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Global leaf nitrogen and phosphorus stoichiometry and their scaling exponent

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National Science Review 2018年第5期5卷 728-739页

作者： Di Tian Zhengbing Yan Karl J.Niklas Wenxuan Han Jens Kattge Peter B.Reich Yongkai Luo Yahan Chen Zhiyao Tang Huifeng Hu Ian J.Wright Bernhard Schmid Jingyun Fang Institute of Ecology College of Urban and Environmental Sciencesand Key Laboratory for Earth Surface Processes of the Ministry of EducationPeking University Max-Planck-Institute for Biogeochemistry State Key Laboratory of Vegetation and environmental Change Institute of BotanyChinese Academy of Sciences College of Life sciences Capital Normal University Department of Plant biology Cornell University Department of Forest Resources University of Minnesota Department of Biological sciences Macquarie UniversitySydneyNSW 2109Australia10 Department of Evolutionary Biology and Environmental StudiesUniversity of Zurich Hawkesbury Institute for the Environment Western Sydney University Key Laboratory of Plant-Soil Interactions Ministry of EducationCollege of Resources and Environmental SciencesChina Agricultural University

Leaf nitrogen(N) and phosphorus(P) concentrations constrain photosynthetic and metabolic processes,growth and the productivity of plants. Their stoichiometry and scaling relationships regulate the allocation of N and P from subcellular to organism, and even ecosystem levels, and are crucial to the modelling of plant growth and nutrient cycles in terrestrial ecosystems. Prior work has revealed a general biogeographic pattern of leaf N and P stoichiometric relationships and shown that leaf N scales roughly as two-thirds the power of P. However, determining whether and how leaf N and P stoichiometries, especially their scaling exponents, change with functional groups and environmental conditions requires further verification. In this study, we compiled a global data set and documented the global leaf N and P concentrations and the N:P ratios by functional group, climate zone and continent. The global overall mean leaf N and P concentrations were 18.9 mg gand 1.2 mg g, respectively, with significantly higher concentrations in herbaceous than woody plants(21.72 mg gvs. 18.22 mg gfor N; and 1.64 mg gvs. 1.10 mg gfor P). Both leaf N and P showed higher concentrations at high latitudes than low latitudes. Among six continents, Europe had the highest N and P concentrations(20.79 and 1.54 mg g) and Oceania had the smallest values(10.01 and 0.46 mg g). These numerical values may be used as a basis for the comparison of other individual studies. Further, we found that the scaling exponent varied significantly across different functional groups,latitudinal zones, ecoregions and sites. The exponents of herbaceous and woody plants were 0.659 and0.705, respectively, with significant latitudinal patterns decreasing from tropical to temperate to boreal zones. At sites with a sample size ≥10, the values fluctuated from 0.366 to 1.928, with an average of *** factors including the intrinsic attributes of different life forms, P-related growth rates and relative nutrient availa

关键词： leaf nitrogen phosphorus stoichiometry scaling exponent functional group biogeography

Detection,isolation,and identification of cadmium-resistant bacteria based on PCR-DGGE

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Journal of environmental sciences 2007年第9期19卷 1114-1119页

作者： HU Qing DOU Min-na QI Hong-yan XIE Xiang-ming ZHUANG Guo-qiang YANG Min Department of environmental Biotechnology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China. biology Science and Technology College Beijing Forestry University Beijing 100083 China

This study focused on the screening of cadmium-resistant bacterial strains from Pb-Zn tailing. We investigated the diversity of microbial community inhabiting Dong-san-cha Pb-Zn tailing in Beijing, China, by polymerase chain reaction-denaturing gradient gel electrophoresis （DGGE） of 16S rRNA gene of bacterial strain, and found two dominant strains in the DGGE profile. Using special culture media, we isolated two strong cadmium-resistant bacterial strains. On the basis of morphological, physiological, and biochemical characteristics, BIOLOG, and 16S rDNA sequencing, the two strains were identified as Bacillus cereus and Enterobacter cloacae. Minimal inhibitory concentrations （MICs） of heavy metals for the bacteria were determined. E. cloacae showed higher MIC values for heavy metals and a larger range of antibiotic resistance than B. cereus.

