Wu FY Yu XZ Wu SC et al.. Phenanthrene and pyrene uptake by arbuscular mycorrhizal maize and their dissipation in soil. Journal of Hazardous Materials 2011 187(1-3): 341-347.(IF 3.723 工程技术，一区）

Abstract

    Polycyclic aromatic hydrocarbons (PAHs) commonly found in soils can be degraded in rhizosphere but may also be taken up by plants. The effects of arbuscular mycorrhizal (AM) fungi on uptake of phenanthrene (PHE) and pyrene (PYR) in maize and on their dissipation in soil were investigated using the three-compartmentalized rhizoboxes. Inoculation of Glomus mosseae significantly (p < 0.01) increased PHE and PYR concentrations in maize roots and significantly (p < 0.05) enhanced PYR translocation from roots to stems in the soil treatments of the PHE + PYR spiked-soils added into the central compartment of the rhizoboxes. There was a significant (p < 0.05) dissipation gradient of PHE and PYR observed away from the maize roots with the highest dissipation rates recorded in rhizosphere zone in the central compartments of the rhizoboxes followed by near rhizosphere zone and bulk soil zone in the outer compartments. However G. mosseae only exerted minimal impacts on dissipation of PHE and PYR in the rhizosphere. The present study suggested that the hyphae and extraradical mycelium of AM fungi could play important roles in the uptake and translocation of PHE and PYR in plants. The present results indicated that there is a potential for the use of AM fungi and plant for remediating PAHs contaminated soils.

    2011年3月8日国家自然科学基金委亚洲处张永涛处长和日本科学技术振兴机构（Japan Science and Technology Agency—JST）Dr. Yasushi Ogasaka一行对我室进行了访问，并出席了JST项目交流会。

    我室蒋新研究员及四位NSFC(National Science Foundation of China)—JST项目负责人、三位MOST（Ministry of Science and Technology）—JST项目负责人以及主持过中日国际合作项目的多名研究员出席了会议。

    蒋新主持会议并向来宾简要介绍了研究所概况，张永涛和Dr. Yasushi Ogasaka分别介绍了国家基金委和日本科学技术振兴机构合作项目申请的具体情况。我室承担中日合作项目的施卫明、颜晓元研究员分别汇报了最新研究进 展，日方主管饶有兴趣地进行了提问，得到了满意的回答。此外，参会人员还就各自的研究领域和进展与两位客人进行了热烈的讨论。相信本次讨论将会推进我室中 日合作项目更加深入的研究和广泛交流。

Yan XY Cai ZC Wang SW et al.. Direct measurement of soil organic carbon content change in the croplands of China. Global Change Biology 2011 17(3): 1487-1496. (IF 6.346 环境科学，一区）

Abstract

    Agricultural soils in China have been estimated to have a large potential for carbon sequestration and modelling and literature survey studies have yielded contrasting results of soil organic carbon (SOC) stock change ranging from -2.0 to +0.6% yr-1. To assess the validity of earlier estimates we collected 1394 cropland soil profiles from all over the country and measured SOC contents in 2007-2008 and compared them with those of a previous national soil survey conducted in 1979-1982. The results showed that average SOC content in the 0-20 cm soil increased from 11.95 g kg-1 in 1979-1982 to 12.67 g kg-1 in 2007-2008 averaging 0.22% yr-1. The standard deviation of SOC contents decreased. Four major soil types had statistically significant changes in their mean SOC contents for 0-20 cm. These were: +7.5% for Anthrosols (paddy soils) +18.3% for Eutric Cambisols +30.5% for Fluvisols and -22.3% for Chernozems. The change of SOC contents showed a negative relationship with the average SOC contents of the two sampling campaigns only when soils in the region south of Yangtse River were excluded. SOC contents of the two major soil types in the region south of Yangtse River i.e. Haplic Alisols-Haplic Acrisols and Anthrosols (paddy soils) changed little or significantly increased though with a high SOC content. We suggest that the increase of SOC content is mainly attributed to the large increase in crop yields since the 1980s and the short history as cropland establishment is mainly responsible for the decrease in SOC content for some soil types and regions showing a SOC decline.

