A one-year study in a typical red soil region of southern China was conducted to determine atmospheric nitrogen (N) fluxes of typical N compounds (NH3, NH4-N, NO3-N, and NO2) and contribution of three sources (gas, ra...A one-year study in a typical red soil region of southern China was conducted to determine atmospheric nitrogen (N) fluxes of typical N compounds (NH3, NH4-N, NO3-N, and NO2) and contribution of three sources (gas, rainwater, and particles) to N deposition. From July 2003 to June 2004, the total atmospheric N deposition was 70.7 kg N ha-1, with dry deposition accounting for 75% of the total deposition. Dry NH3 deposition accounted for 73% of the dry deposition and 55% of the total deposition. Moreover, NO2 contributed 11% of the dry deposition and 8% of the total deposition. Reduced N compounds (NH4+ and NH3) were the predominate contributors, accounting for 66% of the total deposition. Therefore, atmospheric N deposition should be considered when soil acidification and critical loads of atmospheric deposition on soils are estimated.展开更多
[Objective]The aim was to study the effects of regulation of C/N ratio wheat straw application on tobacco nitrogen,phosphorus and potassium uptake. [Method]Effects of regulation C/N ratio wheat straw application on th...[Objective]The aim was to study the effects of regulation of C/N ratio wheat straw application on tobacco nitrogen,phosphorus and potassium uptake. [Method]Effects of regulation C/N ratio wheat straw application on the flue-cured tobacco yield,output value,nitrogen,phosphorus and potassium content and cumulative uptake of the upper,middle and bottom leaf were studied by using the field plot experiments at Banqiao town,Qujing city,Yunnan Province during the 2008-2009 summer growing seasons. [Result]The results showed that the application of wheat straw alone or after C/N regulation,could significantly increase tobacco production,potassium content,the potassium and nitrogen accumulation amount of leaf,and was more conducive to the potassium uptake of tobacco leaf with wheat straw application after C/N regulation. Compared with non-straw application,the yield of tobacco increased by 6.59%,3.58%,5.98%,8.80% with application of wheat straw alone,wheat straw and vetch,wheat straw and oilseed cake,wheat straw and urea nitrogen,the potassium content in tobacco leaf increased by 3.85%,7.76%,8.82%,11.21%,respectively,the total potassium cumulative amount of leaf increased by 10.71%,11.62%,15.32% ,21.01% and the total nitrogen cumulative amount increased by 9.76%,1.22%,8.14%,14.00%. However,the differences of tobacco leaf nitrogen content among the different treatments were not significant,the phosphorus uptake of tobacco leaf decreased. [Conclusion]application of high C/N ratio wheat straw in flue-cured tobacco production,which should be concerned not only to adjust C/N ratio by adding nitrogen,but also considering additional phosphorus application.展开更多
Objective. To investigate the relationship of plasma homocysteine (Hcy) level to stroke and genetic factor to elevated plasma Hcy level.Methods. The plasma Hcy level was measured by capillary electrophoresis- ultravio...Objective. To investigate the relationship of plasma homocysteine (Hcy) level to stroke and genetic factor to elevated plasma Hcy level.Methods. The plasma Hcy level was measured by capillary electrophoresis- ultraviolet detection and the gene polymorphism of N5, N10 - methylenetetrahydrofolate reductase (MTHFR) was studied with PCR - RFLP assay in 43 patients with cortical cerebral infarction and 42 healthy controls.Results. The plasma Hcy level of the patients ( 19. 3 + 6. 0 μ mol/L) was markedly higher than that of the controls (13.7 + 5.4 μ mol/L) ( t = 4. 16, P ＜ 0. 001). There are 3 genotypes, C/C, C/T and T/T, about base - variation of MTHFR gene at locus 677. The plasma Hcy level of the subjects with T/T genotype was higher than that of subjects with other genotypes. However, the frequencies of each genotype and allele were not significantly different between the patients and the controls.Conclusions. The elevated plasma Hcy level is a risk factor for atherothrombotic cerebral infarction, and is related to the C→T mutation at locus 677 of MTHFR gene.展开更多
