小麦生长周期中土壤Cu的迁移转化实验研究

通过盆栽试验,研究了不同土壤Cu添加浓度下,在小麦生长不同时期,小麦根区土壤与非根区土壤中总量Cu和有效态Cu的浓度,以此揭示其迁移转化特征。研究发现:小麦生长可以对土壤中的Cu进行吸收,拔节期小麦吸收能力最强;Cu添加有利于小麦对土壤中Cu的吸收,在试验水平下,添加浓度越高促进作用越明显,在200 mg/kg Cu添加浓度下,成熟期土壤中Cu含量较幼苗期减少了79%;小麦生长使土壤中有效态Cu占总量Cu的比重增加,并且使非根区土壤中Cu向根区土壤迁移。     

活性污泥储存与消耗乙酸基质的试验研究与模拟

同时贮存与生长理论认为,活性污泥吸收有机碳基质同时用于储存和生长.向SBR反应器投加不同浓度乙酸基质,监测活性污泥氧利用速率(OUR)、聚羟基烷酸盐(PHA)和出水COD的变化,运用活性污泥同时贮存与生长理论分析有机碳储存与消耗过程的特征.结果表明,饱食期结束与COD消耗至最低水平、PHA浓度出现最大值和OUR由最大值急速下降相对应;在饱食阶段,基质贮存OUR是利用外部基质直接生长OUR的2倍.随基质投加历时延长,饱食期平均OUR和最大OUR均下降,PHA产率降低,甚至出现PHA净消耗.因此,基质投加方式对有机碳基质储存与消耗有重要影响.     

农业文化遗产地有机生产转换期农产品价格补偿测算——以云南省红河县哈尼梯田稻作系统为例

高效农业技术广泛使用提高了农业生产效率,促进了粮食产量增长,但同时也带来环境问题、食品安全问题和传统农业文化逐渐消失等负面效应。哈尼梯田作为全球重要农业文化遗产(GIAHS),具有生态价值、农业生产价值和景观价值等多重价值,保护哈尼梯田农业系统意义重大。通过有机生产提高稻谷价格的方式,推动农民继续种植水稻,可以达到保护哈尼梯田农业系统的目的。然而,从非有机到有机生产有一个转换期,这期间稻谷无法以有机产品的价格出售,所以,政府须给予一定的价格补偿才可保证农民利益和生产的持续性。论文采用问卷和访谈等调查方法,获取哈尼梯田地区农户有机转换期种植投入产出状况和劳动力外出务工收入状况,以及现代规模生产方式下的投入产出状况,通过分析对比和核算,得到结果如下:1哈尼梯田地区有机转换期水稻种植直接投入高于现代水稻种植方式,总投入成本中劳动力成本占比最大,而单产低于现代水稻种植方式;2哈尼梯田地区的青壮年劳动力偏向于在城市生活和务工,外出务工收入明显高于常规农业收入,使农业机会成本较高;3有机转换期的稻谷价格补偿至少2.84元/kg才可保证有机转换期农民收入稳定,从而达到保护哈尼梯田景观的目的。     

季节性温度升高对落干期消落带土壤氮矿化影响

为揭示季节性温度升高对消落带落干期土壤氮矿化的影响,分别采集三峡支流澎溪河消落带上游和下游两个水文断面,155 m(低)、165 m(中)和175 m(高)这3个水位高程表层土壤,结合落干期气温变化特点,在25℃和35℃两个温度下进行恒温培养.结果表明,消落带土壤总氮和硝态氮在上游断面和高水位高程含量更高,而下游和低水位高程含量更低,铵态氮分布与其相反.硝态氮是无机氮的主要存在形式,占无机氮的57.4%~84.7%.相同培养温度下,氨化、硝化、净氮矿化速率均表现为随水位高程增加,随流域断面由下至上而显著增加(P0.05);总体上,在水位高程和流域断面上均表现为:温度升高使硝化速率和净氮矿化速率显著增加(P0.05),而对土壤氨化速率无显著影响(P0.05).     

