壳寡糖缓解小麦镉毒害的某些生理特性研究

利用不同浓度壳寡糖溶液对小麦种子浸种,种子萌发后,对小麦幼苗进行Cd胁迫,研究了不同浓度的壳寡糖对小麦幼苗生长、超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)等抗氧化酶活性的影响。结果表明:不同浓度壳寡糖浸种,对镉胁迫下小麦幼苗生长有促进作用,幼苗高度、根长、生物量均有增加;幼苗叶片中叶绿素含量增高;SOD、POD和CAT活性增加。随着镉胁迫时间的延长,SOD和CAT活性降低,但降低幅度小于对照;POD活性却表现增加,增加的幅度大于对照。壳寡糖不同浓度之间比较,低浓度壳寡糖对镉毒害的缓解效果优于高浓度。说明壳寡糖预处理对镉胁迫有缓解作用。     

Practical performance and its efficiency of arsenic removal from groundwater using Fe-Mn binary oxide

A treatment unit packed by granular adsorbent of Fe-Mn binary oxide incorporated into diatomite (FMBO(1:1)-diatomite) was studied to remove arsenic from anaerobic groundwater without any pre-treatment or post-treatment. The raw anaerobic groundwater containing 35-45 μg/L of arsenic was collected from suburb of Beijing. Arsenic(III) constituted roughly 60%-80% of the total arsenic content. Approximately 7,000 bed volumes (ratio of efluent volume to adsorbent volume) treated water with arsenic concentration below 10 μg/L were produced in the operation period of four months. The regeneration of FMBO(1:1)-diatomite had been operated for 15 times. In the first stage, the regeneration process significantly improved the adsorption capacity of FMBO(1:1)-diatomite. With increased loading amount of Fe-Mn binary oxide, the adsorption capacity for arsenic decreased 20%-40%. Iron and manganese in anaerobic groundwater were oxidized and adsorptive filtrated by FMBO(1:1)-diatomite efficiently. The final concentrations of iron and manganese in efluents were nearly zero. The continued safe performance of the treatment units proved that adsorbent FMBO(1:1)-diatomite had high oxidation ability and exhibited strong adsorptive filtration.     

Cd^2＋对长江华溪蟹谷胱甘肽系统的影响

采用急性毒性方法,研究了Cd2 对长江华溪蟹(Sinopotamon yangtsekiense)肝胰腺和鳃谷胱甘肽系统的影响.Cd2 浓度设置为7.25、14.5、29、58和116 ms/L,同时设对照组.分别在24、48、72和96 h用分光光度法测定了还原型谷胱甘肽(GSH)和氧化型谷胱甘肽(GSSG)含量,谷胱甘肽过氧化物酶(GPx)、谷胱甘肽硫转移酶(GST)和谷胱甘肽还原酶(GR)活力以及GSH/GSSG比值.结果显示,随着Cd2 浓度的增加和处理时间的延长,肝胰腺中GSH含量呈现逐渐降低的趋势,在96 h、Cd2 浓度116 mg/L时GSH含量降至最低值(28.805±2.239)mg/g;GPx活力先升后降;GSSG含量和GST与GR活力均无显著变化.鳃中GSH、GSSG含量和GPx活力的变化趋势与肝胰腺基本一致.GST和GR活力则随着Cd2 浓度的增大和处理时间的延长逐渐降低,在96 h、Cd2 浓度116 mg/L时GST和GR活力较对照组分别下降了44%和79%.肝胰腺和鳃中GSH/GSSG比值随着Cd2 浓度的增大和处理时间的延长逐渐降低.结果表明Cd2 对GSH和GSSG含量.GPx、GST、GR活力均产生了不同程度的影响;GSH/GSSG比值的变化能灵敏反映Cd2 对水生动物的胁迫程度及毒性大小,可作为一种准确敏感的生物学指标用以指示Cd2 污染.     

Cd~(2+)在两性-阴离子复配修饰塿土上的吸附-解吸行为

以十二烷基二甲基甜菜碱(BS-12)单一修饰和十二烷基二甲基甜菜碱+十二烷基磺酸钠(SDS)复配修饰塿土黏化层土壤,采用批处理法研究了Cd2+在供试土样上的吸附-解吸行为,并对其吸附-解吸机制进行了探讨.结果表明,在20℃、40℃下起始浓度较小时,复配修饰土样吸附量大于BS-12单一修饰土样,温度对吸附的影响不大.Langmuir模型最适合描述供试土样对Cd2+的吸附等温线.复配修饰土样20℃、40℃解吸量差异不大,原土和BS-12单一修饰土样随温度升高解吸量增加.土样净吸附量20℃时BS-12单一修饰土样最高,而复配修饰土样和原土差异不大,40℃时复配修饰和单一修饰土样差异不大,但均高于原土.复配土样的吸附是静电作用和有机修饰剂有机相的疏水阻力综合作用的结果.     

