲线下面积的关系。结果空腹C-P、餐后2 h C-P、餐后2 h C-P增值、餐后2 h C-P与空腹C-P比值与C-P曲线下面积均呈正相关,相关程度由强到弱依次为餐后2 h C-P(r=0.97,P<0.05)、2 h C-P(r=0.88,P<0.05)、FCP(r=0.77,P<0.05)、2 h C-P/FCP比值(r=0.21,P<0.05)。结论评估2型糖尿病胰岛β细胞功能时,100 g馒头2 h C-P肽或2 h C-P增值较FCP价值更大,2 h C-P/FCP比值的价值较小。2型糖尿病患者餐后2 h C-P及其增值可用于评估胰岛β细胞功能。展开更多
Partial substitution of chemical fertilizers by organic amendments is adopted widely for promoting the availability of soil phosphorus(P)in agricultural production.However,few studies have comprehensively evaluated th...Partial substitution of chemical fertilizers by organic amendments is adopted widely for promoting the availability of soil phosphorus(P)in agricultural production.However,few studies have comprehensively evaluated the effects of longterm organic substitution on soil P availability and microbial activity in greenhouse vegetable fields.A 10-year(2009–2019)field experiment was carried out to investigate the impacts of organic fertilizer substitution on soil P pools,phosphatase activities and the microbial community,and identify factors that regulate these soil P transformation characteristics.Four treatments included 100%chemical N fertilizer(4 CN),50%substitution of chemical N by manure(2 CN+2 MN),straw(2 CN+2 SN),and combined manure with straw(2 CN+1 MN+1 SN).Compared with the 4 CN treatment,organic substitution treatments increased celery and tomato yields by 6.9-13.8%and 8.6-18.1%,respectively,with the highest yields being in the 2 CN+1 MN+1 SN treatment.After 10 years of fertilization,organic substitution treatments reduced total P and inorganic P accumulation,increased the concentrations of available P,organic P,and microbial biomass P,and promoted phosphatase activities(alkaline and acid phosphomonoesterase,phosphodiesterase,and phytase)and microbial growth in comparison with the 4 CN treatment.Further,organic substitution treatments significantly increased soil C/P,and the partial least squares path model(PLS-PM)revealed that the soil C/P ratio directly and significantly affected phosphatase activities and the microbial biomass and positively influenced soil P pools and vegetable yield.Partial least squares(PLS)regression demonstrated that arbuscular mycorrhizal fungi positively affected phosphatase activities.Our results suggest that organic fertilizer substitution can promote soil P transformation and availability.Combining manure with straw was more effective than applying these materials separately for developing sustainable P management practices.展开更多
基金supported by the State Key Research Development Program of China (Grant 2016YFC0502002)Youth Innovation Research Team Project (LENOM2016Q0003)
文摘Due to the Tibetan Plateau’s unique high altitude and low temperature climate conditions,the region’s alpine steppe ecosystem is highly fragile and is suffering from severe degradation under the stress of increasing population,overgrazing,and climate change.The soil stoichiometry,a crucial part of ecological stoichiometry,provides a fundamental approach for understanding ecosystem processes by examining the relative proportions and balance of the three elements.Understanding the impact of degradation on the soil stoichiometry is vital for conservation and management in the alpine steppe on the Tibetan Plateau.This study aims to examine the response of soil stoichiometry to degradation and explore the underlying biotic and abiotic mechanisms in the alpine steppe.We conducted a field survey in a sequent degraded alpine steppe with seven levels inNorthern Tibet.The plant species,aboveground biomass,and physical and chemical soil properties such as the moisture content,temperature,pH,compactness,total carbon(C),total nitrogen(N),and total phosphorus(P)were measured and recorded.The results showed that the contents of soil C/N,C/P,and N/P consistently decreased along intensifying degradation gradients.Using regression analysis and a structural equation model(SEM),we found that the C/N,C/P,and N/P ratios were positively affected by the soil compactness,soil moisture content and species richness of graminoids but negatively affected by soil pH and the proportion of aboveground biomass of forbs.The soil temperature had a negative effect on the C/N ratio but showed positive effect on the C/P and N/P ratios.The current study shows that degradation-induced changes in abiotic and biotic conditions such as soil warming and drying,which accelerated the soil organic carbon mineralization,as well as the increase in the proportion of forbs,whichwere difficult to decompose and input less organic carbon into soil,resulted in the decreases in soil C/N,C/P,and N/P contents to a great extent.Our results provide a sound basis for s
基金supported by the National Natural Science Foundation of China(21702001)Open fund for Institute of Physical Science and Information Technology,Anhui University and the Start-up Grant from Anhui University
文摘Organophosphorus compounds have attracted continuous attention in materials science, agrochemical and pharmaceutical fields due to their unique bioactivities. Thus, the development of novel and robust manners for the construction new C—P bond has therefore gained great interests in synthetic organic chemistry. Because of their intrinsic sustainability and green chemistry character, visible light-induced photoredox catalysis has been widely applied in the construction of new chemical bonds, including the formation of C—P bond. In this review, we summarized recent achievements in C—P bond formation reactions initiated by visible light-induced photoredox catalysis, which mainly focusing on the discussion of reaction design and the mechanism.