In order to systematically investigate the chemical constituents of Citri Reticulatae Folium （leaves of ＇Fuju＇）, an analytical method that included high-performance liquid chromatography, diode array detection, el...In order to systematically investigate the chemical constituents of Citri Reticulatae Folium （leaves of ＇Fuju＇）, an analytical method that included high-performance liquid chromatography, diode array detection, electrospray ionization, and ion-trap time-of-flight mass spectrometry （HPLC-DAD-ESI-MSn） was used to separate and identify the individual chemical components of Citri Reticulatae Folium. As a result, 96 compounds were tentatively identified in this study： including 31 phenolic acids, 4 flavonoid aglycones, 6 flavonoid mono-O-glycosides, 10 flavonoid-O-diglycosides, 5 flavonoid mono-C-glycosides, 5 flavonoid di-C-glycosides, 6 flavonoid O,C-glycosides, 5 （3-hydroxy-3-methylglutaryl） glycosyl flavonoids, 1 flavan-3-ol, and 2 alkaloids. In addition, 21 polymethoxy flavonoids （PMFs） were identified in this paper. Among these compounds, 52 compounds, which were previously found in other Citrus plants, have been identified for the first time in Citri Reticulatae Folium. 15 compounds have not been previously found in the Citrus genus were identified. Moreover, 9 potentially new compounds have also been detected in this paper. This is the first report of the full characterization of chemical components of Citri Reticulatae Folium （leaves of＇Fuju＇） by HPLC-DAD-ESI-MSn.展开更多
The compound-specific stable carbon isotope compositions(δ^(13)C) of leaf wax n-alkanes from two short sediment cores recovered off the Pearl River estuary(PRE) were analyzed to check for their capability of indicati...The compound-specific stable carbon isotope compositions(δ^(13)C) of leaf wax n-alkanes from two short sediment cores recovered off the Pearl River estuary(PRE) were analyzed to check for their capability of indicating decadal scale catchment environmental change. Sedimentary long-chain n-alkanes exhibited an odd-over-even predominance, with a maximum at n-C_(29) or n-C_(31), indicating their leaf wax origin was from vascular plants. The δ^(13)C values of C_(29) and C_(31) n-alkane in all the sediment samples were in the range of -28.8‰ to -31.2‰, consistent with the C_3 plant-dominated vegetation in the Pearl River catchments. The time series of δ^(13)C records from the two cores were comparable and displayed a decreasing trend from the early 20 th century to the end of the 1970s, followed by a reversal in that change leading to continued increase for ca. 15 years. After being corrected for the effect of atmospheric CO_2 rise and δ^(13)C_(atm) decline, the δ^(13)C_(29) records largely retained their raw changing pattern; the post-1980 increase being more conspicuous. The slightly decreasing trend in corrected δ^(13)C records before around 1980 may have been caused by an increase in precipitation, whereas the subsequent increase of δ^(13)C is likely associated with the observed dry climate and/or intensive anthropogenic deforestation. Our results thus demonstrate that leaf wax n-alkanes buried in the sediments off the PRE may well reflect change in the regional climate and/or human activity in the river catchments over the past century.展开更多
The main objective of this work was to compare the applicability of the single leaf(the uppermost leaf L1 and the third uppermost leaf L3) modified simple ratio(mSR705 index) and the leaf positional difference in the ...The main objective of this work was to compare the applicability of the single leaf(the uppermost leaf L1 and the third uppermost leaf L3) modified simple ratio(mSR705 index) and the leaf positional difference in the vegetation index between L1 and L3(mSR705L1-mSR705L3) in detecting nitrogen(N)-overfertilized rice plants.A field experiment consisting of three rice genotypes and five N fertilization levels(0,75,180,285,and 390 kg N/ha) was conducted at Xiaoshan,Hangzhou,Zhejiang Province,China in 2008.The hyperspectral reflectance(350-2500 nm) and the chlorophyll concentration(ChlC) of L1 and L3 were measured at different stages.The mSR705L1 and mSR705L3 indices appeared not to be highly sensitive to the N rates,especially when the N rate was high(above 180 kg N/ha).The mean mSR705L1-mSR705L3 across the genotypes increased significantly(P<0.05) or considerably from 180 to 285 kg N/ha treatment and from 285 to 390 kg N/ha treatment at all the stages.Also,use of the difference(mSR705L1-mSR705L3) greatly reduced the influence of the stages and genotypes in assessing the N status with re-flectance data.The results of this study show that the N-overfertilized rice plants can be effectively detected with the leaf positional difference in the mSR705 index.展开更多