关键词： Bacillus cereus Enterobacter cloacae PCR-DGGE cadmium resistance antibiotic resistance

Protecting wild yak (Bos mutus) species and preventing its hybrid in China

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Journal of Arid Land 2016年第5期8卷 811-814页

作者： WANG Shengli NAN Zhongren Daniel PRETE Gansu Key Laboratory for environmental Pollution Prediction and Control College of Earth and Environmental SciencesLanzhou University Department of Chemistry and biology Ryerson University

China has made efforts to protect wild yak （Bos mutus） species and prevent the hybrids between wild yak and domestic yak （Bos grunniens） *** present,wild yak population of a reasonable estimate would be over 70,*** to conservation efforts in environmental protection and ecological construction such as the Wildlife Protection and Nature Reserve Construction Project,the ＂Grain-for-Green＂ Project and the Natural Forest Resources Protection Project,the number of wild yaks is *** general,Tibetan Plateau＇s ecosystem is getting better and its environmental quality shows a gradual improving *** Plateau is one of the world＇s cleanest regions called as the ＂Third Pole＂.In order to preserve the genetic pool of wild yaks,local pastoralists and polices drive off the wild male yaks from the domestic yak herds by making noise （banging washbasins,pots,etc.） or driving *** government also incentivizes the culling of domestic yaks found in wild *** the sake of the biological and genetic features of this wild species,and the pastoralist way of life,wild yaks should continuously be protected to keep their genetic *** appeal plans to investigate the gene pollution of wild yaks in some important distribution regions of this *** the face of hybridizing with domestic yaks,proper guidance is urgently needed to address genetic pollution and protect the genetic integrity of wild yaks.

关键词： wild and domestic yaks habitat competition genetic integrity genetic pollution pastoralists migration Altun Mountain National Nature Reserve Tibetan Plateau

Effects of cowpea(Vigna unguiculata) root mucilage on microbial community response and capacity for phenanthrene remediation

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Journal of environmental sciences 2015年第7期27卷 45-59页

作者： Ran Sun Richard W.Belcher Jianqiang Liang Li Wang Brian Thater David E.Crowley Gehong Wei State Key Laboratory of Crop Stress biology in Arid Areas College of Life Sciences Northwest A&F University Department of environmental sciences University of California at Riverside

Biodegradation of polycyclic aromatic hydrocarbons（PAHs） is normally limited by their low solubility and poor bioavailability. Prior research suggests that biosurfactants are synthesized as intermediates during the production of mucilage at the root tip. To date the effects of mucilage on PAH degradation and microbial community response have not been directly examined. To address this question, our research compared 3 cowpea breeding lines（Vigna unguiculata） that differed in mucilage production for their effects on phenanthrene（PHE） degradation in soil. The High Performance Liquid Chromatography results indicated that the highest PHE degradation rate was achieved in soils planted with mucilage producing cowpea line C1, inoculated with Bradyrhizobium, leading to 91.6% PHE disappearance in 5 weeks. In root printing tests, strings treated with mucilage and bacteria produced larger clearing zones than those produced on mucilage treated strings with no bacteria or bacteria inoculated strings. Experiments with14C-PHE and purified mucilage in soil slurry confirmed that the root mucilage significantly enhanced PHE mineralization（82.7%）, which is 12% more than the control treatment without mucilage. The profiles of the PHE degraders generated by Denaturing gradient gel electrophoresis suggested that cowpea C1, producing a high amount of root mucilage, selectively enriched the PHE degrading bacteria population in rhizosphere. These findings indicate that root mucilage may play a significant role in enhancing PHE degradation and suggests that differences in mucilage production may be an important criterion for selection of the best plant species for use in phytoremediation of PAH contaminated soils.

