共查询到20条相似文献，搜索用时 31 毫秒
1.
Howard EC Henriksen JR Buchan A Reisch CR Bürgmann H Welsh R Ye W González JM Mace K Joye SB Kiene RP Whitman WB Moran MA 《Science (New York, N.Y.)》2006,314(5799):649-652
Flux of dimethylsulfide (DMS) from ocean surface waters is the predominant natural source of sulfur to the atmosphere and influences climate by aerosol formation. Marine bacterioplankton regulate sulfur flux by converting the precursor dimethylsulfoniopropionate (DMSP) either to DMS or to sulfur compounds that are not climatically active. Through the discovery of a glycine cleavage T-family protein with DMSP methyltransferase activity, marine bacterioplankton in the Roseobacter and SAR11 taxa were identified as primary mediators of DMSP demethylation to methylmercaptopropionate. One-third of surface ocean bacteria harbor a DMSP demethylase homolog and thereby route a substantial fraction of global marine primary production away from DMS formation and into the marine microbial food web. 相似文献
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Coral reefs resemble islands of productive habitats where fishes aggregate, forage, and spawn. Although it has been suggested that some reef fishes use biogenic chemicals as aggregation cues, specific chemicals have not been identified. Dimethylsulfoniopropionate (DMSP), a secondary metabolite of many marine algal species, is released during foraging by higher-order consumers. DMSP has been studied intensively for its role in oceanic sulfur cycles and global climate regulation, but its ecological importance to marine fishes is unknown. We present evidence that planktivorous reef fishes will aggregate to experimental deployments of DMSP over coral reef habitats in the wild. 相似文献
4.
三江平原小叶章湿地土壤有机硫矿化特征研究 总被引：2，自引：1，他引：1
利用开放系统培养法,分别在不同温度和水分条件下,研究了三江平原小叶章典型草甸和小叶章沼泽化草甸两种湿地类型的不同层土壤有机硫的矿化特征。结果表明,在不同培养条件下,两种小叶章湿地土壤有机硫的矿化具有一致性:每层土壤有机硫累积矿化量随培养时间的延长而增加,二者之间符合一级动力学方程。上层土壤有机硫的矿化量高于下层土壤,好气培养条件下每层土壤有机硫的累积矿化量均高于淹水条件下矿化量;30℃培养条件下每层土壤有机硫的累积矿化量均高于20℃培养条件下矿化量。温度、水分条件和土壤类型对土壤有机硫的矿化影响显著,但它们之间的交互作用影响不明显。对比两种湿地类型不同层土壤有机硫的矿化,发现在不同培养条件下,小叶章沼泽化草甸土壤有机硫的矿化速率和潜力均高于小叶章典型草甸。 相似文献
5.
【目的】为解决碱性土壤上桑树缺铁黄化问题提供理论依据。【方法】以桑树品种特优2号为试验材料,通过盆栽试验研究施用鸡粪有机肥、硫磺、木质素铁肥对碱性土壤pH值、铁活性及桑树生长、铁素营养的影响。【结果】施用0.670 g/kg硫磺后能明显降低土壤pH值,比对照降低约2个单位。单施硫磺（S2）和硫磺与有机肥混施（S+OF）对桑树生长有明显的促进作用,叶片和茎总重分别比对照增加28.7%和35.9%。施用硫磺（S2）、硫磺与有机肥混施（S+OF）及铁肥与有机肥混施（Fe+OF）均能提高桑树叶片中的活性铁含量。【结论】在碱性土壤中施用硫磺和有机肥能降低土壤pH值,提高土壤中活性铁的含量,促进桑树植株生长,可以作为改善和防治广西地区桑树缺铁黄化的一种较为可行的措施。 相似文献
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WENG Rui SHENG XiaoJing LIU PingXiang ZHANG JiGuang QIU Jing QIAN YongZhong 《中国农业科学》2019,52(18):3199-3206