基金Project supported by the Knowledge Innovation Program of the Chinese Academy of Sciences (No. ISSASIP0205)the National Key Basic Research Support Foundation of China (No. 1999011805)+3 种基金the State Key Laboratory of Soil and Sustainable Agriculture, Chinathe Scientific Research Foundation for Returned Overseas Chinese Scholarsthe State Education Ministry of Chinaand the National Natural Science foundation of China (No. 40305019)
文摘A one-year study in a typical red soil region of southern China was conducted to determine atmospheric nitrogen (N) fluxes of typical N compounds (NH3, NH4-N, NO3-N, and NO2) and contribution of three sources (gas, rainwater, and particles) to N deposition. From July 2003 to June 2004, the total atmospheric N deposition was 70.7 kg N ha-1, with dry deposition accounting for 75% of the total deposition. Dry NH3 deposition accounted for 73% of the dry deposition and 55% of the total deposition. Moreover, NO2 contributed 11% of the dry deposition and 8% of the total deposition. Reduced N compounds (NH4+ and NH3) were the predominate contributors, accounting for 66% of the total deposition. Therefore, atmospheric N deposition should be considered when soil acidification and critical loads of atmospheric deposition on soils are estimated.
基金Supported by National Science and Technology Support Program(2006BAD05B06-04)~~
文摘[Objective]The aim was to study the effects of regulation of C/N ratio wheat straw application on tobacco nitrogen,phosphorus and potassium uptake. [Method]Effects of regulation C/N ratio wheat straw application on the flue-cured tobacco yield,output value,nitrogen,phosphorus and potassium content and cumulative uptake of the upper,middle and bottom leaf were studied by using the field plot experiments at Banqiao town,Qujing city,Yunnan Province during the 2008-2009 summer growing seasons. [Result]The results showed that the application of wheat straw alone or after C/N regulation,could significantly increase tobacco production,potassium content,the potassium and nitrogen accumulation amount of leaf,and was more conducive to the potassium uptake of tobacco leaf with wheat straw application after C/N regulation. Compared with non-straw application,the yield of tobacco increased by 6.59%,3.58%,5.98%,8.80% with application of wheat straw alone,wheat straw and vetch,wheat straw and oilseed cake,wheat straw and urea nitrogen,the potassium content in tobacco leaf increased by 3.85%,7.76%,8.82%,11.21%,respectively,the total potassium cumulative amount of leaf increased by 10.71%,11.62%,15.32% ,21.01% and the total nitrogen cumulative amount increased by 9.76%,1.22%,8.14%,14.00%. However,the differences of tobacco leaf nitrogen content among the different treatments were not significant,the phosphorus uptake of tobacco leaf decreased. [Conclusion]application of high C/N ratio wheat straw in flue-cured tobacco production,which should be concerned not only to adjust C/N ratio by adding nitrogen,but also considering additional phosphorus application.
基金This study was supported by"333 Talent Project " funds of Jiangsu Province in 1999.
文摘Objective. To investigate the relationship of plasma homocysteine (Hcy) level to stroke and genetic factor to elevated plasma Hcy level.Methods. The plasma Hcy level was measured by capillary electrophoresis- ultraviolet detection and the gene polymorphism of N5, N10 - methylenetetrahydrofolate reductase (MTHFR) was studied with PCR - RFLP assay in 43 patients with cortical cerebral infarction and 42 healthy controls.Results. The plasma Hcy level of the patients ( 19. 3 + 6. 0 μ mol/L) was markedly higher than that of the controls (13.7 + 5.4 μ mol/L) ( t = 4. 16, P ＜ 0. 001). There are 3 genotypes, C/C, C/T and T/T, about base - variation of MTHFR gene at locus 677. The plasma Hcy level of the subjects with T/T genotype was higher than that of subjects with other genotypes. However, the frequencies of each genotype and allele were not significantly different between the patients and the controls.Conclusions. The elevated plasma Hcy level is a risk factor for atherothrombotic cerebral infarction, and is related to the C→T mutation at locus 677 of MTHFR gene.
