镉污染土壤的微生物-植物协同修复研究进展

土壤重金属镉(Cd)污染是我国亟待解决的环境问题之一。植物-微生物协同修复因其原位、环保、费用低等特点在修复Cd污染土壤方面展现出较好的应用潜力。微生物通过促进重金属胁迫条件下的植物生长,提高植物对土壤Cd污染的修复效率。本文在阐述修复机理的基础上,对近年来国内外学者采用丛枝菌根真菌、根瘤菌和植物内生菌与植物协同的方法修复土壤Cd污染进行的研究进行了综述,并对今后的发展方向进行了探讨。     

丛枝菌根真菌-植物共生体系在重金属污染土壤修复上的研究进展

概述了丛枝菌根真菌修复土壤重金属的外在表现形式,重点阐述了丛枝菌根真菌对重金属的直接、间接作用,可能的信号因子及基因表达机制,同时展望了未来丛枝菌根真菌可能的应用方向。     

植物-微生物协同修复土壤重金属污染研究进展

土壤重金属污染危害日益严重,在土壤修复技术中,植物与微生物协同修复技术具有显著的优越性。本文介绍了重金属污染土壤修复技术中,植物-微生物协同修复的概念、机理与类型,以及植物-细菌协同修复、植物-菌根真菌协同修复的研究进展,并对该技术未来的研究方向进行了展望,以期为植物-微生物协同修复重金属污染土壤的理论及应用提供依据参考。     

广东某污染土壤修复工程实例及总结

本文以广东某重金属-有机物复合污染土壤修复工程情况为例,概述了目前中国土壤污染现状,并详细介绍了植物-微生物联合修复技术在实际污染土壤修复工程中的应用。实践表明,采用植物-微生物联合修复技术,可以有效降低污染土壤中的重金属和有机物含量。本文还对污染土壤修复技术的发展进行了简要讨论。     

菌根技术在矿山生态修复中的研究

菌根作为真菌菌丝与植物根系的联合体,影响植物种群的竞争能力,使污染环境得以较好的修复.这里对菌根的基本概念进行阐述,并分析其研究现状,在介绍菌根技术在矿山生态修复中应用的基础上,探析目前所存在的问题.     

土壤体系对大气挥发性有机物的净化研究进展

土壤体系是大气挥发性有机物的一个汇,同时其中的有机质、水分、温度以及微生物等对挥发性有机物的净化具有较大的影响。本文综述了土壤体系对挥发性有机物的净化的研究进展以及挥发性有机物在土壤中提取和检测的方法。同时初步阐述了挥发性有机物在空气、土壤、植物等三者之间的关系。最后提出植物-土壤体系联合修复空气污染,通过筛选生长快、净化污染能力强的植物和土壤类型、理化性质、有机质含量高的土壤,对城市地区和工业园区等污染严重空气进行修复。     

矿区复垦土壤微生物群落和功能多样性分析

采用复合基质和丛枝菌根真菌对矿区土壤进行九个月的复垦。为评估复垦效果,利用Biolog方法分析不同复垦时期土壤微生物群落和功能多样性。借助SPSS17．0等软件进行分析,发现微生物群落各项指标在不同复垦阶段的变化明显;对比复垦稳定土和校园绿地土可知,土壤微生物活性及群落功能多样性得到显著改善,并恢复至正常水平。究其原因,是复垦基质中添加30％的污泥以及接种丛植菌根真菌。     

木霉菌协助丛枝菌根真菌对煤矸石分解和绿化的促进效果

为了研究木霉菌协助丛枝菌根真菌对煤矸石的分解与绿化效果的作用,将煤矸石中单施1.5%的丛枝菌根真菌处理,低、中、高三种剂量(0.03%,0.15%,0.30%)的木霉菌分别与1.5%的丛枝菌根真菌混施处理,通过培养皿降解实验和盆栽紫花苜蓿实验进行对比研究,测定了煤矸石的分解率、绿化效果指标以及煤矸石基质的养分、微生物指标.结果表明:单施丛枝菌根真菌能够增加煤矸石的速效磷钾、微生物量碳氮磷、根外菌丝长度,提高过氧化氢酶和磷酸酶活性,最终促进煤矸石的分解和绿化.不同剂量的木霉菌与丛枝菌根真菌混施后,与单施丛枝菌根真菌相比,煤矸石基质的上述指标均有不同程度的提高,最终进一步促进了煤矸石的分解和绿化.其中中剂量的木霉菌协助促进效果最好,使煤矸石分解率、紫花苜蓿的菌根侵染率和紫花苜蓿鲜重分别显著提高了37.98%,39.70%和39.77%,而低剂量和高剂量木霉菌协助促进效果不显著.因此,中剂量木霉菌可协助丛枝菌根真菌促进煤矸石的分解和绿化,具有良好的效果.     