Concentrations of Heavy Metals in Muscle with Relation to the Growth of Two Marine Fish Species

Heavy metal concentrations in muscle and their relation to thegrowth of two marine fish species,including tonguefish( Cynoglossus arel) and mullet( Mugil cephalus),were studied. The samples were collected in Bach Dang estuary andconcentrations of heavy metals( As,Cd,Co,Mn,Cu,Zn,Pb,and V) in muscle of the fisheswere determined. The result showed that the accumulated trend of heavy metal is different between fish species. The concentration of As,Zn,Mn,V,Cu,Pb,Co and Cd in tonguefish were 73. 7 ± 30. 6,22. 82 ± 4.87,3. 44 ± 2. 13,1. 61 ± 0. 15,0. 71 ± 0. 13,0. 45 ± 0. 24,0. 03 ± 0. 02 and 0. 02 ± 0. 02 mg·g-1,respectively. Meanwhile the concentration of Zn,As,V,Mn,Cu,Pb,Co and Cd in mullet were 83. 41 ±19. 68,9. 78 ± 1. 92,1. 36 ± 0. 54,1. 29 ± 0. 51,0. 65 ± 0. 12,0. 42 ± 0. 20,0. 06 ± 0. 03 and0. 03 ± 0. 01mg·g-1,respectively. Comparison of metal levels among thesespecies indicated that the concentrations of As and Mn in tonguefish were significantly higher than those in mullet,whereas Zn levels in mullet were found to be higher than that in tonguefish. There is no significant differences of Cd,Co,Cu,Pb and V levels in muscle between two species. Significant inversed relationshipsbetween concentration levels of metals and lengths of tonguefish were found for Mn,Cu and Zn,butnot for As,Cd,Pb,and V. There were no significant relationships between the heavy metal concentrations and the length of mullet. In general,decreasesof the heavy metal concentrations corresponded to the increases of fish body lengths,particularly for As,Co,Cu,Mn and V and the exception for Cd. Terefore reduced risks were associated with consuming biggermullet fish,and increased risks of As and Cd were associated with consuming bigger tonguefish in Bach Dang river mouth.     

5氟尿嘧啶对蛋白核小球藻和羊角月芽藻生长及叶绿素含量的影响

近年来,抗癌药的环境污染特征及其生态风险引起了广泛关注。为获取典型抗癌药5氟尿嘧啶的基础生态毒性数据,以蛋白核小球藻(Chlorella pyrenoidosa)和羊角月芽藻(Selenastrum capricornutum)为受试生物,考察了5氟尿嘧啶对2种绿藻的生长和叶绿素含量的影响。结果表明,5氟尿嘧啶对蛋白核小球藻和羊角月芽藻的生长具有抑制作用,随着暴露浓度升高,细胞生长抑制率增强。5氟尿嘧啶对2种绿藻的96 h半数抑制浓度(EC50)分别为450.36 mg·L~(-1)和692.30 mg·L~(-1),属于低毒性物质。暴露96 h后,低浓度5氟尿嘧啶(32 mg·L~(-1))对蛋白核小球藻和羊角月芽藻叶绿素含量有一定的促进作用,高浓度5氟尿嘧啶(32~500 mg·L~(-1))则抑制了2种绿藻的叶绿素含量,且两者具有明显的负相关关系。和叶绿素b相比,叶绿素a对5氟尿嘧啶胁迫更为敏感。     

Dynamics of bacterial community of Suillus granulatus mushroom shiro in Pine (Pinus tabuliformis) forests北大核心CSCD

To evaluate bacterial community variation in the mushroom shiro of Suillus granulatus during fruiting, we collected soil samples from the mushroom shiro in the pine (Pinus tabuliformis) forest of mountainous area in Beijing from May to November and evaluated the bacterial community using polymerase chain reaction - denaturing gradient gel electrophoresis (PCR-DGGE). Total soil DNA was extracted using a commercial soil DNA isolation kit. PCR amplification and DGGE were performed using bacterial universal primers 338F and 518R. The specific bands were excised from the gel and sequenced. The results revealed that soil bacterial community maintained considerably high level and changed seasonally with the mushroom fruiting. In total, 53 bands of DGGE profiles were sequenced and divided into 5 phyla (Acidobacteria, Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria and 22 genera (Acidobacterium, Aminobacter, et al). Species from Proteobacteria and Acidobacteria were the dominant bacterial groups sharing considerably high relative abundance, while class a-Proteobacteria was the most abundant group. The variation of the relative abundance of γ-Proteobacteria species was consistent with the mushroom fruiting season. The relative abundance of Acidobacteria species obviously increased before mushroom flush (in July). The fruiting of S. granulatus and the relative abundance of γ-Proteobacteria were correlated with each other. The present study provided a basis for conservation and domestication of mushroom S. granulatus.     