文摘目的探讨100 g馒头餐C肽(C-P)释放试验中空腹和2 h C肽(2 h GP)在评估胰岛β细胞功能中的作用。方法收集行100 g馒头餐C-P释放试验且资料完整的2型糖尿病326例,分析空腹C-P、2 h C-P增值、2 h C-P/FCP比值与C-P曲线下面积的关系。结果空腹C-P、餐后2 h C-P、餐后2 h C-P增值、餐后2 h C-P与空腹C-P比值与C-P曲线下面积均呈正相关,相关程度由强到弱依次为餐后2 h C-P(r=0.97,P<0.05)、2 h C-P(r=0.88,P<0.05)、FCP(r=0.77,P<0.05)、2 h C-P/FCP比值(r=0.21,P<0.05)。结论评估2型糖尿病胰岛β细胞功能时,100 g馒头2 h C-P肽或2 h C-P增值较FCP价值更大,2 h C-P/FCP比值的价值较小。2型糖尿病患者餐后2 h C-P及其增值可用于评估胰岛β细胞功能。
基金supported by the China Agriculture Research System of MOF and MARA(CARS-23-B04)the National Key Research and Development Program of China(2016YFD0201001)。
文摘Partial substitution of chemical fertilizers by organic amendments is adopted widely for promoting the availability of soil phosphorus(P)in agricultural production.However,few studies have comprehensively evaluated the effects of longterm organic substitution on soil P availability and microbial activity in greenhouse vegetable fields.A 10-year(2009–2019)field experiment was carried out to investigate the impacts of organic fertilizer substitution on soil P pools,phosphatase activities and the microbial community,and identify factors that regulate these soil P transformation characteristics.Four treatments included 100%chemical N fertilizer(4 CN),50%substitution of chemical N by manure(2 CN+2 MN),straw(2 CN+2 SN),and combined manure with straw(2 CN+1 MN+1 SN).Compared with the 4 CN treatment,organic substitution treatments increased celery and tomato yields by 6.9-13.8%and 8.6-18.1%,respectively,with the highest yields being in the 2 CN+1 MN+1 SN treatment.After 10 years of fertilization,organic substitution treatments reduced total P and inorganic P accumulation,increased the concentrations of available P,organic P,and microbial biomass P,and promoted phosphatase activities(alkaline and acid phosphomonoesterase,phosphodiesterase,and phytase)and microbial growth in comparison with the 4 CN treatment.Further,organic substitution treatments significantly increased soil C/P,and the partial least squares path model(PLS-PM)revealed that the soil C/P ratio directly and significantly affected phosphatase activities and the microbial biomass and positively influenced soil P pools and vegetable yield.Partial least squares(PLS)regression demonstrated that arbuscular mycorrhizal fungi positively affected phosphatase activities.Our results suggest that organic fertilizer substitution can promote soil P transformation and availability.Combining manure with straw was more effective than applying these materials separately for developing sustainable P management practices.