Garlic is a kind of widely planted agricultural product in China, which has plenty of nutritional and healthy functions, such as antibacterial, anti-inflammatory, and anti-oxidation. These functions are mainly attributed to the organic sulfur compounds, including the flavor precursors, thiosulfinates and thioether volatile compounds. The organic sulfur compounds either have its own biological activities, or multiple compounds work together to produce the same physiological effect. However, considering the poor stability and property diversity of the organic sulfur compounds, the analysis of organic sulfur compounds remains a big challenge. Existing reports are mainly on the determination of several compounds or one group of compounds, and there has been no comprehensive analysis of the organic sulfur compounds in garlic yet. Therefore, in the present review, the analysis methods of the main flavor precursors, thiosulfinates and thioether volatile compounds in garlic were separately discussed and summarized, including the sample pretreatment and detection methods. 相似文献
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有机肥、硫磺和木质素铁对碱性土壤上桑树生长和铁素营养的影响 总被引：1，自引：0，他引：1
【目的】为解决碱性土壤上桑树缺铁黄化问题提供理论依据。【方法】以桑树品种特优2号为试验材料,通过盆栽试验研究施用鸡粪有机肥、硫磺、木质素铁肥对碱性土壤pH值、铁活性及桑树生长、铁素营养的影响。【结果】施用0.670g/kg硫磺后能明显降低土壤pH值,比对照降低约2个单位。单施硫磺（S2）和硫磺与有机肥混施（S＋OF）对桑树生长有明显的促进作用,叶片和茎总重分别比对照增加28.7%和35.9%。施用硫磺（S2）、硫磺与有机肥混施（S＋OF）及铁肥与有机肥混施（Fe＋OF）均能提高桑树叶片中的活性铁含量。【结论】在碱性土壤中施用硫磺和有机肥能降低土壤pH值,提高土壤中活性铁的含量,促进桑树植株生长,可以作为改善和防治广西地区桑树缺铁黄化的一种较为可行的措施。 相似文献
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大蒜是在我国广泛种植和食用的农产品,具有抗菌、抗炎、抗氧化等多种营养健康功能。这些主要得益于大蒜中的有机硫化合物,包括蒜氨酸等风味前体化合物、大蒜素等硫代亚磺酸酯和大蒜烯等硫醚类挥发性化合物等。这些有机硫化合物或各自具有其生物活性,或多种化合物相互协同,共同产生同一种生理功效。但有机硫化合物普遍具有易酶解或稳定性差等特点,且不同类别有机硫化合物的化学性质差异也较大,目前对大蒜中有机硫化合物的分析方法仍然存在局限性,现有报道多是对某类化合物进行总量测定,或是针对个别化合物进行测定,尚未有研究对大蒜中的有机硫化合物进行全面系统的分析。因此,本研究分别对大蒜中主要风味前体化合物、硫代亚磺酸酯和硫醚类挥发性化合物的分析方法进行了分类讨论和综述,包括其样品前处理方法和检测方法。 相似文献
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Spiro CL Wong J Lytle FW Greegor RB Maylotte DH Lamson SH 《Science (New York, N.Y.)》1984,226(4670):48-50
High-resolution x-ray absorption spectroscopy was used to probe the chemical and structural environments of sulfur in coal. Measurement of the sulfur Kedge spectra down to 2472.0 electron volts under nonvacuum conditions was made possible in an all-helium path, and a Stern-Heald type ion chamber was used for fluorescence detection. For a number of selected sulfur-containing minerals and organic model compounds, results show that near-edge spectral features are diagnostic for sulfur in specific organic moieties such as thiols, disulfides, and various heterocyclics, as well as in mineral sulfide and sulfate phases. The spectrum of a model system containing 35 percent iron pyrite and 65 percent benzothiophene was found to match the observed spectral features of a bituminous coal from the eastern United States. 相似文献
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陕西省土壤中硫素的含量与分布 总被引：2，自引：0，他引：2
