Whether the biochar amendment could affect soil organic matter （SOM） turnover and hence soil carbon （C） stock remains poorly understood. Effects of the addition of ^13C-labelled rice straw or its pyrolysed biochar...Whether the biochar amendment could affect soil organic matter （SOM） turnover and hence soil carbon （C） stock remains poorly understood. Effects of the addition of ^13C-labelled rice straw or its pyrolysed biochar at 250 or 350℃ to a sugarcane soil （Ferrosol） on soil labile C （dissolved organic C, DOC; microbial biomass C, MBC; and mineralizable C, MC） and soil organic C （SOC） were investigated after 112 d of laboratory incubation at 25℃. Four treatments were examined as （1） the control soil without amendment （Soil）; （2） soil plus ^13C-labelled rice straw （Soil＋Straw）; （3） soil plus 250℃ biochar （Soil＋B250） and （4） soil plus 350℃biochar （Soil＋B350）. Compared to un-pyrolysed straw, biochars generally had an increased aryl C, carboxyl C, C and nitrogen concentrations, a decreased O-alkyl C and C：N ratio, but similar alkyl C and δ^13C （1 742- 1 877 %）. Among treatments, significant higher DOC, MBC and MC derived from the new C （straw or biochar） ranked as Soil＋Straw〉Soil＋B250〉Soil＋B350, whilst significant higher SOC from the new C as Soil＋B250〉Soil＋Straw≈Soil＋B350. Compared to Soil, DOC and MBC derived from the native soil were decreased under straw or biochar addition, whilst MC from the native soil was increased under straw addition but decreased under biochar addition. Meanwhile, native SOC was similar among the treatments, irrespective of the straw or biochar addition. Compared to Soil, significant higher total DOC and total MBC were under Soil＋Straw, but not under Soil＋B250 and Soil＋B350, whilst significant higher total MC and total SOC were under straw or biochar addition, except for MC under Soil＋B350. Our results demonstrated that the application of biochar to soil may be an appropriate management practice for increasing soil C storage.展开更多
This paper presents an approach which can elucidate automatically the structures of simple organic compounds from their C-13 NMR spectral data by using a computer. Based on a substructure/C-13 NMR chemical shift topol...This paper presents an approach which can elucidate automatically the structures of simple organic compounds from their C-13 NMR spectral data by using a computer. Based on a substructure/C-13 NMR chemical shift topological correlation model, the approach deduces the candidate substructures and the constraints for the substructure assembling from the molecular formula and C-13 NMR spectral data. Then, candidate structures are generated under these constraints by assembling the candidate substructures in a partial superposition manner. Candidate substructures or structures are evaluated once they are generated in order to eliminate those conflicting with the original data as early as possible. The evaluation of a (sub)structure is mainly carried out by simulating its C-13 NMR (sub) spectrum, which is again based on the model, and comparing the simulated spectrum with the original data.展开更多
Kadsura belongs to the Schisandroideae subfamily of Magnoliaceae.Plants from genus Kadsura are widely distributed in the South and Southwest of China.The plants of the genus are widely used as folk medicine for a long...Kadsura belongs to the Schisandroideae subfamily of Magnoliaceae.Plants from genus Kadsura are widely distributed in the South and Southwest of China.The plants of the genus are widely used as folk medicine for a long time in history,with the functions of relieving pain,promoting 'qi' circulation,activating blood resolve stasis,and applications in the treatment of rheumatoid arthritis and gastroenteric disorders.Lignans are the primary characteristic constituents with various biological activities of plants from genus Kadsura.This paper summarized 81 lignans isolated from the plants of genus Kadsura over the past eight years(from 2014 to 2021),which belong to five types:dibenzocyclooctadienes,spirobenzofuranoid dibenzocyclooctadienes,aryltetralins,diarylbutanes and tetrahydrofurans.Each type of these lignans possess typical characteristics in proton magnetic resonance(^(1)H NMR) and carbon-13 nuclear magnetic resonance(^(13)C NMR) spectra,the NMR regularities of these types of lingans were summarized,which provided a useful reference for the structural analysis of lignans.The relationships between lignans and pharmacodynamics were also systematically analyzed,lignans were predicted to be the quality markers(Q-marker) of Kadsura genus.展开更多