螯合剂与联合物质在植物修复重金属污染土壤的应用研究进展

为提高螯合剂在植物修复重金属污染土壤的效率,诸如菌根、泥炭、植物激素等联合物质被引入螯合剂联合修复中。文章在研究螯合剂及联合物质在植物修复重金属污染土壤的相关文献基础上,主要对当前已经被研究的螯合剂与联合物质的种类及应用概况进行综述,以期为该领域的深入研究提供参考。     

菌根真菌和腐植酸有机肥对樱桃番茄产量和品质的影响

采用盆栽试验,研究了接种丛枝菌根真菌（AMF）和施用腐植酸有机肥对樱桃番茄产量和品质的影响。结果表明：接种菌根真菌能够显著提高植株根系菌根的侵染率和果实干重;接种对品质的改善表现在果实中的可溶性固形物、     

Leaf and root litter of a legume tree as nitrogen sources for cacaos with different root colonisation by arbuscular mycorrhizae

Traditionally cacao (Theobroma cacao L.) is cultivated under legume shade trees, which produce N-rich litter that improves soil organic matter content, microbial activity, and recycles N to the crop. Arbuscular mycorrhiza forming fungi (AMF) are known to play an important role in plant nutrient uptake, yet their role in plant N uptake from organic residues in tropical agroforestry systems is not clear. We studied root and leaf litter of the legume shade tree Inga edulis Mart. as a source of N for cacao and the importance of AMF colonisation in the uptake of litter N under controlled conditions. Leaf and root litter of I. edulis enriched with ¹⁵N was added to cacao pots filled with field soil. Half of the cacao saplings were AMF-inoculated and the soil of non-inoculated saplings was treated with fungicide to suppress AMF. During the 10-week experiment, young cacao leaves were sampled for ¹⁵N analyses and at the end of the experiment whole plants were harvested. Microbial populations in the soil were determined using phospholipid fatty acid (PLFA) analysis, and AMF structures in the roots were quantified. Fungicide treatment decreased AMF structures in roots and increased bacterial populations, but did not affect the decomposition rate of either litter type. Inoculated and non-inoculated cacao saplings used 2.6 and 2.1%, respectively, of N added to the pots in leaf litter and 12.1 and 7.1% of N available in root litter indicating that root litter of I. edulis may be a more efficient N source than leaf litter for cacao. Although the fungicide treatment did not completely suppress AMF in non-inoculated pots, it created sufficient contrast in root AMF colonisation for concluding that AMF significantly enhanced cacao N use from both litter types. The role of root litter of shade trees as a N source in agroforestry should not be neglected.     

Removal of Organic Compounds Containing a Benzene Ring from Water by Adsorptive Micellar Flocculation

The removal of low-molecular-weight benzoic acid (benzoic acid, p-toluic acid, and salicylic acid)-derived and aniline (aniline, 4-chloroaniline, and 2,6-dimethylaniline)-derived organic compounds through adsorptive micellar flocculation (AMF) with anionic surfactants (sodium dodecyl sulfate, SDS) and aluminum sulfate was demonstrated. The interactions between SDS and the organic compounds were studied using ¹H nuclear magnetic resonance (NMR) spectroscopy. Batch AMF experiments were conducted to study the influence of several factors on target pollutant removal. For benzoic acid derivatives, the removal rate was improved by increasing the SDS and Al concentrations, while increases in the concentrations of the organic pollutant tended to decrease the removal rate. The highest removal efficiencies were observed with p-toluic acid (95.4%) > salicylic acid (84.5%) > benzoic acid (76.5%) under weakly acidic conditions due to the greater hydrophobicity of p-toluic acid and the complexation of the Al salts and the salicylic acid. The removal rates of the aniline derivatives were positively related to the SDS concentration and negatively related to the pH. At a pH of 3.0, the highest removal rates of aniline, 4-chloroaniline, and 2,6-dimethylaniline (91.3%, 98.0%, and 97.6%, respectively) were observed. For aniline compounds, charge neutralization between the SDS anions and aniline cations dominated the removal process. These findings provide new insights for the development of further applications of AMF for the removal of benzoic acid and aniline derivatives.     