Effects of insoluble Zn, Cd, and EDTA on the growth, activities of antioxidant enzymes and uptake of Zn and Cd in Vetiveria zizanioides

A root-bag experiment was conducted to study the effects of insoluble Zn, Cd and ethylenediaminetetraacetic acid (EDTA) on the plant growth, activities of antioxidant enzymes, proline, glutathione (GSH), water-soluble proteins and malondialdehyde (MDA) of Vetiveria zizanioides, and its uptake capacity of Zn and Cd.The results showed that plant growth of V.zizanioides was inhibited by Zn and Cd.The shoot dry weight (SDW) and root dry weight (RDW) decrease by 0.3%, 8.0%, 9.4% and 10.4%, 15.1%, 24.2% compared to the control without EDTA addition, respectively.After adding EDTA, shoot and root dry weight decreased over 10% and 15% compared to results in the absence of EDTA, respectively.The toxicity from insoluble Zn and Cd in soil on SDW and RDW of V.zizanioides was in order: Zn+Cd > Cd > Zn.The activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), and contents of MDA and proline significantly increased, while the contents of GSH and water-soluble proteins markedly decreased with increasing Zn and Cd toxicity.With EDTA, shoot and root Zn concentrations increased in the Zn treatment by 7.3% and 37.4% compared to the plants grown in absence of EDTA.Shoot and root Cd concentrations in the combined Zn and Cd treatment with EDTA increased by 18.6% and 391.9% compared to the treatment without EDTA.However, Zn and Cd concentrations in shoot and roots decreased in the Cd treatment compared to the plants grown in absence of EDTA, with exception of root Cd concentration in the presence of EDTA).     

Soluble protein and acid phosphatase exuded by ectomycorrhizal fungi and seedlings in response to excessive Cu and Cd

Fungi and their symbionts can alleviate heavy metal stress by exuding soluble proteins and enzymes. This study examined the role of soluble protein and acid phosphatase (APase) exuded by Xerocomus chrysenteron, an ectomycorrhizal fungus, and the seedlings of its symbiont, Chinese pine (Pinus tabulaeformis), under conditions of excessive Cu and Cd. The growth type showed that this poorly studied ectomycorrhizal fungus was capable of tolerating high concentrations of Cu, and may be useful in phytoremediation. X. chrysenteron grew well at 80 mg/L Cu, and the EC50 for Cd was 17.82 mg/L. X. chrysenteron also showed enhanced exudation of soluble protein in both isolated and inoculated cultivations under the influence of Cu and Cd. Soluble protein exudation, however, di ered under Cu and Cd stress in isolates. In mediums containing Cu, soluble protein exudation increased with concentration, but in mediums containing Cd the content of soluble protein increased to a comparable level at all concentrations. This study demonstrated that soluble protein was related to heavy metal tolerance, although the di erent ions played di erent roles. While APase activity in exudates of fungi and seedlings decreased under Cu and Cd stress in comparison to the control, the APase activity in seedlings was maintained by inoculation. Thus, X. chrysenteron facilitated the ability of plant to maintain a normal nutrient uptake, and therefore to protect it from heavy metal toxicity.     

常态化疫情防控背景下区域应急医疗物资选址-分配模型*

在常态化疫情防控背景下,为避免本土病例造成区域不同需求主体防护物资短缺问题,构建最小化医院物资集散点需求未满足率加权和、最大化物资购买集中点分配公平性的储备库选址-分配模型,并基于某市相关数据,利用改进的非支配排序遗传算法（NSGA-Ⅱ）进行仿真研究。结果表明:某市应选择储备库数目为5,在物资分配时考虑物资防护等级要求,可减少医院物资集散点物资浪费,增加物资购买集中点获得量。     

不同磷源对土壤镉有效性的影响

本研究采用湖北省具有代表性的黄棕壤和潮土进行室内培养试验,研究了5种磷源和5个施磷量（0、0.1、0.2、0.4、0.8g.kg-1,以每kg土中有效态P2O5含量计）对土壤镉（Cd）有效性的影响.结果表明,培养8周后,随着磷酸氢二铵（DAP）、磷酸二氢铵（MAP）和过磷酸钙（SSP）施入量的增加,两种土壤的pH均显著...     

碱渣对土壤中镉有效性的影响

用盆栽试验研究碱渣及其用量对小白菜(Brassica chinesis)产量、镉吸收量,土壤pH及有效态镉含量的影响,以期为碱渣的利用提供新的途径。结果表明:碱渣对小白菜生长有促进作用,用量3 g/kg时增产效果最佳,与对照相比,增加了48.1%,继续增加用量小白菜产量增加幅度降低;施用碱渣显著提高土壤pH,且pH与施用量呈显著正相关(R=0.792,P<0.05)关系,但土壤有效态镉含量随着碱渣用量的增加呈递增趋势,与对照处理相比,用量为6 g/kg时增加22.0%,达显著水平;碱渣促进根系对镉吸收累积,与对照相比,碱渣处理根系镉含量增加了29.7%~61.0%,达显著水平,并有增加小白菜地上部镉含量的趋势。这说明碱渣能提高土壤镉有效性,促进植物对镉吸收,可用来强化镉污染土壤的植物修复。     

城市河流消落带农产品中铅镉的污染初探

文章以内江市为例,采用石墨炉原子吸收分光光度法对流经内江市区的沱江消落带农产品中重金属铅(Pb)和镉(Cd)的含量进行了初步调查。结果表明,该研究区域农产品中Pb的含量范围为0～0.175 mg/kg,平均值为0.040 mg/kg;Cd的含量范围为0.007～0.077 mg/kg,平均值为0.023 mg/kg;根...