关键词： Bioremediation Mucilage Phytoremediation PAH mineralization Rhizosphere

Effects of light and salinity on carotenoid biosynthesis in Ulva prolifera

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Acta Oceanologica Sinica 2020年第10期39卷 50-57页

作者： Yuan He Yuantu Ye Songdong Shen College of biology and Basic medical sciences Soochow UniversitySuzhou 215123China

Ulva prolifera is a green alga that plays an important role in green *** biosynthesis is a basic terpenoid metabolism that is very important for maintaining normal life activities in *** this study,we first reported the complete sequences of all genes in the 2-C-methyl-D-erythritol 4-phosphate(MEP)pathway,which is the only carotenoid synthesis pathway in ***,we compared these genes with those of other ***,by detecting the carotenoid contents and expression levels of key genes participating in carotenoid biosynthesis in *** under three different light(1000 lx,5000 lx and 12000 lx)and salinity(12,24 and 40)regimes,we found that carotenoid synthesis could be influenced by light and salinity,such that low light and high salinity could promote the synthesis of *** results showed that the expression levels of genes involved in the MEP and the downstream pathway could affect the biosynthesis of carotenoids at the molecular *** study contributes to a better understanding of the roles of genes participating in carotenoid biosynthesis in *** and the environmental regulation of these genes.

关键词： U.prolifera carotenoid MEP pathway light salinity

Effects of O3/Cl2 disinfection on corrosion and opportunistic pathogens growth in drinking water distribution systems

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Journal of environmental sciences 2018年第11期30卷 38-46页

作者： Haibo Wang Chun Hu Suona Zhang Lizhong Liu Xueci Xing Key Laboratory of Drinking Water Science and Technology Research Center for Eco-Environmental Sciences Chinese Academy of SciencesBeijing 100085 China Research Institute of environmental studies at Greater Bay School of Environmental Sciences and Engineering Guangzhou University Guangzhou 510006 China university of Chinese Academy of sciences Beijing 100049 China

The effects of O3/Cl2 disinfection on corrosion and the growth of opportunistic pathogens in drinking water distribution systems were studied using annular reactors （ARs）. The corrosion process and most probable number （MPN） analysis indicated that the higher content of iron-oxidizing bacteria and iron-reducing bacteria in biofilms of the AR treated with O3/Cl2 induced higher Fe304 formation in corrosion scales. These corrosion scales became more stable than the ones that formed in the AR treated with Cl2 alone. O3/Cl2 disinfection inhibited corrosion and iron release efficiently by changing the content of corrosion-related bacteria. Moreover, ozone disinfection inactivated or damaged the opportunistic pathogens due to its strong oxidizing properties. The damaged bacteria resulting from initial ozone treatment were inactivated by the subsequent chlorine disinfection. Compared with the AR treated with Cl2 alone, the opportunistic pathogens M. auium and L. pneumophila were not detectable in effluents of the AR treated with O3/Cl2, and decreased to （4.60 ± 0.14） and （3.09 ± 0.12） loglo （gene copies/g corrosion scales） in biofilms, respectively. The amoeba counts were also lower in the AR treated with O3/Cl2. Therefore, O3/Cl2 disinfection can effectively control opportunistic pathogens in effluents and biofilms of an AR used as a model for a drinking water distribution system.

关键词： Ozone Chlorine Corrosion Opportunistic pathogens Drinking water distribution systems

Biodegradation of aniline by Candida tropicalis AN1 isolated from aerobic granular sludge

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Journal of environmental sciences 2011年第12期23卷 2063-2068页

作者： Dianzhan Wang Guanyu Zheng Shimei Wang Dewei Zhang Lixiang Zhou Department of environmental Engineering College of Resources and Environmental Sciences Nanjing Agricultural University Nanjing 210095 China Department of biology Hong Kong Baptist University Hong Kong 999077 China