Wang P Kinraide TB Zhou DM et al.. Plasma Membrane Surface Potential: Dual Effects upon Ion Uptake and Toxicity. Plant Physiology 2011 155(2): 808-820. (IF 6.451 生物，二区Top）

Abstract

    Electrical properties of plasma membranes (PMs) partially controlled by the ionic composition of the exposure medium play significant roles in the distribution of ions at the exterior surface of PMs and in the transport of ions across PMs. The effects of coexisting cations (commonly Al³⁺ Ca²⁺ Mg²⁺ H⁺ and Na⁺) on the uptake and toxicity of these and other ions (such as Cu²⁺ Zn²⁺ Ni²⁺ Cd²⁺ and H₂AsO₄⁻) to plants were studied in terms of the electrical properties of PMs. Increased concentrations of cations or decreased pH in rooting media whether in solution culture or in soils reduced the negativity of the electrical potential at the PM exterior surface (ψ₀^o). This reduction decreased the activities of metal cations at the PM surface and increased the activities of anions such as H₂AsO₄⁻. Furthermore the reduced ψ₀^o negativity increased the surface-to-surface transmembrane potential difference thus increasing the electrical driving force for cation uptake and decreasing the driving force for anion uptake across PMs. Analysis of measured uptake and toxicity of ions using electrostatic models provides evidence that uptake and toxicity are functions of the dual effects of ψ₀^o (i.e. altered PM surface ion activity and surface-to-surface transmembrane potential difference gradient). This study provides novel insights into the mechanisms of plant-ion interactions and extends current theory to evaluate ion bioavailability and toxicity indicating its potential utility in risk assessment of metal(loid)s in natural waters and soils.

Dong HB Yao ZS Zheng XH et al.. Effect of ammonium-based non-sulfate fertilizers on CH(4) emissions from a paddy field with a typical Chinese water management regime. Atmospheric Environment 2011 45(5): 1095-11101. (IF 3.226 环境科学，二区Top）

Abstract

    The effects of ammonium-based non-sulfate fertilizers such as urea and-or ammonium phosphate (NH₄H₂PO₄) on methane (CH₄) emissions from paddy rice fields deserve attention as they are being used increasingly for rice cultivation. A four-year field campaign was conducted in the Yangtze River Delta from 2004 to 2007 to assess the effects of different application rates of urea plus NH₄H₂PO₄ on the CH₄ emissions from a paddy rice field. The experimental field was under a typical Chinese water regime that follows a flooding-midseason drainage-reflooding-moist irrigation mode. Over the course of four years the mean cumulative CH₄ emissions during the rice seasons were 221 136 and 112 kg C ha⁻¹ for nitrogen addition rates of 0 150 and 250 kg N ha⁻¹ respectively. Compared to the treatment without nitrogen amendments the 150 kg N ha⁻¹ decreased the CH₄ emissions by 6–59% (P < 0.01 in one year but not statistically significant in the others). When the addition rate was further increased to 250 kg N ha⁻¹ the CH₄ emissions were significantly reduced by 35–53% (P < 0.01) compared to the no-nitrogen treatment. Thus an addition rate of 250 kg N ha⁻¹ which has been commonly adopted in the delta region in the past two decades can be regarded as an effective management measure as regards increasing rice yields while reducing CH₄ emissions. Considering that doses of ammonium-based non-sulfate fertilizers higher than 250 kg N ha⁻¹ currently are and most likely will continue to be commonly applied for paddy rice cultivation in the Yangtze River Delta and other parts of China the inhibitory effects on CH₄ emissions from rice production are expected to be pronounced at the regional scale. However further studies are required to provide more concrete evidence about this issue. Moreover further research is needed to determine whether N management measures are also effective in view of net greenhouse gas fluxes (including CH₄ nitrous oxide ammonia emissions nitrate leaching and N loss from denitrification).

Zhang YP Wang F Wang CY et al.. Enhanced microbial degradation of humin-bound phenanthrene in a two-liquid-phase system. Journal of Hazardous Materials 2011 186(2-3): 1830-1836. (IF 3.723 工程技术，一区）