基金supported by the National Natural Science Foundation of China (31070549, 31130013 and 40801087)the Research Project of Ministry of Education, China (213019A)
文摘Whether the biochar amendment could affect soil organic matter （SOM） turnover and hence soil carbon （C） stock remains poorly understood. Effects of the addition of ^13C-labelled rice straw or its pyrolysed biochar at 250 or 350℃ to a sugarcane soil （Ferrosol） on soil labile C （dissolved organic C, DOC; microbial biomass C, MBC; and mineralizable C, MC） and soil organic C （SOC） were investigated after 112 d of laboratory incubation at 25℃. Four treatments were examined as （1） the control soil without amendment （Soil）; （2） soil plus ^13C-labelled rice straw （Soil＋Straw）; （3） soil plus 250℃ biochar （Soil＋B250） and （4） soil plus 350℃biochar （Soil＋B350）. Compared to un-pyrolysed straw, biochars generally had an increased aryl C, carboxyl C, C and nitrogen concentrations, a decreased O-alkyl C and C：N ratio, but similar alkyl C and δ^13C （1 742- 1 877 %）. Among treatments, significant higher DOC, MBC and MC derived from the new C （straw or biochar） ranked as Soil＋Straw〉Soil＋B250〉Soil＋B350, whilst significant higher SOC from the new C as Soil＋B250〉Soil＋Straw≈Soil＋B350. Compared to Soil, DOC and MBC derived from the native soil were decreased under straw or biochar addition, whilst MC from the native soil was increased under straw addition but decreased under biochar addition. Meanwhile, native SOC was similar among the treatments, irrespective of the straw or biochar addition. Compared to Soil, significant higher total DOC and total MBC were under Soil＋Straw, but not under Soil＋B250 and Soil＋B350, whilst significant higher total MC and total SOC were under straw or biochar addition, except for MC under Soil＋B350. Our results demonstrated that the application of biochar to soil may be an appropriate management practice for increasing soil C storage.
文摘This paper presents an approach which can elucidate automatically the structures of simple organic compounds from their C-13 NMR spectral data by using a computer. Based on a substructure/C-13 NMR chemical shift topological correlation model, the approach deduces the candidate substructures and the constraints for the substructure assembling from the molecular formula and C-13 NMR spectral data. Then, candidate structures are generated under these constraints by assembling the candidate substructures in a partial superposition manner. Candidate substructures or structures are evaluated once they are generated in order to eliminate those conflicting with the original data as early as possible. The evaluation of a (sub)structure is mainly carried out by simulating its C-13 NMR (sub) spectrum, which is again based on the model, and comparing the simulated spectrum with the original data.
基金financially supported by the National Natural Science Foundation of China (No.81703819, 81874369 and 82074122)Natural Science Foundation of Hunan Province (No.2020JJ4463 and 2020JJ4064)。
文摘Kadsura belongs to the Schisandroideae subfamily of Magnoliaceae.Plants from genus Kadsura are widely distributed in the South and Southwest of China.The plants of the genus are widely used as folk medicine for a long time in history,with the functions of relieving pain,promoting 'qi' circulation,activating blood resolve stasis,and applications in the treatment of rheumatoid arthritis and gastroenteric disorders.Lignans are the primary characteristic constituents with various biological activities of plants from genus Kadsura.This paper summarized 81 lignans isolated from the plants of genus Kadsura over the past eight years(from 2014 to 2021),which belong to five types:dibenzocyclooctadienes,spirobenzofuranoid dibenzocyclooctadienes,aryltetralins,diarylbutanes and tetrahydrofurans.Each type of these lignans possess typical characteristics in proton magnetic resonance(^(1)H NMR) and carbon-13 nuclear magnetic resonance(^(13)C NMR) spectra,the NMR regularities of these types of lingans were summarized,which provided a useful reference for the structural analysis of lignans.The relationships between lignans and pharmacodynamics were also systematically analyzed,lignans were predicted to be the quality markers(Q-marker) of Kadsura genus.