一种新型阴离子复合磁絮凝剂的合成及其应用

在2-丙烯酰胺-2-甲基丙磺酸(AMPS)和丙烯酰胺(AM)单体共聚反应过程中,引入经过油酸改性的Fe_3O_4颗粒,合成一种新型阴离子复合磁絮凝剂AMF。分析表明,Fe_3O_4以磁核的形式均匀地分散在AMF中,且AMF中含有Fe_3O_4、油酸、AMPS和AM特征吸收峰,有机物含量为70%。混凝沉淀试验结果表明,相对于阴离子型聚丙烯酰胺(APAM)和聚合氯化铝(PAC),AMF在较短的沉淀时间内取得了较高的浊度去除率。     

Synthesis of phosphorus‐containing flame‐retardant antistatic copolymers and their applications in polypropylene

By adjusting the molar ratios of antistatic monomer of octyl phenol ethylene oxide acrylate (denoted as AS), rigid monomer of methyl methacrylate (denoted as MMA), and flame‐retardant monomer of 2‐(phosphoryloxymethyl oxyethylene) acrylate (denoted as FR), a series of flame‐retardant antistatic copolymers poly (octyl phenol ethylene oxide acrylate‐co‐methyl methacrylate‐co‐phosphoryloxymethyl oxyethylene acrylate) (donated as AMF) were synthesized through radical polymerization. Among the obtained copolymers, two copolymers, AMF162 (the feed molar ratio of AS, MMA, and FR as 1 : 6 : 2) and AMF1104 (the feed molar ratio of AS, MMA, and FR as 1 : 10 : 4) with different concentrations were added into polypropylene (PP) to prepare PP‐AMF162 and PP‐AMF1104 series of composites. The thermal stability, limiting oxygen index, the antistatic property, and mechanical properties of PP composites were tested and analyzed. PP‐AMF162 series composites have excellent antistatic effect. When the AMF162 content was equal to or <15 wt %, the impact strength of PP‐AMF162 composites was higher than that of pure PP. The results indicated that copolymer AMF162 was a suitable flame‐retardant and antistatic additive for PP. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41677.     

Effect of the Addition of Waxes on the Crystallization Behavior of Anhydrous Milk Fat

Physicochemical characteristics of lipid-based foods depend, among other factors, on the microstructure and the characteristics of the lipid network formed during crystallization. The objective of this study, was to evaluate the effect of the addition of sunflower oil waxes on the crystallization and melting behavior of anhydrous milk fat (AMF), a lipid with a low content of palmitic and trans-fatty acids. The crystallization and melting behavior of AMF alone and with the addition of 0.25 and 0.5% of waxes was studied using a differential scanning calorimeter. The morphology of the crystallized samples was evaluated with a polarized light microscope. The addition of waxes induced and promoted the crystallization of AMF at high temperatures (>25 °C) as evidenced by lower induction times of crystallization and higher crystallization and melting enthalpies. In addition, smaller crystals and different morphologies were obtained when AMF was crystallized with the addition of waxes. These results suggest that waxes could be used as an additive to modify lipid networks and their physicochemical characteristics, such as texture, smoothness and mouthfeel.     

Chemical and physical characteristics of cocoa butter substitutes, milk fat and malaysian cocoa butter blends

Two ternary systems of confectionery fats were studied. In the first system, lauric cocoa butter substitutes (CBS), anhydrous milk fat (AMF), and Malaysian cocoa butter (MCB) were blended. In the second system, high-melting fraction of milk fat (HMF42) was used to replace AMF and also was blended with CBS and MCB. CBS contained high concentrations of lauric (C_12:0) and myristic (C_14:0) acids, whereas palmitic (C_16:0), stearic (C_18:0), and oleic (C_18:1) acid concentrations were higher in MCB. In addition, AMF and HMF42 contained appreciable amounts of short-chain fatty acids. CBS showed the highest melting enthalpy (143.1 J/g), followed by MCB (138.8 J/g), HMF42 (97.1 J/g), and AMF (72.9 J/g). The partial melting enthalpies at 20 and 30°C demonstrated formation of a eutectic along the binary blends of CBS/MCB, AMF/MCB, and HMF42/MCB. However, no eutectic effect was observed along the binary lines of AMF/CBS and HMF42/CBS. Characteristics of CBS included two strong spacings at 4.20 and 3.8 Å. MCB showed a strong spacing at 4.60 Å and a weak short-spacing at 4.20 Å. On the other hand, AMF exhibited a very weak short-spacing at 4.60 Å and two strong spacings at 4.20 and 3.8 Å, while HMF42 showed an intermediate short-spacing at 4.60 Å and also two strong short-spacings at 4.20 and 3.8 Å. Solid fat content (SFC) analyses at 20°C showed that CBS possessed the highest solid fat (91%), followed by MCB (82.4%), HMF42 (41.4%), and AMF (15.6%). However, at 30°C, MCB showed the highest SFC compared to the other fats. Results showed that a higher SFC in blends that contain HMF does not necessarily correlate with a stronger tendency to form the β polymorph.     

