中国发展低碳经济的路径选择

绿色技术创新和建立碳排放权市场交易机制是促进低碳经济发展的主要措施。前者的实施主体是企业,后者的实施主体是政府。文章分析了在市场和垄断两种情况下的碳排放交易机制与绿色技术创新结合的结果的变化。分析认为,在市场机制充分发挥作用时,绿色技术创新可以替代碳排放权;在存在垄断的情况下,绿色技术创新对碳排放权具有补充作用;碳排放交易制度与绿色技术创新结合起来是中国发展低碳经济的必然选择;现阶段,碳排放权的分配应以免费分配为主,有偿分配为辅。     

液中放电等离子体降解TNT废液数学模型研究

文章采用液中放电等离子体降解TNT废液,影响降解的因素为放电时间、放电电压、电极间距、气流量、初始浓度、初始电导,采用了无因次方法对降解效率与影响因素之间进行了关联,建立了降解过程的数学模型,并对数学模型进行了分析,得出的结论是:模型方程的置信度为0.71,方程回归系数都显著不等于零,所求的模型是实用的,这为下一步的放大改进工作奠定了良好的基础。     

典型行业中水回用技术及水质评价标准浅析

在水资源日益短缺的今天,中水回用作为开源节流的有效途径,将成为今后的发展趋势。文章介绍了电子、汽车制造、啤酒等几个典型行业中水回用技术,并对回用水质的评价标准如何制定作出探讨。     

Occurrence of human pathogenic bacteria carrying antibiotic resistance genes revealed by metagenomic approach: A case study from an aquatic environment

Antibiotic resistance genes(ARGs), human pathogenic bacteria(HPB), and HPB carrying ARGs are public issues that pose a high risk to aquatic environments and public health. Their diversity and abundance in water, intestine, and sediments of shrimp culture pond were investigated using metagenomic approach. A total of 19 classes of ARGs, 52 HPB species, and 7 species of HPB carrying ARGs were found. Additionally, 157, 104, and 86 subtypes of ARGs were detected in shrimp intestine, pond water, and sediment samples, respectively. In all the samples, multidrug resistance genes were the highest abundant class of ARGs. The dominant HPB was Enterococcus faecalis in shrimp intestine, Vibrio parahaemolyticus in sediments, and Mycobacterium yongonense in water, respectively. Moreover, E. faecalis(contig Intestine_364647)and Enterococcus faecium(contig Intestine_80272) carrying efr A, efr B and ANT(6)-Ia were found in shrimp intestine, Desulfosaricina cetonica(contig Sediment_825143) and Escherichia coli(contig Sediment_188430) carrying mex B and APH(3′)-IIa were found in sediments, and Laribacter hongkongensis(contig Water_478168 and Water_369477), Shigella sonnei(contig Water_880246),and Acinetobacter baumannii(contig Water_525520) carrying sul1, sul2, ere A, qac H, OXA-21, and mph D were found in pond water. Mobile genetic elements(MGEs) analysis indicated that horizontal gene transfer(HGT) of integrons, insertion sequences, and plasmids existed in shrimp intestine, sediment, and water samples, and the abundance of integrons was higher than that of other two MGEs. The results suggested that HPB carrying ARGs potentially existed in aquatic environments, and that these contributed to the environment and public health risk evaluation.     

Effects of nitrogen dioxide and its acid mist on reactive oxygen species production and antioxidant enzyme activity in Arabidopsis plants

Nitrogen dioxide (NO₂) is one of the most common and harmful air pollutants. To analyze the response of plants to NO₂ stress, we investigated the morphological change, reactive oxygen species (ROS) production and antioxidant enzyme activity in Arabidopsis thaliana (Col-0) exposed to 1.7, 4, 8.5, and 18.8 mg/m³ NO₂. The results indicate that NO₂ exposure affected plant growth and chlorophyll (Chl) content, and increased oxygen free radical (O₂⁻) production rate in Arabidopsis shoots. Furthermore, NO₂ elevated the levels of lipid peroxidation and protein oxidation, accompanied by the induction of antioxidant enzyme activities and change of ascorbate (AsA) and glutathione (GSH) contents. Following this, we mimicked nitric acid mist under experimental conditions, and confirmed the antioxidant mechanism of the plant to the stress. Our results imply that NO₂ and its acid mist caused pollution risk to plant systems. During the process, increased ROS acted as a signal to induce a defense response, and antioxidant status played an important role in plant protection against NO₂/nitric acid mist-caused oxidative damage.     

