Cereal straw is one of the most abundant biomass burned in China but its contribution to fine particulates is not adequately understood. In this study, three main kinds of cereal straws were collected from five grain ...Cereal straw is one of the most abundant biomass burned in China but its contribution to fine particulates is not adequately understood. In this study, three main kinds of cereal straws were collected from five grain producing areas in China. Fine particulate matters (PMzs) from the cereal straws subjected to control burnings, both under smoldering and flaming status, were sampled by using a custom made dilution chamber and sampling system in the laboratory. Element carbon (EC) and organic carbon (OC) was analyzed. 141 compounds of organic matters were measured by gas chromatography-mass spectrum (GC-MS). Source profiles of particulate organic matters emitted from cereal straw burnings were obtained. The results indicated that organic matters contribute a large fraction in fine particulate matters. Levoglucosan had the highest contributions with averagely 4.5% in mass of fine particulates and can be considered as the tracer of biomass burnings. Methyloxylated phenols from lignin degradation also had high concentrations in PM2.5, and contained approximately equal amounts of guaiacyl and syringyl compounds. 13-Sitostrol also made up relatively a large fraction of PMz5 compared with the other sterols (0.18%-0.63% of the total fine particle mass). Normal alkanes, PAHs, fatty acids, as well as normal alkanols had relatively lower concentrations compared with the compounds mentioned above. Carbon preference index (CPI) of normal alkanes and alkanoic acids showed characteristics of biogenic fuel burnings. Burning status significantly influenced the formations of EC and PAHs. The differences between the emission profiles of straw and wood combustions were displayed by the fingerprint compounds, which may be used to identify the contributions between wood and straw burnings in source apportionment researches.展开更多
Cereal straw,a human inedible crop byproduct,can be used as a roughage source in ruminants.However,the nutrition density and palatability are very low,limiting its efficient utilization in animal production.This revie...Cereal straw,a human inedible crop byproduct,can be used as a roughage source in ruminants.However,the nutrition density and palatability are very low,limiting its efficient utilization in animal production.This review aims to systematically provide an overview of the limitations of cereal straws,which is crucial for developing new strategies to enhance the efficient use of cereal straws by lactating dairy cows.Evolutionary molecular biology makes it possible to comprehensively understand the limitations of using cereal straw as a roughage source in dairy cows by different techniques,e.g.,multi-omics.Main constraints for utilization of cereal straw and stover in lactating dairy cows include low contents of easily fermented carbohydrates(pectin)and essential amino acids(Met,Phe,and branched-chain amino acids),high content of lignin and silica,and low nutrient digestibility.These cause insufficient supply of the precursors for milk synthesis and result in increased loss of nutrients in feces and urine.Several molecular mechanisms are revealed by multi-omics techniques,including changed amino acid and glucose metabolism,altered rumen microbial composition and function,and differential expression of miRNAs,mRNA,and protein in multi-organs that are associated with milk synthesis.These can be targets of approaches to improve the utilization of cereal straw by dairy cows.In addition,much attention should be given to the efficient countermeasures,including pretreatments by fibrolytic enzymes or steam explosion,dietary formulations such as supplement of pectin,methionine,and branched-chain amino acids,and feeding with other functional feedstuffs,which may improve the feeding and economic value of cereal straw for lactating dairy cows.The newly revealed functional genes(such as BAG3 in the rumen,PC in the liver,CSN1S2 in the mammary gland)and biomarkers(hippuric acid)as well as the integrative signaling and metabolic pathways(phenylalanine metabolism)related to the shortages of cereal straws could be used as nutritional or genetic regulatory targets to improve dairy cow production.展开更多
基金Project supported by the Hi-Tech Research and Development Program (863) of China (No. 2001AA641060 2003AA641040)the National Basic Research Program (973) of China (No. 2002CB410801).
文摘Cereal straw is one of the most abundant biomass burned in China but its contribution to fine particulates is not adequately understood. In this study, three main kinds of cereal straws were collected from five grain producing areas in China. Fine particulate matters (PMzs) from the cereal straws subjected to control burnings, both under smoldering and flaming status, were sampled by using a custom made dilution chamber and sampling system in the laboratory. Element carbon (EC) and organic carbon (OC) was analyzed. 141 compounds of organic matters were measured by gas chromatography-mass spectrum (GC-MS). Source profiles of particulate organic matters emitted from cereal straw burnings were obtained. The results indicated that organic matters contribute a large fraction in fine particulate matters. Levoglucosan had the highest contributions with averagely 4.5% in mass of fine particulates and can be considered as the tracer of biomass burnings. Methyloxylated phenols from lignin degradation also had high concentrations in PM2.5, and contained approximately equal amounts of guaiacyl and syringyl compounds. 13-Sitostrol also made up relatively a large fraction of PMz5 compared with the other sterols (0.18%-0.63% of the total fine particle mass). Normal alkanes, PAHs, fatty acids, as well as normal alkanols had relatively lower concentrations compared with the compounds mentioned above. Carbon preference index (CPI) of normal alkanes and alkanoic acids showed characteristics of biogenic fuel burnings. Burning status significantly influenced the formations of EC and PAHs. The differences between the emission profiles of straw and wood combustions were displayed by the fingerprint compounds, which may be used to identify the contributions between wood and straw burnings in source apportionment researches.
基金the National Basic Research Program of the China Ministry of Science and Technology(2011CB100801)the National Natural Science Foundation of China(No.31472121,31729004)the China Agriculture(Dairy)Research System(CARS-36).
文摘Cereal straw,a human inedible crop byproduct,can be used as a roughage source in ruminants.However,the nutrition density and palatability are very low,limiting its efficient utilization in animal production.This review aims to systematically provide an overview of the limitations of cereal straws,which is crucial for developing new strategies to enhance the efficient use of cereal straws by lactating dairy cows.Evolutionary molecular biology makes it possible to comprehensively understand the limitations of using cereal straw as a roughage source in dairy cows by different techniques,e.g.,multi-omics.Main constraints for utilization of cereal straw and stover in lactating dairy cows include low contents of easily fermented carbohydrates(pectin)and essential amino acids(Met,Phe,and branched-chain amino acids),high content of lignin and silica,and low nutrient digestibility.These cause insufficient supply of the precursors for milk synthesis and result in increased loss of nutrients in feces and urine.Several molecular mechanisms are revealed by multi-omics techniques,including changed amino acid and glucose metabolism,altered rumen microbial composition and function,and differential expression of miRNAs,mRNA,and protein in multi-organs that are associated with milk synthesis.These can be targets of approaches to improve the utilization of cereal straw by dairy cows.In addition,much attention should be given to the efficient countermeasures,including pretreatments by fibrolytic enzymes or steam explosion,dietary formulations such as supplement of pectin,methionine,and branched-chain amino acids,and feeding with other functional feedstuffs,which may improve the feeding and economic value of cereal straw for lactating dairy cows.The newly revealed functional genes(such as BAG3 in the rumen,PC in the liver,CSN1S2 in the mammary gland)and biomarkers(hippuric acid)as well as the integrative signaling and metabolic pathways(phenylalanine metabolism)related to the shortages of cereal straws could be used as nutritional or genetic regulatory targets to improve dairy cow production.