Effect of composite amendments on physicochemical properties of copper tailings repaired by herbaceous plants

Environmental Science and Pollution Research - Phytoremediation is considered to be the most environmentally friendly green restoration technology for dealing with mine waste. Adding amendments can...     

MBR在橡胶废水处理中的应用

橡胶废水具有含盐量高、色度高、有机污染成分含量高且难于生化降解等特点。膜生物反应器(MBR)技术的核心是生化处理加微滤膜过滤,通过将MBR技术应用于橡胶废水处理的实践表明,该技术对COD、氨氮、磷酸盐的平均去除率都达到了85%以上,再辅之以药剂处理后,降低了色度和难降解有机物含量,出水水质完全符合排放标准的要求,是一种解决橡胶污水处理难题的有效途径。     

Responses of earthworm to aluminum toxicity in latosol

Excess aluminum (Al) in soils due to acid rain leaching is toxic to water resources and harmful to soil organisms and plants. This study investigated adverse impacts of Al levels upon earthworms (Eisenia fetida) from the latosol (acidic red soil). Laboratory experiments were performed to examine the survival and avoidance of earthworms from high Al concentrations and investigate the response of earthworms upon Al toxicity at seven different Al concentrations that ranged from 0 to 300 mg kg^?1 over a 28-day period. Our study showed that the rate of the earthworm survival was 100 % within the first 7 days and decreased as time elapsed, especially for the Al concentrations at 200 and 300 mg kg^?1. A very good linear correlation existed between the earthworm avoidance and the soil Al concentration. There was no Al toxicity to earthworms with the Al concentration ≤50 mg kg^?1, and the toxicity started with the Al concentration ≥100 mg kg^?1. Low Al concentration (i.e., <50 mg kg^?1) enhanced the growth of the earthworms, while high Al concentration (>100 mg kg^?1) retarded the growth of the earthworms. The weight of earthworms and the uptake of Al by earthworms increased with the Al concentrations from 0 to 50 mg kg^?1 and decreased with the Al concentrations from 50 to 300 mg kg^?1. The protein content in the earthworms decreased with the Al concentrations from 0 to 100 mg kg^?1 and increased from 100 to 300 mg kg^?1. In contrast, the catalase (CAT) and superoxide dismutase (SOD) activities in the earthworms increased with the Al concentrations from 0 to 100 mg kg^?1 and decreased from 100 to 300 mg kg^?1. The highest CAT and SOD activities and lowest protein content were found at the Al concentration of 100 mg kg^?1. Results suggest that a high level of Al content in latosol was harmful to earthworms.     

CO2倍增和施氮对水稻不同生长期土壤反硝化细菌丰度的影响

随着全球气候变化的不断加剧,大气CO₂浓度呈明显增加趋势,这将间接影响土壤-植物-微生物系统的氮循环过程.为研究典型水稻土壤反硝化细菌对CO₂浓度升高的响应规律和机制,借助水稻密闭培养箱,运用实时荧光定量聚合酶链式反应（Real-Time qPCR）分子技术,设置不施氮（0 mg/kg）和常规施氮（100 mg/kg）2个处理,研究CO₂倍增对水稻不同生长期土壤关键反硝化功能细菌（narG、nirK和nirS型）丰度的影响.结果表明:①在2种施氮水平,CO₂倍增显著促进了水稻分蘖期、孕穗期、扬花期和成熟期水稻根系生长（增幅为2.96%~28.4%）、地上部生物量增加（增幅为7.1%~107.3%）以及成熟期籽粒干质量的增加（增幅为19.5%和38.0%）,具有显著的增产效应.②反硝化细菌丰度对CO₂倍增的响应与生育期及施氮水平有关,CO₂倍增在2个施氮水平均抑制分蘖期反硝化细菌的繁殖,显著增加孕穗期反硝化细菌数量;在水稻扬花期,CO₂倍增促进了施氮处理narG和nirS型反硝化细菌数量的增加,在成熟期抑制未施氮处理下narG、nirK和nirS型反硝化细菌的生长.另外,narG、nirK、nirS型反硝化细菌丰度整体表现为narG > nirS > nirK,且随水稻的生长,其在成熟期的丰度均呈降低趋势.nirK和nirS基因同属亚硝酸还原酶,但nirS基因丰度高于nirK,且对CO₂倍增和施氮的响应有所差异.研究显示,CO₂倍增可显著增加水稻生长和产量,不同施氮水平对稻田土壤反硝化细菌丰度的影响存在差异.      

识别黄山药、穿龙薯蓣和盾叶薯蓣的分子标记建立

在对黄山药、穿龙薯蓣和盾叶薯蓣的psbA-trnH片段序列分析的基础上,根据3种薯蓣在该片段上的特征序列位点设计了用于识别3种薯蓣的寡核苷酸片段,并作为PCR反应的引物,将3种薯蓣的特征标记引物与psbAf-trn-Hr配合使用建立了识别3种薯蓣的显性和共显性两种检测方式,辅以NaOH碱法快速提取薯蓣干燥根茎总DNA,为3种薯蓣相互间快速、准确的鉴别创造了条件.图3表2参9     

The negative effects of cadmium on Bermuda grass growth might be offset by submergence

