镉胁迫下金银花的生长反应及积累特性

采用水培试验方法,研究了藤本植物金银花在不同浓度镉(Cd)胁迫下的生长反应和积累特性,结果表明,Cd对金银花生长未造成显著影响,甚至低浓度(5和10mg·L-1)Cd具有一定的生长促进作用,表现为植物的株高和叶绿素含量有所增加。当Cd处理浓度达到50mg·L-1时,植物的株高和根长虽有所降低,但与对照相比并无显著差异,且耐性系数均>0.8,表明金银花对Cd具有较强的耐性。当Cd处理浓度为25mg·L-1时,金银花地上部中Cd含量达到286.12μg·g-1,而富集系数均>1,说明金银花具备Cd超富集植物的特征,对Cd污染土壤的修复具有很大的应用潜力。

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<正> "绿色食品"系指经"中国绿色食品发展中心"认定,许可使用"绿色食品"标志的无污染、安全、优质、营养类食品。它具有三个显著的特点:1.出自良好的生态环境; 2.有规范的"从土地到餐桌"全程质量控制措施和标准;3.其标志受法律保护,是集社会效益、环境效益和经济效益为一体的产物,赋予极强的时代特征和浓厚的食品文化内涵.1.绿色食品的开发是社会与经济发展的必然产物,有重要的现实意义现代大工业和城市的发展和进

森林流域洪涝灾害成因分析与防治对策

森林流域洪涝灾害成因分析与防治对策孙铁珩，裴铁璠张吉娜（中国科学院沈阳应用生态研究所）（辽宁省生态学会）本文所述的森林流域是广义的，系指我国典型敏感带以东广大地区。典型敏感带始于东北西部内蒙东部向西南一直延伸到青藏高原东南部。它是干旱、半干旱与湿润、...

植物冻害和氧化胁迫——甘蓝叶冻-融循环中超氧的产生

为检验植物冻害的发生和氧化胁迫这一假说 ,在冰冻前把氮蓝四唑 (NBT)真空渗入到甘蓝叶圆片中 .在叶圆片冻 融循环中NBT被还原为甲　 .把其中的单甲　用乙醇提取出来 ,在分光光度计上比色 ,可作为冻 融循环中产生的氧化胁迫的定量指标 .NBT本身作为氧化剂 ,使冻害稍有增加 .作为冰冻保护剂的二甲基亚砜真空渗入叶圆片使其抗冻性显著增加 ,而NBT还原则显著减少 ,表明二甲基亚砜在保护叶组织免受冻害上的作用和它减缓植物组织氧化胁迫的作用有关 .实验结果支持植物冻害的发生和氧化胁迫有关这一假说 .实验还表明还原NBT的还原剂很可能是超氧阴离子自由基 .

携带叠氮和氨侧基的脂肪族聚酯的合成和表征

含有功能侧基生物降解聚合物的制备在近几年中受到广大研究者的极大关注[1,2].目前已经通过环状碳酸酯与丙交酯(LA)和ε-己内酯(CL)等共聚的方法合成了带有羧基[3~5]和羟基[6,7]等的脂肪族聚酯,并在靶向载体、药物控释及组织工程方面得到了应用[2,8].但有关含侧链氨基的聚合物研究的报道很少,且主要集中在氨基酸NCA单体与LA的嵌段共聚方面[9,10],很少得到侧链氨基的无规共聚物.本文通过丙交酯(LA)与环状碳酸酯单体共聚的方法制备了一种侧链带有溴原子的脂肪族聚酯,并将溴原子用叠氮基团取代,通过Cu(Ⅰ)催化的Click反应将其氨基化,得到了侧链带有氨基的脂肪族聚酯.

Improved performance and stability by an Al/Ni bilayer cathode in organic light-emitting diodes

Al/Ni bilayer cathode was used to improve the electroluminescent (EL) efficiency and stability in N,N'-bis(1-naphthyl)-N,N'-diphenyl-1,1' biphenyl 4,4'-dimaine (NPB)/tris-(8-hydroxyquinoline) aluminum (Alq(3))-based organic light-emitting diodes. The device with LiF/Al/Ni cathode achieved a maximum power efficiency of 2.8 lm/W at current density of 1.2 mA/cm(2), which is 1.4 times the efficiency of device with the state-of-the-art LiF/Al cathode. Importantly, the device stability was significantly enhanced due to the utilization of LiF/Al/Ni cathode. The lifetime at 30% decay in luminance for LiF/Al/Ni cathode was extrapolated to 400 It at an initial luminance of 100 cd/m(2), which is 10 times better than the LiF/Al cathode.

金属离子对鞘磷脂脂双层极性头构象的影响

稀土毒理学以及稀土离子作为钙离子的探针的研究受到普遍关注,人们对稀土离子的生物化学性质进行了广泛研究.作者曾报到了金属离子对DPPC脂质体的极性头构象的影响.鞘磷脂是神经组织细胞膜的重要磷脂组分,和DPPC有相似的极性头.本文利用核磁共振结合Raman光谱研究了金属离子对鞘磷脂脂双层的极性头构象的影响.1 材料和方法

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[Cp3Yb] reacts with HOR (Cp = C5H5; R = CH2CH=CH2, CH2CH2Me) in thf (thf = tetrahydrofuran)at room temperature to give complexes [{Cp2Yb(mu-OR)}2], which are dehydrogenated to yield the new complex [{Cp2Yb(mu-OCH=C=CH2)}2] in refluxing thf solution; the X-ray crystal structure shows that the new complex is dimeric with oxygen atoms as bridging groups.

一类新型的稀土乙腈阳离子配合物[Ln(CH_3CN)_9(AlCl_4)_3]CH_3CN的合成

乙腈是一种给电子能力很弱的配体。过渡金属乙腈阳离子型配合物是一类均相催化剂,可催化烯烃、环烯烃聚合、异构化等反应。1986年Thomas等将金属Eu和NOBF_(?)在CH_3CN中反应制得了合乙腈的稀土阳离子型配合物[Eu(CH_3CN)_3(BF_4)_3]_(?),并指出这一配

Identification and characterization of a myeloid differentiation factor 88 (MyD88) cDNA from Zhikong scallop Chlamys farreri

Myeloid differentiation factor 88 (MyD88) is a universal and essential adapter for the TLR/IL-1R family. In this report, the first mollusk Myd88 ortholog (named as CfMyd88) was cloned from Zhikong scallop (Chlamys farreri). The full-length cDNA of CfMyd88 was of 1554 bp, including a 5 '-terminal untranslated region (UTR) of 427 bp, a polyA tail, and an open reading frame (ORF) of 1104 bp encoding a polypeptide of 367 amino acids containing the typical TLR and IL-1R-related (TIR) domain and death domain (DD). Homology analysis revealed that the predicted amino acid sequence of CfMyd88 was homologous to a variety of previously identified Myd88s with more than 30% identity. The temporal expressions of CfMyd88 mRNA in the mixed primary cultured haemocytes stimulated by lipopolysaccharide (LPS) and peptidoglycans (PGN) were measured by real-time RT-PCR system. The mRNA expression of CfMyd88 decreased after stimulation with both LPS and PGN, and the lowest level was about 1/3 times (at 6 h) and 1/10 times (at 9 h) to that in the control group, respectively. The expression then recovered and was upregulated to two-fold at 9 h after LPS stimulation or to the original level at 12 It after PGN stimulation. The results suggest that the MyD88-dependent signaling pathway exists in scallop and was involved in the defense system. (c) 2007 Elsevier Ltd. All rights reserved.