陕西省主要土壤类型和不同肥力水平土壤耕层含硫量测定结果表明,半干旱、半湿润地区的石灰性土壤和湿润地区非石灰性土壤的含硫量无稳定差异;两种类型土壤硫素状况的主要区别可能是有机硫和无机硫的相对比例,即无机硫在石灰性土壤中所占比例较高。低于多数作物有效硫临界值的土壤主要分布在陕南和陕北地区,关中地区所占比例较小。影响有效硫含量的主要因素是有机质、物理性粘粒和土壤全硫的含量。 相似文献
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[目的]探索建立一种残留分析中有效去除有机硫干扰物的微波加热预处理方法。[方法]对大蒜、洋葱等辛辣蔬菜进行微波处理,考察微波处理时间对样品硫化物干扰的消除效果,并计算方法的回收率和RSD值。[结果]微波时间在60～90 s时,样品硫化物干扰基本消除;各类农药经不同方法处理分析后,回收率均在80%～120%,RSD15%。[结论]该方法简单、快捷,有效解决了辛辣样品中硫化物严重干扰残留测定的问题。 相似文献
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几种不同类型肥料对辣椒产量和品质的影响 总被引：5，自引：0，他引：5
采用田问小区试验的方法,在投入等镀氮磷钾养分情况下,比较4种不同类型肥料(普通肥料、有机菌肥、硫包衣尿素、有机无机配方肥)对辣椒产量和品质的影响.结果表明,与不施肥对照相比,4种肥料的施用均显著增加了辣椒产量,增产幅度为41.5%～65.1%,其中硫包衣尿素处理的辣椒增产最多,且显著高于其他3种肥料处理(P<0.05),另外,硫包衣尿素处理的肥料的农学效率,也显著高于其他3种肥料处理(P<0.05);同时有机菌肥和有机无机配方肥2种处理的辣椒V_C含量显著高于普通肥料处理和不施肥对照;硫包衣尿素辣椒V_C含量和其他肥料处理相比差异不显著;4种肥料处理间的辣椒蛋白质含量无显著差异.综合考虑辣椒产量和品质,硫包衣尿索和磷钾配施能够显著提高辣椒产量,且不降低辣椒品质,同时减少施肥次数,降低综合成本,是值得推荐施用的一种肥料. 相似文献
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吉林省旱地土壤有效硫含量及其与土壤有机质和全氮的关系 总被引：1，自引：0，他引：1
【目的】 明确吉林省旱地土壤有效硫含量状况及其分布差异,为区域作物合理施硫提供依据。【方法】 采集吉林省不同生态区8种主要土壤类型的232个表层（0—20 cm）土壤样品,利用地统计学方法分析有效硫含量的空间分布特征,比较不同类型土壤有效硫含量差异,并建立土壤有效硫和有机质、全氮的相关关系。【结果】 吉林省旱地土壤有效硫含量为5.8—40.7 mg·kg-1,均值为18.1 mg·kg-1,所有样本中缺硫和潜在缺硫的比例分别为27.2%和20.7%。空间分布上,土壤有效硫含量总体呈自东向西逐渐下降趋势,相应的缺硫发生率自东向西逐渐上升。东、中、西三大生态区的土壤有效硫含量均值（缺硫或潜在缺硫发生率）分别为22.3 mg·kg-1（24.2%）、18.1 mg·kg-1（40.0%）和14.3 mg·kg-1（75.6%）。主要分布于东部湿润山区的白浆土、暗棕壤有效硫含量均值分别为22.1和22.0 mg·kg-1,缺硫或潜在缺硫样本分别占15.2%和28.3%;中部半湿润平原区的黑土、冲积土和草甸土有效硫含量均值分别为18.8、17.1和16.2 mg·kg-1,缺硫或潜在缺硫样本占比分别为37.9%、63.5%和55.5%;西部半干旱平原区的黑钙土、风沙土和盐碱土有效硫含量均值分别为11.9、14.0和13.9 mg·kg-1,缺硫或潜在缺硫风险较高,分别占比73.6%、73.3%和75.5%。回归分析结果显示,吉林省旱地土壤有效硫和土壤有机质、土壤全氮均呈显著的对数相关关系,随着土壤有机质和土壤全氮含量增加,土壤有效硫含量也随之提升。【结论】 吉林省旱地土壤有效硫含量在不同区域和土壤类型之间存在显著差异,硫素缺乏现象也较为普遍,47.9%的土壤样本存在缺硫或潜在缺硫问题,特别是中西部地区的风沙土、盐碱土和黑钙土缺硫风险较高,在土壤培肥和作物管理中应注重硫素的补充。 相似文献
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Shewanella putrefaciens, a respiratory facultative anaerobe isolated from the Black Sea, can reduce thiosulfate, sulfite, and elemental sulfur to sulfide readily and quantitatively. This widespread and anaerobically versatile microorganism, which is incapable of reducing sulfate, uses oxidized sulfur intermediates as electron acceptors during the respiratory oxidation of organic matter. Because of its widespread distribution and abundance, it may play a significant role in sulfur and trace metal cycling in the Black Sea and in other marine and freshwater anaerobic environments. 相似文献
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The CIDA (Cometary and Interstellar Dust Analyzer) instrument on the Stardust spacecraft is a time-of-flight mass spectrometer used to analyze ions formed when fast dust particles strike the instrument's target. In the spectra of 45 presumably interstellar particles, quinone derivates were identified as constituents in the organic component. The 29 spectra obtained during the flyby of Comet 81P/Wild 2 confirm the predominance of organic matter. In moving from interstellar to cometary dust, the organic material seems to lose most of its hydrogen and oxygen as water and carbon monoxide. These are now present in the comet as gas phases, whereas the dust is rich in nitrogen-containing species. No traces of amino acids were found. We detected sulfur ions in one spectrum, which suggests that sulfur species are important in cometary organics. 相似文献