Arbuscular Mycorrhizal Fungi and Plant Chemical Defence: Effects of Colonisation on Aboveground and Belowground Metabolomes

Arbuscular mycorrhizal fungal (AMF) colonisation of plant roots is one of the most ancient and widespread interactions in ecology, yet the systemic consequences for plant secondary chemistry remain unclear. We performed the first metabolomic investigation into the impact of AMF colonisation by Rhizophagus irregularis on the chemical defences, spanning above- and below-ground tissues, in its host-plant ragwort (Senecio jacobaea). We used a non-targeted metabolomics approach to profile, and where possible identify, compounds induced by AMF colonisation in both roots and shoots. Metabolomics analyses revealed that 33 compounds were significantly increased in the root tissue of AMF colonised plants, including seven blumenols, plant-derived compounds known to be associated with AMF colonisation. One of these was a novel structure conjugated with a malonyl-sugar and uronic acid moiety, hitherto an unreported combination. Such structural modifications of blumenols could be significant for their previously reported functional roles associated with the establishment and maintenance of AM colonisation. Pyrrolizidine alkaloids (PAs), key anti-herbivore defence compounds in ragwort, dominated the metabolomic profiles of root and shoot extracts. Analyses of the metabolomic profiles revealed an increase in four PAs in roots (but not shoots) of AMF colonised plants, with the potential to protect colonised plants from below-ground organisms.     

Volatiles Production and Attractiveness to the Mexican Fruit Fly of Enterobacter agglomerans Isolated from Apple Maggot and Mexican Fruit Flies

We investigated two strains of uricase (+) Enterobacter agglomerans, one isolated from the apple maggot fly (AMF) and one from the Mexican fruit fly (MFF), for 1) attractiveness to MFF, and 2) production of attractive chemicals. Regarding chemicals demonstrated attractive to the MFF, the MFF bacterial strain produced more 2,5-dimethylpyrazine, 2-phenylethanol, and indole than the AMF strain, whereas the AMF, but not the MFF strain, produced 3-hydroxybutanone. Cell types that predominated in plated subcultures varied from batch to batch resulting in variation in volatiles production, especially by the AMF strain where indole was sometimes a major component of the odor and at other times not detectable. Despite the greater production of attractive chemicals by the MFF strain, the AMF strain was consistently more attractive and the MFF strain was not different from uninoculated control plates. Statistical analyses indicated negative correlations of attractiveness with production of indole, 2,5-dimethylpyrazine, and 2-phenylethanol, and positive correlation with 3-hydroxybutanone. Results support previous findings with the Mexican fruit fly that showed combinations of attractive chemicals sometimes are not attractive.     

Effect of Lactose Monolaurate and High Intensity Ultrasound on Crystallization Behavior of Anhydrous Milk Fat

Crystallization behavior of anhydrous milk fat (AMF) was studied with the addition of 0.025 and 0.05 % lactose monolaurate (LML). The crystallization behavior was studied at low (ΔT = 3 °C) and high supercooling (ΔT = 6 °C). Polarized light microscopy and laser turbidimetry indicated a delay in crystallization on addition of 0.025 % and 0.05 % LML or Tween 20 to AMF. High intensity ultrasound (HIU) was applied to AMF samples with 0.05 % LML and lower supercooling (T _c = 31 °C; ΔT = 3 °C). HIU application in AMF and AMF + 0.05 % LML induced crystallization (p < 0.05) changing the induction time (τ) at 31 °C from 34.20 ± 1.67 min (AMF) and 47.07 ± 1.27 min (AMF + 0.05 % LML) to 23.23 ± 3.26 min (AMF) and 25.00 ± 0.87 min (AMF + 0.05 % LML). Melting enthalpies (ΔH) of AMF were significantly higher (p < 0.05) than the ones observed for AMF + 0.05 % LML when crystallized without HIU, while enthalpy values increased significantly in AMF + 0.05 % LML samples when crystallized with HIU reaching similar values to the ones obtained for AMF without LML. The viscosity of AMF significantly decreased (p < 0.05) on addition of 0.05 % LML and significantly increased on HIU application.     

Thermal analysis of palm mid-fraction,cocoa butter and milk fat blends by differential scanning calorimetry

Commercial samples of anhydrous milk fat (AMF), Ivory Coast cocoa butter (CB) and palm mid-fraction (PMF) were blended in a ternary system. The melting characteristics of the blends were studied by differential scanning calorimetry (DSC). Results suggest that in the studies of interaction involving more than two fats, partial area (A_i) under the melting peak should be converted to partial enthalpy (ΔH_i) rather than to solid fat index. The ΔH values of the blends decreased as the amount of AMF was increased and increased as the amount of CB was increased. In general, the effect of PMF was less pronounced compared to the effect of the other two fats. Eutectic effects within the ternary system could be detected by measuring the deviation of melting enthalpy by DSC, and from the corresponding values that were calculated for the thermodynamically ideal blends. The deviation reached a maximum when the amount of AMF was about 33%. On the binary line of CB/PMF, the eutectic effect was maximum at about 50–75% PMF. The interaction effect in the system was more noticeable at 30 and 20°C than at lower temperatures. Evaluation at 30°C was preferred because both the effect of AMF in the ternary system and the effect of PMF on the binary line were more readily observed.