Analysis and characterization of cultivable heavy metal-resistant bacterial endophytes isolated from Cd-hyperaccumulator Solanum nigrum L. and their potential use for phytoremediation

This study investigates the heavy metal-resistant bacterial endophytes of Cd-hyperaccumulator Solanum nigrum L. grown on a mine tailing by using cultivation-dependent technique. Thirty Cd-tolerant bacterial endophytes were isolated from roots, stems, and leaves of S. nigrum L. and classified by amplified ribosomal DNA-restriction analysis into 18 different types. Phylogenetic analysis based on 16S rDNA sequences showed that these isolates belonged to four groups: Actinobacteria (43%), Proteobacteria (23%), Bacteroidetes (27%) and Firmicutes (7%). All the isolates were then characterized for their plant growth promoting traits as well as their resistances to different heavy metals; and the actual plant growth promotion and colonization ability were also assessed. Four isolates were re-introduced into S. nigrum L. under Cd stress and resulted in Cd phytotoxicity decrease, as dry weights of roots increased from 55% to 143% and dry weights of above-ground from 64% to 100% compared to the uninoculated ones. The total Cd accumulation of inoculated plants increased from 66% to 135% (roots) and from 22% to 64% (above-ground) compared to the uninoculated ones. Our research suggests that bacterial endophytes are a most promising resource and may be the excellent candidates of bio-inoculants for enhancing the phytoremediation efficiency.     

4种茄科植物对矿区污染土壤重金属的吸收和富集

采集了湖南及江苏8个矿区或冶炼厂周边4种茄科(Solanaceae)植物及其根际土壤,分析了植物及土壤样品中Cd、Cu、Pb、Mn和Zn 5种重金属浓度.结果表明:番茄(Lycopersicon esculentum)对5种重金属可能有着较强的耐性,但不具有超积累的潜力;刺天茄(Solanum indicum)对Mn、...     

Fe~Ⅱ（EDTA）协同生物转鼓过滤器去除NO的实验研究

采用自行研制的生物转鼓反应器（RDB）处理难溶于水的NO废气,为提高NO的传质系数和去除效率,实验考察了营养液中添加FeⅡ（EDTA）络合剂协同RDB以提高NO去除效率的过程。结果表明,当空床停留时间（EBRT）为0.96 min时,在营养液中添加FeⅡ（EDTA）至100 mg/L后,NO的去除效率从70.78%升至79.26%。未添加FeⅡ（EDTA）时NO去除率随营养液的增加下降,添加FeⅡ（EDTA）至100 mg/L后,去除率随营养液量的增加先上升后下降,且下降速率比上升速率大。随着营养液中FeⅡ（EDTA）浓度从0增加至500 mg/L,实验最佳温度从32.5℃升至47.5℃,但添加FeⅡ（ED-TA）至100 mg/L对实验的最适pH值没有太大影响。     

镇江东部地区土壤中多环芳烃的污染特征及来源解析

分析了镇江东部扬中地区土壤中16种优先控制的多环芳烃（PAHs）污染物的含量特征及污染水平。结果表明,该地区土壤的多环芳烃总量为2．4～49．9μg／Kg,其中荧蒽的含量最高,同我国其他地区相比,其污染水平比较低。5个采样点PAHs含量表明有两个点受工业企业影响,其他3个点具有类似的面源污染即地质成因来源。     

冰雪中持久性有机污染物（POPs）的研究现状

冰雪是地球生态系统中重要的环境组分,它们不仅直接影响着全球的水循环,而且也直接影响着一些物质在不同纬度和海拔上的分布。随着气候的变化,在中低纬度使用和排放的POPs能够挥发到大气中,并伴随着大气的运动向高纬度高海拔地区迁移,这对生态环境造成了极大的威胁。本文主要介绍了持久性有机污染物的危害、历史排放数据,并详细阐述了国内外研究人员对冰雪中POPs的研究现状。     

利用反硝化聚磷菌实现城市污水的脱氮除磷

阐述了反硝化除磷的机理,对现有反硝化除磷工艺进行介绍,并进一步讨论了反硝化除磷的影响因素和未来发展新思路。利用DPBs进行反硝化除磷实现了污水处理的资源化和能源化,代表了当前污水处理可持续发展战略的发展趋势,成为目前脱氮除磷技术研究的热点和重点。     

Mathematical approaches to the analysis of the spatial-age structures of tussock herb species

Some up-to-date methods of analysis of the spatial and age structures of populations, including local population density maps and Ripley’s functions, are described using 20 cenopopulations (CPs) of Adonis vernalis L. as an example. Pregenerative plants have been found to be the most contagious, irrespective of climatic and phytocenotic conditions and land use type. The spatial distribution pattern and structure of A. vernalis are mainly determined by generative plants forming a tussock, irrespective of the climate and vegetation type. This is explained by higher competitiveness of generative plants, which results in a reduced vegetation density at small distances from them (25–50 cm). Within wider areas, plant distribution may be random due to uniformity of local conditions in microhabitats. The formation of distinct plant aggregations is accounted for by insufficient water supply and the intensity and type of anthropogenic impact.     

基于改进层次分析法的化工园区应急能力评估研究

本文采用诱导矩阵的方法对层次分析法进行改进,并将整个计算过程计算机程序化。再利用改进的层次分析法计算出化工园区应急能力各因素的权重。最后根据各因素权重以及各因素的打分情况得到园区的应急能力等级。结果表明：对改进的层次分析法程序化会提高分析速度和精度,并且通过各因素权重分析,对园区的应急能力的改善提出针对性建议。     

基于AHP的校园安全评价指标研究

通过对校园安全隐患的调查和分析,提出应用层次分析法和模糊综合评价所构建的AHP模型对校园安全进行评价,并结合实例给出了应用模型进行评价的步骤和方法。评价结果表明,建立的校园安全评价体系科学、合理、简单易行,具有可行性和指导性。     

底泥厌氧环境和光照对菹草萌发和幼苗生理的影响

通过向底泥中投加不同量的蔗糖使其发生厌氧反应以模拟不同程度的底泥厌氧环境,研究这种环境和光照强度对菹草石芽萌发和幼苗生理作用的影响。实验结果表明,底泥厌氧环境能显著降低菹草石芽的最终萌发率,且低光照会加剧这种趋势;尽管低光照不一定会提高最终的萌发率,但对提早石芽的萌发是有利的。在01%蔗糖投加处理中,幼苗的叶绿素和可溶性蛋白含量最高(平均为250和1928 mg/g FW),其后随投加量的升高而降低,而游离氨基酸的含量却一直呈上升趋势,最高时达到024 mg/g FW ,但低光照却使它下降;可溶性糖含量基本不受底泥厌氧水平的影响,但随着光照减少而降低。随着厌氧水平的增加（从对照到05%蔗糖投加量）,菹草的超氧物歧化酶(SOD)活性呈现上升趋势,但在10%蔗糖投加处理中活性降至最低;而过氧化物酶(POD)活性一直处于下降趋势。研究结论是：底泥厌氧对菹草石芽萌发影响显著,这种影响可能比低光照的限制作用还要重要。轻度的厌氧环境反而能促进菹草幼苗的生理代谢,但随厌氧水平的升高对碳氮平衡和其它生理活动产生不利影响。此外,底泥厌氧环境对菹草幼苗的抗氧化系统也有明显刺激作用。