Abstract

    Humin the main component of soil organic matter greatly influences the nonlinear sorption and desorption hysteresis of polycyclic aromatic hydrocarbons (PAHs) in soil. However little is known about the bioavailability of PAHs bound to humin. In the present study a phenanthrene (PHE)-degrading bacterial strain – PHE9 – was isolated and identified as the genus Micrococcus. It was used to investigate the degradation of humin-bound PHE and PHE not bound to humin (non-humin PHE) in liquid mineral medium (MM) and in a two-liquid-phase system (TLPs). The results showed that in MM about 66.84% of humin-bound PHE was degraded after 49 days whereas almost all the non-humin PHE was degraded after 27 days. Compared to MM the TLPs showed a much better efficacy in the removal of PHE especially for humin-bound PHE: more than 97.28% of non-humin PHE was degraded in 11 days and over 85.62% of humin-bound PHE was degraded in 32 days. It could be concluded that most of humin-bound PHE could be degraded in the MM although humin decreased the bioavailability of PHE whereas the application of TLPs could enhance the biodegradation of humin-bound PHE.

Yuan JH Xu RK Zhang H. The forms of alkalis in the biochar produced from crop residues at different temperatures. Bioresource Technology 2011 102(3): 3488-3497. （IF 4.365 工程技术，一区）

Abstract

    The forms of alkalis of the biochars produced from the straws of canola corn soybean and peanut at different temperatures (300 500 and 700 degrees C) were studied by means of oxygen-limited pyrolysis. The alkalinity and pH of the biochars increased with increased pyrolysis temperature. The X-ray diffraction spectra and the content of carbonates of the biochars suggested that carbonates were the major alkaline components in the biochars generated at the high temperature; they were also responsible for the strong buffer plateau-regions on the acid-base titration curves at 500 and 700 degrees C. The data of FTIR-PAS and zeta potentials indicated that the functional groups such as -COO(-) (-COOH) and -O(-) (-OH) contained by the biochars contributed greatly to the alkalinity of the biochar samples tested especially for those generated at the lower temperature. These functional groups were also responsible for the negative charges of the biochars.

Wu YH Hu ZY Yang LZ et al.. The removal of nutrients from non-point source wastewater by a hybrid bioreactor. Bioresource Technology 2011 102(3): 2419-2426. （IF 4.365 工程技术，一区）

Abstract

    The aim of this project was to establish an economical and environmentally benign biotechnology for removing nutrients from non-point source wastewater. The proposal involves a hybrid bioreactor comprised of sequential anaerobic anoxic and aerobic (A(2)-O) processes and an eco-ditch being constructed and applied in a suburban area. Kunming south-western China where wastewater was discharged from an industrial park and suburban communities. The results show that the hybrid bioreactor fosters heterotrophic and autotrophic microorganisms. When the hydraulic load is 200 m(3) per day with the running mode in 12 h cycles the removal efficiencies of the nutrients were 81% for TP 74% for TDP 82% for TN 79% for NO(3)-N and 86% for NH(4)-N. The improved bacterial community structure and bacterial habitats further implied enhanced water quality and indicates that the easily-deployed affordable and environmentally-friendly hybrid bioreactor is a promising bio-measure for removing high loadings of nutrients from non-point source wastewater.

Zhang XX Wang S Wang Y et al.. Differential enantioselectivity of quizalofop ethyl and its acidic metabolite: Direct enantiomeric separation and assessment of multiple toxicological endpoints. Journal of Hazardous Materials 2011 186(1): 876-882. (IF 3.723 工程技术，一区）

Abstract

    Transformation products usually differ in environmental and toxicological properties compared to the parent contaminants thus causing potential and unknown environmental risks. To elucidate differential chiral recognition of the aryloxypropanoate herbicide quizalofop ethyl (QE) and its primary product (quizalofop acid QA) their enantiomeric separation and toxicological impacts to two freshwater algae were investigated. Addition of trace water (0.02–0.08% v-v) to the mobile phase selectively affected retention of analyte and induced simultaneous enantio-separation for the two compounds with intrinsical water-specific resolution mechanisms although they both possessed a chiral center in the 2-position of propionates. In algal suspensions QE was rapidly degraded to produce the acid metabolite (QA) and the product further declined whereas a reduction of QA as starting compound did not occur. Uptake and-or transformation of QE and QA were found a lack of enantioselectivity and isomer inversion while cellular membrane permeability membrane potential and algal growth showed enantioselectivity to different extents. These results suggested the presence of receptor chirality that was involved in the toxicological processes but invalid for uptake and transformation. Therefore quizalofop acid identified as environmentally relevant contaminant associated with application of the herbicide participated in the toxicological processes of the parent compound and exhibited distinct toxicological and chromatographic retention properties.