Revegetation in the water-level-fluctuation zone (WLFZ) could stabilize riverbanks, maintain local biodiversity, and improve reservoir water quality in the Three Gorges Reservoir Region (TGRR). However, submergence and cadmium (Cd) may seriously affect the survival of transplantations. Bermuda grass (Cynodon dactylon) is a stoloniferous and rhizomatous prostrate weed displaying high growth rate. A previous study has demonstrated that Bermuda grass can tolerate deep submergence and Cd stress, respectively. In the present study, we further analyzed physiological responses of Bermuda grass induced by Cd-and-submergence stress. The ultimate goal was to explore the possibility of using Bermuda grass for revegetation in the WLFZ of China’s TGRR and other riparian areas. The Cd-and-submergence-treated plants had higher malondialdehyde contents and peroxidase than control, and both increased with the Cd concentration increase. All treated plants catalase activity increased with the experimental duration increases, and their superoxide dismutase also gradually increased with the Cd concentration from 1 day to 15 days. Total biomass of the same Cd-and-submergence plants increased along the experimental duration as well. Plants exposed to Cd-and-submergence stress showed shoot elongation. The heights of all treated plants were taller than those of the control. Leaf chlorophyll contents, maximum leaf length, and soluble sugars contents of all the Cd-and-submergence-treated plants were more than those of the untreated control. Although Cd inhibits plants growth, decreases chlorophyll and biomass content, and with the submergence induced the leaf and shoot elongation, more part of the Cd-and-submergence stress plants appeared in the air, exhibited fast growth with maintenance of leaf color, which guaranteed the plants’ photosynthesis, and ensured the total biomass and carbohydrate sustainability, further promoting Cd-and-submergence tolerance. The results imply that the negative effects of cadmium on Bermuda grass growth might be offset by submergence.     

模拟酸雨及其活化Al~（3＋）构成的复合污染对中小型土壤动物的毒杀效果

酸雨可引起土壤中铝离子的活化而造成铝毒问题,因此酸雨及其活化的金属铝离子势必造成对土壤中小型动物的复合污染与影响。为此,通过室内模拟试验,研究3种优势土壤动物直接暴露在4种不同酸度的模拟酸雨和4种不同铝离子浓度梯度组合而构成的复合污染处理条件下的死亡率,以探明酸雨通过降低土壤酸度同时活化Al3＋对土壤动物的叠加影响效应。研究结果表明：弹尾目、线虫、蜱螨目等土壤动物直接暴露在酸水和铝离子的复合溶液中,其死亡率总体上均会随着酸水pH值的降低和Al3＋离子浓度的升高而增加。通过单因素和双因素方差分析还发现,不同类群的土壤动物对模拟酸雨pH和溶液中Al3＋含量的敏感性各不相同,其中酸水和铝离子复合胁迫对线虫和蜱螨目动物死亡率的影响并没有表现出明显的交互作用,但对弹尾目土壤动物死亡率存在显著的交互作用影响。     

飞机草的繁殖能力与种子的萌发特性

飞机草（Chromolaena odorata）是一种入侵性极强的外来杂草,现正在我国南部地区迅速传播,其繁殖特性与种子萌发对环境条件的适应能力是成功入侵扩散的前提。采用野外调查与室内试验相结合的方法,研究了飞机草的繁殖能力与种子的萌发特性。结果表明,飞机草能够进行无性繁殖,但其有性生殖能力更强,成熟植株的种子生产量高,种子质量轻,并且具有冠毛等附属结构。环境因子能够影响飞机草种子的萌发,其萌发的最适温度约为28℃,萌发过程中不需要特别的养分供应,并且能够忍耐一定程度的干旱胁迫。酸性环境能够促进飞机草种子的萌发,但当pH降至2.0时,其发芽率显著降低。掩埋处理能够抑制飞机草种子的萌发,当埋藏深度达3.0 cm时,所有的种子均不能正常萌发与出苗。     

穿龙薯蓣、黄山药和盾叶薯蓣psbA-trnH片段序列分析

为研究薯蓣叶绿体psbA-trnH片段遗传多样性,探讨该片段用于中药穿龙薯蓣、黄山药和盾叶薯蓣种间分子鉴别和系统学研究中的意义,我们对不同类群薯蓣种的叶绿体psbA-trnH基因间区进行PCR扩增并测序,获得了该区间的完整序列,所得序列用软件MEGA3.0进行相关分析.穿龙薯蓣的psbA-trnH片段全长274bp,黄山药全长279bp,盾叶薯蓣植物个体内的叶绿体DNA则有两种psbA-trnH片段,长度分别为241bp和503bp.经MEGA3.0软件分析,3种薯蓣种间psbA-trnH片段序列的遗传距离(p-distance)为0.00350~0.04545,各个薯蓣种内的不同类群该序列无差异.用UPGMA法根据psbA-trnH序列的遗传距离建立系统发生树,聚类结果和形态分类相符.所得结果显示,psbA-trnH片段序列在所研究的3种薯蓣种内保守,在种间具有明显的较大差异,而3种薯蓣及薯蓣属的系统发生关系尚须进一步研究.图3表2参6     

膜生物反应器处理一氧化氮废气研究

采用中空纤维膜生物反应器处理一氧化氮(NO)废气,考察系统长时间运行稳定性、闲置后恢复生物降解情况,研究了进气浓度、停留时间、液体喷淋量及pH对氮氧化物净化效率与传质系数的影响.膜生物反应器实现了100 d长时间高效稳定运行,闲置38 d后能在l周内迅速恢复;膜生物反应器对NO的净化效率最高可达93.8％,适宜运行条件:液体pH值为7.4,气体停留时间为32 s,液体喷淋量为3 mL· min-,其对应的膜传质系数为7.39×10-5 mol·m-2·s-l.膜生物反应器提高系统的NO传质效率,增强了降解效果,具有较好的抗负荷冲击能力,能适应非连续性生产的要求.