花生不同品种植株重金属As和Hg的富集与转运规律

在大田生产条件下,以8个主栽花生品种为试材对花生植株不同器官中重金属As和Hg元素的吸收、富集与转运规律进行了研究。结果表明,供试的花生品种植株根系、茎叶中As和Hg含量存在显著性差异,籽仁中As含量和果壳中Hg含量存在显著性差异,而果壳中As和籽仁中Hg含量差异不显著。花生植株根系As含量最高,其次为茎叶和果壳,籽仁中的含量最低;花生植株根系Hg含量最高,其次为果壳和茎叶,籽仁中的含量最低。不同花生品种植株根系、茎叶、籽仁和果壳中As和Hg的富集量均存在显著性差异,植株中的As和Hg主要富集于茎叶中,其次为果壳,根系和籽仁中富集量较低。不同花生品种茎叶和籽仁中的As转运量系数差异显著,果壳中的差异不显著;花生根系吸收的As转运到茎叶中最多,其次为果壳中,转运到籽仁中最少。不同花生品种茎叶、籽仁和果壳中的Hg转运量系数均呈现显著性差异,花生根系吸收的Hg主要转运到植株茎叶中,籽仁和果壳中很少。花生对As和Hg的富集量和转运能力差异是造成花生籽仁含量高低的主要原因。     

Advances in experimental research in HCV cell model and anti-HCV effect of As2O3

Hepatitis C virus (HCV) is a human pathogen responsible for liver diseases including acute and chronic hepatitis and hepatocellular carcinoma. However, the high prevalence, the absence of antiviral drugs and vaccines for prevention and treatment are the difficult medical problems. Lacking appropriate culture method and small animal model have severely limited investigation of the HCV infection mechanism and the development of the therapeutic strategy. Recently, the in vitro culture system develops rapidly, and provides a powerful tool for HCV related research. Despite the well known toxicity of the chemical, arsenic trioxide (As₂O₃) is effective for treating the patients with refractory or relapsed acute promyelocytic leukemia and many other cancers. Interestingly, As₂O₃ shows the ability of inhibiting HCV RNA replication and infection. This review describes the different types of in vitro HCV models developed, and many studies of the potent effect of As₂O₃ against HCV and its associated molecular mechanisms.     

河口湿地土壤砷吸附-解吸特性的研究

该试验研究了湿地土壤砷的吸附-解吸特性。结果表明:3个湿地土样对砷的吸附均随平衡液中砷浓度的增加而增大,且均可用Langmuir方程和Freundlich方程来描述,相关系数均大于0.9,达极显著水平。用Freundlich求得的湿地土壤对砷的吸附作用力强度以及由Lang-muir方程最大缓冲容量以及最大吸附量的大小顺序为土样2土样3土样1。湿地土壤对砷的解吸量随其吸附量的增加而增加。     

一次性消解连续测定食品中砷、硒和汞的研究

研究了一次性消解样品用HG-AFS法连续测定食品中砷、硒和汞3种元素的新方法。在选定的试验条件下测得Se、As、Hg的RSD分别为：3.7%,2.8%,和4.7%;回收率分别为：95.0%、102.0%和91.9%;该法具有快速、简单、准确性好,和国标法分别消解样品相比,有一次性消解样品,可连续完成测定3种元素含量,操作简单,快速,节省试剂,工作效率高等优点,值得推广应用。     

芦苇对砷污染土壤中砷的吸收特征研究

以芦苇为材料,对含砷土壤中砷的吸收转运情况进行分析研究,以期为利用芦苇修复本地砷污染土壤提供科学依据。通过盆栽模拟试验,添加外源砷,设置6 个不同的土壤砷浓度,以芦苇为砷污染土壤修复材料,生长60 天后,对芦苇在砷污染土壤环境中的生长、吸收及转运规律进行研究和探索。结果表明：芦苇经不同砷浓度胁迫60 天后,不同砷浓度对芦苇株高、萌芽及展叶均有一定影响,砷浓度从200 mg/kg 梯度依次加大时,芦苇地上地下部分鲜重呈现较快下降的趋势,芦苇干重随着土壤砷浓度的增加总体呈现下降的趋势,土壤砷含量与芦苇地下部分砷含量呈极显著的正相关。可得出结论：芦苇是一种耐砷性强的植物,具有修复当地砷污染土壤的潜能。     

三种铁氧化物对As(Ⅲ)和As(Ⅴ)的吸附研究

采用批量吸附试验,研究实验室制备的水铁矿、磁铁矿和纤铁矿对As(Ⅲ)和As(Ⅴ)的吸附性能。结果表明,在p H中性条件下,结晶差的水铁矿吸附砷的能力明显优于结晶较好的磁铁矿和纤铁矿,准二级动力学方程拟合效果较好,说明存在多种吸附过程,并可能涉及专性吸附作用;在酸性条件下,三种铁氧化物对As(Ⅲ)和As(Ⅴ)的吸附能力大小顺序均为水铁矿磁铁矿纤铁矿,铁氧化物吸附As(Ⅴ)的能力优于As(Ⅲ),Langmiur方程和Freundlich方程拟合效果均较好,说明铁氧化物对砷的吸附为均匀介质表面的单层吸附或非均匀介质表面的多层吸附;在弱酸至弱碱范围内,三种铁氧化物对As(Ⅲ)的吸附效果均较好且吸附量变化不大,强酸和强碱条件都会引起铁氧化物吸附As(Ⅲ)量的降低,三种铁氧化物对As(Ⅴ)的吸附均随着p H升高而逐渐减少;由于竞争吸附作用,磷酸盐浓度的增加使三种铁氧化物对As(Ⅲ)和As(Ⅴ)的吸附显著减少;随着腐殖酸浓度的增加,三种铁氧化物对As(Ⅲ)的吸附能力逐渐减小,低浓度的腐殖酸微弱地促进铁氧化物对As(Ⅴ)的吸附,高浓度的腐殖酸抑制As(Ⅴ)的吸附。     

