君子兰化学成分和药理研究进展

君子兰为名贵的观赏性植物,具有广泛的生理及药理活性。君子兰中含有生物碱类、苷类、黄酮类、氨基酸类和无机元素类等多种化学成分。本文综述了君子兰中的化学成分及其在中枢神经系统、心血管系统、抗菌、抗炎、抗病毒和抗肿瘤等方面的药理作用。     

云南清香型烤烟香韵与常规化学成分关系的典型相关分析

[目的]揭示烟草常规化学成分与清香型烤烟香韵间的关系。[方法]应用典型相关分析方法从不同化学成分组合的角度,分析云南烟区127份样品中云南清香型烤烟香韵与其常规化学成分关系。[结果]分析表明,云南清香型烤烟的香韵中以清甜香和青滋香最为明显,但过多的青滋香的出现将会抑制清甜香香韵彰显。化学成分中氯碱比对云南清香型烤烟香韵的形成贡献最大,次之是烟碱和钾。烤烟中烟碱的增加、钾的减少以及氯碱比的降低将有利于云南清香型烤烟中主要由清甜香、清滋香、酸香和坚果香组合形成的烤烟香韵的彰显;反之,则将不利于云南清香型烤烟中典型香韵的形成。[结论]研究可为以后进一步实现品牌使用烟叶原料的可持续发展提供科学参考。     

异樟不同部位精油成分的气相色谱-质谱比较分析1）

采用气相色谱—质谱（ GC/MS）联用技术和保留指数比较法分析了精油成分,以面积归一化法进行定量分析。结果表明：从异樟叶、新枝、老枝、树干、主根和侧根6个不同部位精油中分别检测出了41、51、51、41、39、39种成分;共检测出了74种物质,包括醇类、烃类、醚类、酮类、酯类、醛类及氧化物类化合物,其中醇类20种、烃类40种、醚类6种、酮类1种、酯类3种、醛类1种及氧化物类3种。它们共有成分有20种,包括7种醇类、7种烃类、3种醚类、1种酮类、1种酯类及1种氧化物类。     

化学显色法检测磺胺类药物的残留量

[目的]建立水产品中磺胺类药物残留的化学显色快速检测法。[方法]用甲醇提取水产品中的磺胺类药物残留,采用化学显色法对其进行快速检测。[结果]通过磺胺类药物残留与特定的衍生化试剂反应,形成稳定的紫红色衍生物,检测灵敏度最低可达50μg/kg。[结论]该方法检测限能满足欧盟及我国对磺胺类药物检测的需求,且能够实现水产样品中多种磺胺类药物的现场快速检测。     

畜禽粪便中钾的有效性及其在土壤中的释放特点

为了解畜禽粪便中钾对农作物的生物有效性,对采自杭州市规模化养殖场的牛粪、猪粪、鸭粪和鸡粪等4 种畜禽粪进行了钾的化学形态分析及其土壤培养试验。结果表明：4 种畜禽粪便中全钾含量在4.87~53.40 g/kg 之间,平均为21.50 g/kg。含钾量由高至低依次为猪粪>鸡粪>鸭粪>牛粪。畜禽粪便中的钾具很高的生物有效性,其中,速效钾占全钾的比例平均为49.4%,缓效钾占全钾的比例平均为32.4%。畜禽粪便施入土壤后,其中大部分钾可在短时间内释放成为土壤有效钾。     

红花大金元不同装烟方式的烘烤效果研究

[目的]探究红花大金元不同装烟方式的烘烤效果.[方法]对红花大金元不同部位烟叶烟夹与烟杆2种装烟方式烤后烟的化学成分、用工成本经济效益进行分析.[结果]试验表明,2种装烟方式烤后烟的化学成分差异不大,烟夹的鲜干比大于烟杆,烟夹的用工少于烟杆,烟夹的耗煤耗电高于烟杆,烟夹的上中等烟比例显著高于烟杆,烟夹的均价与单位质量利润高于烟杆.[结论]红花大金元采用烟夹烘烤能减少成本,提高经济效益.     

烤烟烟青虫防治研究进展

介绍了农业防治、化学防治、生物防治、综合防治等烟青虫防治方法,其中生物防治包括昆虫不育及转基因技术、释放天敌、利用性外激素、植物源农药及微生物菌剂,并展望了今后的研究方向.     

化学杂交剂SQ-1诱导小麦雄性不育及与不同小麦品种互作效应的研究

以10个小麦品种和化学杂交剂SQ-1为处理,研究了SQ-1的杀雄效果及不同基因型小麦对SQ-1的反应的遗传差异。结果表明,在参试品种主茎旗叶抽出倒2叶一半,幼穗长为2.5-4.0 cm,穗分化期为药隔期喷施4.0 kg/hm2的SQ-1,诱导雄性不育率达到了99.93%以上。经方差分析,材料间无显著差异。说明化学杂交剂SQ-1与参试小麦不同基因型品种不存在明显的互作效应。     

茉莉花茶加工技术与吸香机理研究现状

为了进一步综合地认识茉莉花茶窨制的工艺本质、完善茉莉花茶窨制技术,本文综述和分析了茉莉花茶加工技术及吸香机理的研究现状,并对后续研究进行了展望。     

Evaluating biodegradability of soil organic matter by its thermal stability and chemical composition

The stability of soil organic matter (SOM) as it relates to resistance to microbial degradation has important implications for nutrient cycling, emission of greenhouse gases, and C sequestration. Hence, there is interest in developing new ways to quantify and characterise the labile and stable forms of SOM. Our objective in this study was to evaluate SOM under widely contrasting management regimes to determine whether the variation in chemical composition and resistance to pyrolysis observed for various constituent C fractions could be related to their resistance to decomposition. Samples from the same soil under permanent pasture, an arable cropping rotation, and chemical fallow were physically fractionated (sand: 2000-50 μm; silt: 50-5 μm, and clay: <5 μm). Biodegradability of the SOM in size fractions and whole soils was assessed in a laboratory mineralization study. Thermal stability was determined by analytical pyrolysis using a Rock-Eval pyrolyser, and chemical composition was characterized by X-ray absorption near-edge structure (XANES) spectroscopy at the C and N K-edges. Relative to the pasture soil, SOM in the arable and fallow soils declined by 30% and 40%, respectively. The mineralization bioassay showed that SOM in whole soil and soil fractions under fallow was less susceptible to biodegradation than that in other management practices. The SOM in the sand fraction was significantly more biodegradable than that in the silt or clay fractions. Analysis by XANES showed a proportional increase in carboxylates and a reduction in amides (protein) and aromatics in the fallow whole soil compared to the pasture and arable soils. Moreover, protein depletion was greatest in the sand fraction of the fallow soil. Sand fractions in fallow and arable soils were, however, relatively enriched in plant-derived phenols, aromatics, and carboxylates compared to the sand fraction of pasture soils. Analytical pyrolysis showed distinct differences in the thermal stability of SOM among the whole soil and their size fractions; it also showed that the loss of SOM generally involved preferential degradation of H-rich compounds. The temperature at which half of the C was pyrolyzed was strongly correlated with mineralizable C, providing good evidence for a link between the biological and thermal stability of SOM.