Aniline-degrading microbes were cultivated and acclimated with the initial activated sludge collected from a chemical wastewater treatment plant. During the acclimation processes, aerobic granular sludge being able to effectively degrade aniline was successfully formed, from which a preponderant bacterial strain was isolated and named as AN1. Effects of factors including pH, temperature, and second carbon/nitrogen source on the biodegradation of aniline were investigated. Results showed that the optimal conditions for the biodegradation of aniline by the strain AN1 were at pH 7.0 and 28–35°C. At the optimal pH and temperature, the biodegradation rate of aniline could reach as high as 17.8 mg/（L·hr） when the initial aniline concentration was 400 mg/L. Further studies revealed that the addition of 1 g/L glucose or ammonium chloride as a second carbon or nitrogen source could slightly enhance the biodegradation efficiency from 93.0% to 95.1%–98.5%. However, even more addition of glucose or ammonium could not further enhance the biodegradation process but delayed the biodegradation of aniline by the strain AN1. Based on morphological and physiological characteristics as well as the phylogenetic analysis of 26S rDNA sequences, the strain AN1 was identified as Candida tropicalis.

关键词： aniline aerobic granular sludge biodegradation Candida tropicalis AN1

Stormwater runoff pollution loads from an urban catchment with rainy climate in China

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Frontiers of environmental Science & Engineering 2012年第5期6卷 672-677页

作者： Liqing LI Baoqing SHAN Chenqing YIN School of environmental studies China University of GeosciencesWuhan 430074China SKLAC Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China

An older urban district in Wuhan, China, is transitioning from discharging sewage and stormwater directly into lakes, to directing the sewage to wastewater treatment plants （WWTPs）. Dealing with polluted storm- water discharge is a great challenge. Stormwater runoff from an urban catchment with a combined sewer system was sampled and analyzed over a three-year period. Results indicate that wet weather flows account for 66%, 31%, 17%, and 13 % of the total load of suspended solids （SS）, chemical oxygen demand （COD）, total nitrogen, and total phosphorus, respectively. The first flush of COD and SS was significant in all runoff events. More than 50% of the SS and COD loads were transported by the first 30% of runoff volume. Storage and treatment of the first 10 mm from each combined sewer overflow event could reduce more than 70% of the annual COD overflow load. An integrated solution is recommended, consisting of a tank connected to the WWTP and a detention pond, to store and treat the combined sewer overflow （CSO）. These results may be helpful in mitigating CSO pollution for many other urban areas in China and other developing countries.

关键词： combined sewer overflow pollution load firstflush detention basins

Variations between rice cultivars in iron and manganese plaque on roots and the relation with plant cadmium uptake

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Journal of environmental sciences 2010年第7期22卷 1067-1072页

作者： Jianguo Liu Changxun Cao Minghung Wong Zhijun Zhang Yuhong Chai School of environmental and Safety Engineering Jiangsu Polytechnic University Changzhou 213164 China Croucher Institute for environmental sciences and Department of biology Hong Kong Baptist University Hong Kong China

To understand certain mechanisms causing variations between rice cultivars with regard to cadmium uptake and tolerance, pot soil experiments were conducted with two rice cultivars of different genotypes under different soil Cd levels. The relationships between plant Cd uptake and iron/manganese （Fe/Mn） plaque formation on roots were investigated. The results showed that rice cultivars differed markedly in Cd uptake and tolerance. Under soil Cd treatments, Cd concentrations and accumulations in the cultivar Shanyou 63 （the genotype indica） were significantly higher than those in the cultivar Wuyunjing 7 （the genotype japonica）（P 〈 0.01, or P 〈 0.05）, and Shanyou 63 was more sensitive to Cd toxicity than Wuyunjing 7. The differences between the rice cultivars were the largest at relatively low soil Cd level （i.e., 10 mg/kg）. Fe concentrations in dithionite-citrate-bicarbonate root extracts of Shanyou 63 were generally lower than that of Wuyunjing 7, and the difference was the most significant under the treatment of 10 mg Cd/kg soil. The results indicated that the formation of iron plaque on rice roots could act as a barrier to soil Cd toxicity, and may be a ＂buffer＂ or a ＂reservoir＂ which could reduce Cd uptake into rice roots. And the plaque may contribute, to some extent, to the genotypic differences of rice cultivars in Cd uptake and tolerance.

关键词： rice (Orvza sativa L.) cadmium zenotype iron/manganese plaque