文摘In order to systematically investigate the chemical constituents of Citri Reticulatae Folium （leaves of ＇Fuju＇）, an analytical method that included high-performance liquid chromatography, diode array detection, electrospray ionization, and ion-trap time-of-flight mass spectrometry （HPLC-DAD-ESI-MSn） was used to separate and identify the individual chemical components of Citri Reticulatae Folium. As a result, 96 compounds were tentatively identified in this study： including 31 phenolic acids, 4 flavonoid aglycones, 6 flavonoid mono-O-glycosides, 10 flavonoid-O-diglycosides, 5 flavonoid mono-C-glycosides, 5 flavonoid di-C-glycosides, 6 flavonoid O,C-glycosides, 5 （3-hydroxy-3-methylglutaryl） glycosyl flavonoids, 1 flavan-3-ol, and 2 alkaloids. In addition, 21 polymethoxy flavonoids （PMFs） were identified in this paper. Among these compounds, 52 compounds, which were previously found in other Citrus plants, have been identified for the first time in Citri Reticulatae Folium. 15 compounds have not been previously found in the Citrus genus were identified. Moreover, 9 potentially new compounds have also been detected in this paper. This is the first report of the full characterization of chemical components of Citri Reticulatae Folium （leaves of＇Fuju＇） by HPLC-DAD-ESI-MSn.
基金supported by the National Natural Science Foundation of China(Grant Nos.41061160498&41276072)
文摘The compound-specific stable carbon isotope compositions(δ^(13)C) of leaf wax n-alkanes from two short sediment cores recovered off the Pearl River estuary(PRE) were analyzed to check for their capability of indicating decadal scale catchment environmental change. Sedimentary long-chain n-alkanes exhibited an odd-over-even predominance, with a maximum at n-C_(29) or n-C_(31), indicating their leaf wax origin was from vascular plants. The δ^(13)C values of C_(29) and C_(31) n-alkane in all the sediment samples were in the range of -28.8‰ to -31.2‰, consistent with the C_3 plant-dominated vegetation in the Pearl River catchments. The time series of δ^(13)C records from the two cores were comparable and displayed a decreasing trend from the early 20 th century to the end of the 1970s, followed by a reversal in that change leading to continued increase for ca. 15 years. After being corrected for the effect of atmospheric CO_2 rise and δ^(13)C_(atm) decline, the δ^(13)C_(29) records largely retained their raw changing pattern; the post-1980 increase being more conspicuous. The slightly decreasing trend in corrected δ^(13)C records before around 1980 may have been caused by an increase in precipitation, whereas the subsequent increase of δ^(13)C is likely associated with the observed dry climate and/or intensive anthropogenic deforestation. Our results thus demonstrate that leaf wax n-alkanes buried in the sediments off the PRE may well reflect change in the regional climate and/or human activity in the river catchments over the past century.
基金Project (Nos.2007AA10Z102 and 2006AA10Z201) supported by the National High-Tech R & D Program (863) of China
文摘The main objective of this work was to compare the applicability of the single leaf(the uppermost leaf L1 and the third uppermost leaf L3) modified simple ratio(mSR705 index) and the leaf positional difference in the vegetation index between L1 and L3(mSR705L1-mSR705L3) in detecting nitrogen(N)-overfertilized rice plants.A field experiment consisting of three rice genotypes and five N fertilization levels(0,75,180,285,and 390 kg N/ha) was conducted at Xiaoshan,Hangzhou,Zhejiang Province,China in 2008.The hyperspectral reflectance(350-2500 nm) and the chlorophyll concentration(ChlC) of L1 and L3 were measured at different stages.The mSR705L1 and mSR705L3 indices appeared not to be highly sensitive to the N rates,especially when the N rate was high(above 180 kg N/ha).The mean mSR705L1-mSR705L3 across the genotypes increased significantly(P<0.05) or considerably from 180 to 285 kg N/ha treatment and from 285 to 390 kg N/ha treatment at all the stages.Also,use of the difference(mSR705L1-mSR705L3) greatly reduced the influence of the stages and genotypes in assessing the N status with re-flectance data.The results of this study show that the N-overfertilized rice plants can be effectively detected with the leaf positional difference in the mSR705 index.
