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61.
Identification of ergosterol in vesicular-arbuscular mycorrhizae 总被引:1,自引:0,他引:1
Summary Ergosta-5,7,22-tri-3-enol (ergosterol) was identified by gas chromatography-mass spectrometry in roots of berseem (Trifolium alexandrinum L., cv. Landsorte) and sweet corn (Zea mays L., cv. Honeycomb-F1) infected with the vesicular-arbuscular mycorrhizal (VAM) fungus Glomus intraradices. The fungal-derived compound ergosterol was determined quantitatively in root extracts using reverse-phase high performance liquid chromatography. The concentrations of ergosterol in VAM-infected roots reached 72 g-1 dry material in berseem and 52 g-1 in sweet corn after 80 days of growth, whereas concentrations in non-infected roots remained below 8 g-1 dry weight. Additionally, phytosterols such as -sitosterol, campesterol, and stigmasterol were detected in both infected and non-infected roots. Ergosterol, as a characteristic fungal substance, is proposed as an indicator of fungal biomass in the early stages of VAM infection. 相似文献
62.
采用气相色谱(GC-NPD)分析技术测定除草剂阿灭净在菠萝与土壤中的残留及消解动态结果表明,GC-NPD方法的最小检出量为0.0232ng,菠萝及土壤的最小检出浓度分别为0.002mg/kg和0.005mg/kg,GC-NPD方法回收率分别为87.23%~92.10%和88.80%~93.77%。喷施阿灭净80%WP4800g(a.i/)hm2,处理检测出菠萝与土壤中原始沉积量分别为0.1448~0.1646mg/kg和3.3318~3.5536mg/kg,消解半衰期分别为29.17~29.45d和25.75~30.68d,按阿灭净用量4800g(a.i/)hm2施药菠萝1次,间隔期为10d,菠萝果实残留量2年分别为0.1646mg/kg和0.1448mg/kg,参照欧共体的MRL值0.2mg/kg,按上述阿灭净剂量方法施用菠萝是安全的。 相似文献
63.
Gardini F. Antisari L. Vittori Guerzoni M. E. Sequi P. 《Biology and Fertility of Soils》1991,12(1):1-4
Summary We have developed a simple method for the determination of gaseous compounds that reflect microbial activity in soil, as affected by factors such as the presence of an organic amendment (peat) or a variation in soil moisture. The method is based on a gas chromatographic analysis of the headspace of vials containing the soil under examination. A single gas chromatograph can detect up to 10 different gases. As expected, after peat was added to the soil, CO2 evolution and O2 uptake increased significantly. Positive relationships were found between the evolution of N2O, and soil moisture and the amount of peat added to the soil. Both the these variables influenced the CO2:O2 ratio. The results given by this method show high reproducibility. 相似文献
64.
Curie-point pyrolysis-gas chromatography mass spectrometry with N-selective detection was used to characterize the structure of organic N compounds in four mineral soils. The technique was found suitable for the fast, sensitive, and highly specific identification of N-containing pyrolysis products from whole soils with total N contents between 0.08 and 0.46%. In order to optimize the methodology, one agricultural soil was pyrolyzed at final temperatures of 573, 773, and 973 K. Almost no chemical alterations to identifiable pyrolysis products were observed when the final pyrolysis temperature was increased from 573 to 973 K. More than 50 N-containing pyrolysis products were identified, and were divided into compound classes chracterized by specific molecular-chemical structures. These included pyrroles, imidazoles, pyrazoles, pyridines, pyrimidines, pyrazines, indoles, quinolines, N derivatives of benzene, alkyl nitriles, and aliphatic amines. Three additional soil samples different in origin and N content were analyzed at 773 K and each showed a specific thermosensitive N-selective chromatogram. Many N-containing pyrolysis products were identified in all samples, which indicated general qualitative regularities in the thermal release of N-containing pyrolysis products from the four soils. In the pyrolyzates of the investigated soils a number of compounds were identified, which is usually not detectable in pyrolysis-gas chromatography spectrometry analyses with N-selective detection of plants and microorganisms. Among these were N derivatives of benzene and long-chain alkyl nitriles, which appear to be soil-specific and suggest significant transformations of organic N in soils. Thus, our results contribute to a better understanding of the molecular-chemical structure of unknown N. 相似文献
65.
用液相色谱——紫外检测法和气相色谱——电子捕获检测法分析土壤中超高效除草剂——甲磺隆钠盐的残留量。土壤样品用乙腈提取,提取液用经活化的PT—Si净化柱净化。两种方法回收率分别达到96.9%和97.0%。 相似文献
66.
[目的]弄清废弃植物培养基厌氧消化潜力与特性.[方法]以废弃的植物培养基为发酵原料,以沼气池底部的活性污泥为接种物,在常温条件下进行了批式厌氧消化试验,研究了废弃的植物培养基与接种污泥各处理厌氧消化的产气速率、潜力和产气量.[结果]常温条件下,混合培养基与接种污泥的TS比例为8∶1、浓度12%的处理,产气量最高,为10 391.3 ml,并且发酵天数为5d左右,发酵速度较快,产气效果最好;混合培养基与接种污泥的TS比例为6∶1、浓度8%的处理,原料产气率最高,为0.230 m3/kg,并且发酵天数为4d左右,说明原料被利用的水平高.[结论]该研究为植物组培工厂废弃物的处理和配套沼气工程的工艺设计提供了科学依据. 相似文献
67.
[目的]为更好地勾兑青梅酒,研究青梅浸泡酒、青梅汁、青梅汁发酵酒以及浸泡基酒的香气成分.[方法]采用顶空固相微萃取(HS-SPME)与气相色谱质谱(GC-MS)相结合的方法定性分析浸泡基酒、青梅浸泡酒、青梅汁及青梅汁发酵酒4种样品的香气成分.[结果]试验显示,4个样品依次检测出14、32、17、46种香气成分,香气成分本质的差异决定了其特有的风味和口感.其中,青梅在浸泡过程中产生的特有香气成分为苯甲醛、S-(-)-2-甲基-1-丁醇、苯甲酸乙酯、5-羟甲基糠醛等.青梅汁中特有的香气成分为糠醛、苯乙醇、苯甲醇等.青梅汁发酵酒中产生的主要微量香气成分有苯乙醇(6.941%,峰面积相对百分含量,下同)、异戊醇(6.940%)、辛酸乙酯(3.734%)、癸酸乙酯(2.590%)、己酸乙酯(2.479%)、9-癸烯酸乙酯(2.080%)、5-羟甲基糠醛(1.756%)等.[结论]研究可为青梅酒的品质改善提供科学依据和数据参考. 相似文献
68.
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70.
微纳米气泡(micro-nano-bubbles,MNBs)技术具有比表面积大、气体溶解能力强、表面带有Zeta 电位等特性,在环境治理、清洗、生物医学及农业等领域具有较强研究意义和应用前景。微纳米气泡技术与臭氧(O3)、二氧化碳(CO2)、1- 甲基环丙烯(1-MCP)等气体结合可用于果蔬采后非化学洗涤与保鲜,其中臭氧微纳米气泡、二氧化碳微纳米气泡处理通过减少有害微生物数量达到保鲜目的,1-MCP 微纳米气泡通过抑制乙烯生成延长果蔬保鲜期。本文综述了微纳米气泡技术的研究进展及其在果蔬采后的应用,以期为后续推广应用提供理论依据。 相似文献