Evolution characteristics and transcriptional responses to multiple stresses of NAC genes in Chenopodium quinoa and its ancestral diploid species北大核心CSCD

NAC是一类广泛参与调控植物在生物和非生物胁迫下防御应答的转录因子.基于系统的比较基因组学研究方法,对藜麦Chenopodium quinoa的NAC基因进行进化与多个生物和非生物逆境下的应答研究.在藜麦C.quinoa、祖先二倍体Chenopodium pallidicaule和Chenopodium suecicum基因组中分别共鉴定得到106、54和54个NAC基因.染色体定位数据表明藜麦基因组中18个NAC基因涉及串联倍增事件.3个物种NAC基因的系统进化树证明藜麦基因组中存在NAC基因的倍增与丢失.藜麦分别和C.pallidicaule和C.suecicum之间同源基因组模块的对应数目关系进一步证明藜麦保留了相当数量的祖先二倍体NAC基因,是其NAC基因倍增的主要动力.此外,藜麦NAC基因在干旱、高温、盐、低磷胁迫和GCFSV侵染下的表达模式被阐明;大量NAC基因被显著地诱导表达,推测其参与了藜麦在生物和非生物胁迫下的防御应答反应.本研究结果为藜麦的遗传育种提供了优良的候选NAC基因.(图7参26)     

Protective effect of exogenous nitric oxide and salicylic acid on the photosynthetic apparatus of tomato seedling leaves under NaCl stress北大核心CSCD

Using the tomato variety 'Qin Feng Bao Guan' as experimental material, and by the hydroponics nutrient solution method, we investigated the effects of single and compound applications of nitric oxide (NO) donor sodium nitroprusside (SNP) and salicylic acid (SA) on the gas exchange and chlorophyll fluorescence parameters, RuBisCO activation, CO2 response curve, photosynthetic pigment content, and xanthophyll cycle in seedling leaves under an NaCl stress of 100 mmol/L. The main findings were as follows: (1) Single or combined applications of SNP and SA could increase the net photosynthetic rate (Pn), stomatal conductance (Gs), PS II maximal photochemistry efficiency (Fv/Fm), antenna conversion efficiency (Fv'/Fm'), practical photochemical efficiency (φPS?), photochemical fluorescence quenching coefficient (qP), and chlorophyll fluorescence decay rate (Rfd) of tomato seedling leaves at different rates, and significantly reduce the intercellular CO2 concentration (Ci), original fluorescence (Fo), and PS II non-photochemical fluorescence quenching coefficient (NPQ), after NaCl stress treatment. The strongest effect was observed after applying a combination of SNP and SA. (2) Under NaCl stress, the decrease of CO2 carboxylation efficiency (CE), RuBP maximum regeneration rate (Jmax), RuBisCO and its activation enzyme activity, and the maximum carboxylation rate (Vc max) in tomato seedling leaves could be effectively relieved by SNP, SA, or SNP + SA applications; however, SNP + SA treatment had the strongest effect. (3) Single or combined applications of SNP and SA could effectively inhibit the decrease of the contents of photosynthetic pigments (chlorophyll a, chlorophyll b, and carotenoids), the ratio of chlorophyll a and chlorophyll b, xanthophyll cycle pool size (V + A + Z), and the increase of the de-epoxidation extent of the xanthophyll cycle (A + Z)/(V + A + Z). The combined application of SNP and SA had the most prominent effect. In conclusion, the heat dissipation of the antenna, which is dependent on the xanthophyll cycle, is not the physiological mechanism for the protection of the photosynthetic apparatus by exogenous NO, SA alone, or compound treatment in tomato seedling leaves under NaCl stress. It is the main reason for the increase of photosynthetic function and enhanced salt tolerance of leaves tomato seedlings that the protection of PS II and its primary electron acceptor quinone (QA) downstream electron transfer patency, and the improvement of CO2 assimilation activity by application of exogenous NO, SA alone, or a combination of the two; synergistic effects were observed after using a combination of SNP and SA. © 2018 Science Press. All rights reserved.     

An emerging market for groundwater remediation in China: Policies,statistics, and future outlook

There is a rapidly emerging and potentially huge market for the remediation of contaminated groundwater in China. The Chinese government published a Water Action Plan in April 2015, a Soil Action Plan in May 2016, and a draft Soil Pollution Prevention and Control Law in June 2017. All of these new policies and regulations put pressures on local governments and contaminated site owners, obliging them to conduct site investigation and to cleanup contaminated groundwater. The Chinese population in northern regions heavily depend on groundwater, with nearly 70% of water supply coming from aquifer sources in the Beijing-Tianjin-Hebei region. However, poor groundwater quality due to natural geochemical background and anthropogeic pollution is a serious concern, with poor or very poor quality water observed in nearly 80% of groundwater monitoring wells in 17 northern provinces. Shallow groundwater in many areas has been contaminated by toxic pollutants such as heavy metals and chlorinated organic compounds. There is an urgent need to better understand the situation and to conduct groundwater remediation at contaminated sites. The Chinese government is investing heavily in the research and development for groundwater remediation, which is expected to greatly add to the quality and quantity of groundwater remediation projects in the near future.     

火花放电条件下CS_2转化为COS的反应

利用火花放电技术模拟研究了自然界闪电作用下CS₂转化为COS的反应. 结果表明, 放电条件(电压3000 V)下CS₂(初始分压为1.33×10³ Pa)能与空气(25 ℃, 10³ Pa)中的氧气、水蒸气作用, 转化为COS以及其他含硫含碳产物(CO、CO₂、SO₂等); CS₂初始分压、水蒸气和放电时间等因素对COS生成量有明显的影响. 并在实验基础上结合多种理论, 探讨了相关过程的大气闪电反应机理. 这些结果可为自然界闪电条件下的硫循环、碳循环过程的研究提供重要依据.