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酸性硫酸盐土中硫的形态与酸性表现探讨 总被引：2，自引：0，他引：2
选取４个酸性硫酸盐土剖面共２０个土壤样品进行了硫的分级测定和土壤ｐＨ值的测定,对土壤中硫的形态、含量及其剖面分布规律,以及它们对土壤酸性的贡献进行了探讨,分析结果显示,酸性硫酸盐土中的全硫含量较高,其中土壤硫以无机态硫为主,无机态硫又 以硫铁矿、水溶性和交换性硫为主,有机硫和元素硫含量较低,土壤全硫含量和硫的矿的含量一般具有随剖面浓度的增加而升高的趋势;黄钾铁矾与水溶性硫、交换性硫有类似的剖面变化 相似文献
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为研究不同环境要素作用下重庆农田土壤硫分布特征及其与环境因素的关系,结合野外调查和室内分析,研究了重庆农田土壤全硫的分布特征及其与土壤剖面深度、土壤类型、地形、土地利用方式、土壤pH和有机质之间的关系。结果表明,表层土壤全硫的平均值为262 mg·kg-1,处于我国土壤硫平均水平,高于作物缺硫临界值150 mg·kg-1。全硫含量空间分布在水平方向上呈现渝西、渝东北大于渝东南、渝中的趋势;在垂直方向上,呈现出自上而下逐渐降低的分布特征。全硫含量在不同土壤类型中表现为黄棕壤土最高、潮土最低,在不同地形条件下表现为中山最高、台地最低,在不同土地利用方式下则表现为未开垦农地最高、旱地最低。土壤全硫含量与pH对数呈显著负相关（P<0.01）,与有机质含量对数呈显著正相关（P<0.01）。多元线性逐步回归分析表明,土壤类型和有机质含量是影响土壤全硫含量分布的主要因素,pH、地形、土地利用方式是次要因素。 相似文献
18.
Evidence for Photochemical Formation of H2O2 and Oxidation of SO2 in Authentic Fog Water 总被引：1，自引：0，他引：1
When samples of rain and fog water were exposed to ultraviolet and visible light, reactive transients such as hydrogen peroxide were formed and dissolved organic matter and sulfur dioxide were depleted. These results, in conjunction with those from previous studies, imply that dissolved organic compounds and transition metals such as iron ions are involved in the photochemical formation of hydrogen peroxide and other photooxidants in atmospheric waters. 相似文献
19.
Incubation of forest soils containing sulfate labeled with sulfur-35 showed rapid conversion of the added sulfate to organic sulfur forms by microbial populations. Activity rates were highest in the forest floor, but significant activity was observed throughout the soil profile. The annual potential sulfur incorporation for forest floor and soil combined is estimated to be 30 kilograms per hectare. The metabolism of inorganic sulfate to organic forms can be a major process in the sulfur cycle, influencing sulfate accumulation and mobility in forest ecosystems. 相似文献
20.
A brown polymeric material, produced under simulated Jovian conditions, is composed primarily of cyclic octatomic sulfur, although a range of complex organic compounds is also present. The polymeric sulfur, produced from the ultraviolet photolysis of hydrogen sulfide, exhibits its strongest band at 465 reciprocal centimeters, in fair agreement with the frequency of the unidentified Jovian absorber recently announced by Houck et al. Polymeric octatomic sulfur may be an important constituent of the Jovian clouds. 相似文献