石墨炉原子吸收法测定大米中的砷

采用微波消解法进行样品前处理,研究了石墨炉吸收法测定大米中的As。结果表明,该研究消除了基体的干扰,选择了适宜的石墨炉升温程序,检出限可达1.2 ng/mL,检测范围为4～50 ng/mL,标准加样回收率为95.0%～106.7%,As含量为1.02μg/g,RSD为1.7%。     

As对谷子萌发、幼苗生长及抗氧化酶系统的影响

为探究As对谷子苗期生长的影响及谷子生长的临界浓度,设置As浓度梯度分别为0,2,4,8,10mg/kg,以石英砂为基质,通过培养试验,分析探讨不同浓度As对谷子萌发、苗期生长与抗氧化酶系统的影响。研究表明:低浓度的As(4mg/kg)促进谷子萌发,高浓度的As(≥4mg/kg)抑制谷子萌发。当As浓度为2 mg/kg时,谷子的发芽势、发芽率和发芽指数在所有处理中最高,其值分别为18.67%,32.00%和19.00%。低浓度的As对谷子幼苗生长有促进作用,高浓度对其有抑制作用,当As浓度为2mg/kg,谷子的株高、根长和地上部鲜重与地下部鲜重都达到最大值,分别为15.46,7.34cm和0.64,0.16g,随着As浓度梯度增加,地下部鲜重/地上部鲜重先增加后降低,As对根系的促进与抑制作用大于地上部,谷子幼苗根部的As含量均明显高于地上部,且TF值逐渐减小;当As浓度4mg/kg时,As能促进谷子叶绿素的合成,在As浓度为2 mg/kg时,谷子的叶绿素a、叶绿素b和叶绿素总量显著高于对照28.38%,51.60%,37.06%,As浓度高于4mg/kg时,谷子的叶绿素合成受到抑制;随着As浓度梯度的增加,谷子幼苗的SOD活性不断增强,POD与CAT活性呈先增加后减小的趋势,但均高于对照,As浓度4mg/kg后,CAT活性开始减小;As浓度8mg/kg后,谷子幼苗的POD活性开始减小,表明低浓度的As(4mg/kg)对谷子萌发及幼苗生长有促进作用,高浓度的As(≥4mg/kg)抑制谷子萌发和幼苗生长,且根系对As胁迫的反应更为敏感,抗氧化酶系统(POD和CAT)活性降低。研究可为谷子的抗污染栽培和无公害生产提供科学依据。     

Arsenic contamination in cropping systems under varying irrigation sources in the deltaic plain of India

A field experiment was conducted in an arsenic endemic area of West Bengal, India (22°57?N, 89°33?E) in 2010–2012 to understand different prevalent cropping systems of the area as to nature of arsenic uptake by the crops and influence of different sources of irrigation water. The experiment was laid out in split plot design consisting two irrigation managements [I₁: irrigation with shallow tube well (STW) and I₂: irrigation from harvested pond water (PW)] in main plot and four cropping systems in sub plot were C₁: pea- summer rice- cowpea, C₂: potato- green gram- elephant foot yam (EFY), C₃: wheat- jute- winter rice and C₄: French bean- sesame- winter rice. Irrigation from PW recorded less arsenic uptake compared to STW. Arsenic uptake was minimum with French bean- sesame- winter rice (C₄), followed by potato – green gram – EFY (C₂). System equivalent yield was the highest with C₂. The highest return was recorded with C₂ and the return per dollar (USD) investment was the maximum with C₁, followed by C₂. Potato- green gram- EFY (C₂) proved to be the better option for the farmers in arsenic contaminated area with greater yield potential, highest return per dollar investment and less arsenic uptake.     

Arsenic Bioremediation Potential of Arsenite-Oxidizing Micrococcus sp. KUMAs15 Isolated from Contaminated Soil

Environmental arsenic (As) contamination, considered as the largest mass poisoning of the human population, has become a serious health concern for the people of South East Asia, including those living in the Bengal delta. An As-resistant strain, KUMAs15, was isolated from the As-contaminated fields in Nadia Ddistrict in West Bengal, India and was evaluated for its possible use in environmental As bioremediation. Molecular identification based on 16S rDNA gene sequencing revealed that the strain belonged to the genus Micrococcus. The strain tolerated high levels of As and oxidized arsenite under the culture condition. The strain also accumulated large quantities of As when exposed to a wide range of environmentally relevant concentrations of inorganic As. Analysis of the aoxB, arsB, and arsC gene expression explained the underlying cause of arsenite oxidation and As accumulation by KUMAs15. The As-resistant strain KUMAs15 of Micrococcus sp. was suggested to be a potential environmental As decontaminant.