Effects of two polybrominated diphenyl ethers (BDE-47, BDE-209) on the swimming behavior,population growth and reproduction of the rotifer Brachionus plicatilis

Polybrominated diphenyl ethers(PBDEs) are new kinds of persistent organic pollutants(POPs) and their potential threats to the equilibrium and sustainability of marine ecosystems have raised worldwide concerns. Here, two kinds of PBDEs, tetra-BDE(BDE-47)and deca-BDE(BDE-209) were applied, and their toxic effects on the swimming behavior,population growth and reproduction of Brachionus plicatilis were investigated. The results showed that:(1) The actual concentrations of BDE-47 and-209 in the seawater phase measured by GC–MS(Gas Chromatography-Mass Spectrometer) were much lower than their nominal concentrations.(2) In accordance with the 24-hr acute tests, BDE-209 did not show any obvious swimming inhibition to rotifers, but a good correlation did exist between the swimming inhibition rate and BDE-47 concentration suggesting that BDE-47 is more toxic than BDE-209.(3) Both BDE-47 and-209 had a significant influence on the population growth and reproduction parameters of B. plicatilis including the population growth rate, the ratio of ovigerous females/non-ovigerous females(OF/NOF), the ratio of mictic females/amictic females(MF/AF), resting egg production and the mictic rate, which indicate that these parameters in B. plicatilis population were suitable for monitoring and assessing PBDEs. Our results suggest that BDE-47 and-209 are not acute lethal toxicants and may pose a low risk to marine rotifers at environmental concentrations for short-term exposure. They also accumulate differently into rotifers. Further research data are needed to understand the mechanisms responsible for the effects caused by PBDEs and to assess their risks accurately.     

Genomic analyses of metal resistance genes in three plant growth promoting bacteria of legume plants in Northwest mine tailings, China

To better understand the diversity of metal resistance genetic determinant from microbes that survived atmetal tailings in northwest of China, a highly elevated level of heavymetal containing region, genomic analyses was conducted using genome sequence of three native metal-resistant plant growth promoting bacteria (PGPB). It shows that: Mesorhizobium amorphae CCNWGS0123 contains metal transporters from P-type ATPase, CDF (Cation Diffusion Facilitator), HupE/UreJ and CHR (chromate ion transporter) family involved in copper, zinc, nickel as well as chromate resistance and homeostasis. Meanwhile, the putative CopA/CueO system is expected to mediate copper resistance in Sinorhizobium meliloti CCNWSX0020 while ZntA transporter, assisted with putative CzcD, determines zinc tolerance in Agrobacterium tumefaciens CCNWGS0286. The greenhouse experiment provides the consistent evidence of the plant growth promoting effects of these microbes on their hosts by nitrogen fixation and/or indoleacetic acid (IAA) secretion, indicating a potential in-site phytoremediation usage in themining tailing regions of China.     

Effects of two polybrominated diphenyl ethers (BDE-47, BDE-209) on the swimming behavior, population growth and reproduction of the rotifer Brachionus plicatilis

Polybrominated diphenyl ethers (PBDEs) are new kinds of persistent organic pollutants (POPs) and their potential threats to the equilibrium and sustainability of marine ecosystems have raised worldwide concerns. Here, two kinds of PBDEs, tetra-BDE (BDE-47) and deca-BDE (BDE-209) were applied, and their toxic effects on the swimming behavior, population growth and reproduction of Brachionus plicatilis were investigated. The results showed that: (1) The actual concentrations of BDE-47 and -209 in the seawater phase measured by GC-MS (Gas Chromatography-Mass Spectrometer) were much lower than their nominal concentrations. (2) In accordance with the 24-hr acute tests, BDE-209 did not show any obvious swimming inhibition to rotifers, but a good correlation did exist between the swimming inhibition rate and BDE-47 concentration suggesting that BDE-47 ismore toxic than BDE-209. (3) Both BDE-47 and -209 had a significant influence on the population growth and reproduction parameters of B. plicatilis including the population growth rate, the ratio of ovigerous females/non-ovigerous females (OF/NOF), the ratio of mictic females/amictic females (MF/AF), resting egg production and the mictic rate, which indicate that these parameters in B. plicatilis population were suitable for monitoring and assessing PBDEs. Our results suggest that BDE-47 and -209 are not acute lethal toxicants and may pose a low risk to marine rotifers at environmental concentrations for short-term exposure. They also accumulate differently into rotifers. Further research data are needed to understand the mechanisms responsible for the effects caused by PBDEs and to assess their risks accurately.