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131.
氮肥、土壤湿度和温度对稻田土壤甲烷氧化的影响 总被引:2,自引:0,他引:2
Effects of nitrogen fertilizer,soil mosture and temperature and temperature on methane oxidation in paddy soil were investigated under laboratory conditions.Addition of 0.05 g N kg^-1 soil as NH4Cl strongly inhibited methane oxidation and addition of the same rate of KCl also inhibited the oxidation but with more slight effect,suggesting that the inhibitory effect was partly caused by increase in osmotic potential in microorganism cell,Not only NH4^ but also NO3^- greatly affected methane oxidation.Urea did not affect methane oxidation in paddy soil in the first two days of incubation,but strong inhibitory effect was observed afterwards.Methane was oxidized in the treated soil with an optimum moisture of 280 g kg^-1 ,and air-drying inhibited methane oxidation entirely.The optimum temperature of methane oxidation was about 30℃ in paddy soil.while no methane oxidation was observed at 5℃or 50℃。 相似文献
132.
The effects of H2 gas treatment of an agricultural soil cultivated previously with a mixture of clover (Trifolium pratense) and alfalfa (Medicago sativa) on CO2 dynamics and microbial activity and composition were analyzed. The H2 emission rate of 250 nmol H2 g−1 soil h−1 was similar to the upper limit of estimated H2 amounts emitted from N2 fixing nodules into the surrounding soil ([Dong, Z., Layzell, D.B., 2001. H2 oxidation, O2 uptake and CO2 fixation in hydrogen treated soil. Plant and Soil 229, 1-12.]). After 1 week of H2 supply to soil samples simultaneously with H2 uptake net CO2 production declined continuously and this finally led to a net CO2 fixation rate in the H2-treated soil of 8 nmol CO2 g−1 soil h−1. The time course of H2 uptake and CO2 fixation in the soils corresponded with an increase in microbial activity and biomass of the H2-treated soil determined by microcalorimetric measurements, fluorescence in situ hybridization analysis (FISH) and DNA staining (DAPI). Shifts in the bacterial community structure caused by the supply of H2 were recorded. While the H2 treatment stimulated β-and γ-subclasses of Proteobacteria, it had no significant effect on α-Proteobacteria. In addition, FISH-detectable bacteria of the Cytophaga-Flavobacterium-Bacteroides phylum increased in numbers. 相似文献
133.
We evaluate the use of signature fatty acids and direct hyphal counts as tools to detect and quantify arbuscular mycorrhizal (AM) and saprotrophic fungal (SF) biomass in three Hawaiian soils along a natural soil fertility gradient. Phospholipids16:1ω5c and 18:2ω6,9c were used as an index of AM and saprotrophic fungal biomass, respectively. Both phospholipid analysis and hyphal length indicated that the biomass of AMF was greatest at the highest fertility site, and lowest where phosphorus limits plant growth. Saprotrophic fungal biomass did not vary. Hyphal length counts appeared to under-estimate SF abundance, while the phospholipid AMF:SF ratio was in line with expectations. This study indicates that phospholipids may be a valuable and reliable tool for studying the abundance, distribution, and interactions between AM and saprotrophic fungi in soil. 相似文献
134.
研究用辣根过氧化物酶(HRP)催化氧化法处理水中己烯雌酚(DES)的适宜工艺反应条件。试验考察了反应温度、p H和反应物反应计量比等对DES去除率的影响。结果显示,在p H4.5、25℃、[HRP]0/[DES]0为1.000 U/μmol和MH2 O2∶MDES(反应摩尔比)为1∶2的反应条件下,反应3 h,DES去除率可达到92.08%。研究表明,HRP催化H2O2氧化DES反应的适宜条件是:p H4.5左右,温度25℃左右,[HRP]0/[DES]0为1.000 U/μmol,MH2 O2:MDES宜大于0.5;过量H2O2抑制HRP催化活性;DES起始浓度越高,其去除速率越大;以底物DES去除速率表示的最大反应速率Vmax和米氏常数Km分别为74.63 mmol/(L·h)和46.75 mmol/L。 相似文献
135.
136.
137.
Yoich TOMIMURA 《中国林业科技(英文版)》2002,(2)
This paper deals with the chemical components and the chemical structure of lignin of Chinese fir and Poplar I-214 from plantationforest. The results revealed that the contents ofchemical component in heart wood and sapwood were almost the same except ethanol-benzene extract both in Chinese fir and in Poplar I-214, The contents of ash, holocellulose, α -cellulose, pentosan, ethanol-benzene extract and cold-water extract in Poplar I-214 were higher than that in Chinesefir, The content of lignin in Poplar I-214 was lower than that in Chinese flr. Vanillin, vanillic acid and p-hydroxybenzaldehyde were found in Chinesefir while vanillin and vanillic acid, p-hydroxybenzoic acid, syringaldehyde and syringic acid werefound in Poplar I-214 in investigation of the chemical structure of lignin by using nitrobenzene oxidization method. 相似文献
138.
Dhanapati NEUPANEY Jin-bo KIM Makoto ISHIOROSHI Kunihiko SAMEJIMA 《Animal Science Journal》2003,74(5):391-397
The present experiment was performed to determine some functional properties of yak butter lipids such as lipid class composition; conjugated linoleic acid (CLA) composition, differential scanning calorimetric (DSC) analysis, tyrosinase inhibition activity and antioxidant property. Yak butter lipids composition contained 98% triacylglycerols, 0.9% free fatty acids, 0.32% free sterols and 0.27% phospholipids. The CLA content in yak butter was 2.5% and the major portion was of cis‐9 and trans‐11 (90%). The DSC analysis of yak butter lipids showed a similar path for transition temperature as cow butter lipids, although the enthalpy of yak lipid was higher (40.0 mJ/mg) compared to cow butter lipids (32.0 mJ/mg). Melting point of yak butter was observed at 41°C. Yak butter with lactic acid, NaCl, citric acid and ascorbic acid showed pronounced tyrosinase inhibition activity. Vegetable oils blended with yak butter have extended the oxidation induction time. 相似文献
139.
在磷酸盐混合体系中对LF4合金进行微弧氧化,制得了厚达90μm、显微硬度超过1200HV的陶瓷氧化膜。采用电子能谱(EDS)、X射线衍射(XRD)和扫描电镜(SEM)等表面分析方法综合分析了膜层的成分、形貌及结构,并初步讨论了LF4合金微弧氧化膜的形成过程。 相似文献
140.