Effects of Zn2+ on root growth,cell division, and nucleoli of Allium cepa L.

The effects of different concentrations of Zn²⁺ion on root growth,cell division,and nucleoli of Allium cepa were studied. The test Zn²⁺ ion concentration was made up from zinc sulphate (ZnSO₄. 7H₂O) ranging from 10^-7 to 10^-2 mol/L. The solutions were prepared in tap water (pH =6. 5).The results indicated that Zn²⁺ could obviously inhibit root growth at concentrations from 10^-4)to 10^-2 mol/L.Roots treated with zinc sulphate showed the presence of c-mitosis, anaphase bridges,including sticky and fluidized bridges (at 10^-3 to 10^-2 mol/L) , chromosome stickiness, irregularly shaped nuclei, broken nuclei and micronuclei. A toxicity effect was also observed on the nucleoli using silver staining technique after 48h of treatment with 10^-4to 10^-2 mol/L Zn²⁺, e. g,the nucleolar particulate material scattered around the nucleoli in the nucleus of root tip cells.     

Effects of Cd2+ on the nucleolus in root tip cells of Allium cepa

The effects of different concentrations of cadmium chloride ranging from 0.5 to 20 ppm on the nucleolus in root tip cells of Allium cepa were studied using the silver staining technique. The results indicated that after the treatment with Cd²⁺,different changes in nucleolar morphology appeared. The nucleolar material was extruded from the nucleus into the cytoplasm,and the nucleoli at mitotic metaphase did not disappear. Apparently,cadmium showed a specific effects on the nucleoli in root tip cells of Allium cepa. The possible mechanism behind this phenomenon is also briefly discussed.     

3类金属离子对活性污泥吸附水体腐殖酸的影响

研究了3类金属离子对活性污泥吸附水体腐殖酸效果的影响.结果表明,盐类金属离子(Na )、硬度金属离子(Ca2 、Mg2 )和水解金属离子(Al3 、Fe3 )均能在一定程度上提高吸附效率.作为活性污泥助凝剂,以大于10-2mol/L硬度离子的促进效果为好.加入10-2mol/L Ca2 、Mg2 48 h后溶液中的腐殖酸浓度分别为(0.64±0.17)mg/L和(2.32±0.40)mg/L,其去除率分别为98.4%和94.2%;当加入10-1mol/L Ca2 、Mg2 48 h后,其去除率均接近100%,而且Ca2 离子促进作用要优于Mg2 .盐类金属离子、硬度金属离子、水解金属离子提高活性污泥吸附腐殖酸的主要作用机理可能分别是压缩双电层、架桥作用、吸附共沉淀.同时,投加金属离子也可能使活性污泥上的吸附位性质改变或失效,对腐殖酸的吸附有一定的负面影响.     

二氯化汞对人外周血淋巴细胞的遗传毒性及硒的防护作用

环境中的汞对人体健康有潜在危害性。它可与DNA中的不同组分相互作用,引起DNA链断裂和诱发染色体畸变。近来研究表明,硒对汞的毒作用具有防护效应,这对于估价汞的健康损害作用似是一个重要的修饰因子。但是,有关硒对汞化合物引起的DNA     

Uptake and accumulation of copper by roots and shoots of maize (Zea mays L.)

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｃｏｎｔｅｎｔｏｆＣｕｉｎｔｈｅｅｎｖｉｒｏｎｍｅｎｔｉｓｕｓｕａｌｌｙ20ｔｏ30ｐｐｍｉｎｎｏｎｃｏｎｔａｍｉｎａｔｅｄｓｏｉｌ(Ｎｒｉａｇｕ,1979;Ｓａｌｏｍｏｎｓ,1984),ｂｕｔｉｓｍｏｒｅｔｈａｎ2000ｐｐｍｉｎｍｉｎｉｎｇａｒｅａｓａｎｄｉｎｔｈｅｖｉｃｉｎｉｔｙｏｆｓｍｅｌｔｅｒｓ(Ｆｒｅｅｄｍａｎ,1980;Ｈｕｍｐｈｒｅｙｓ,1984).ＩｔｈａｓｂｅｅｎｄｅｍｏｎｓｔｒａｔｅｄｔｈａｔｃｏｐｐｅｒｓｏｌｕｂｉｌｉｔｙｄｅｐｅｎｄｓｏｎｐＨｉｎｓｏｉｌｓ,ａｎｄｉｔｉｓｏｂ…     

Uptake and accumulation of copper by roots and shoots of maize(Zea may L.)

The effects of different concentrations of copper sulfate on rootand shoot growth of maize(Zea mays L.) and the uptake and accumulation of Cu2+ by its roots and shoots were investigated in the present study. The concentrations of opper sulfate (CuSO4.5H2O) used were in the range of 10-5-10-3mol/L. Root growth decreased progressively with increasing concentration of Cu2+ in solution. The seedlings exposed to 10-3 mol/L Cu exhibited substantial growth reduction, yielding only 68% of the root length of the control. The shoot growth of the seedlings grown at 10-5-10-4 mol/L Cu2+ were more or less than the same as the control seedlings. The leaves treated with 10-3 mol/L Cu2+ were obviously inhibited in shoot growth. The fresh and dry weights both in roots and shots decreased progressively with increasing Cu2+ concentration.This fits well with the above mentioned effects of copper sulfate on root growth. Zea mays has considerable ability to remove Cu from solutions and accumulate it. The Cu content in roots of Z. Mays increased with increasing solution concentration of Cu2+. The amount of Cu in roots of plants treated with 10-3, 10-4 and 10-5 mol/L Cu2+ were 10, 8 and 1.5 fold, respectively, greater than that of roots of control plant. However, the plants transported and concentrated only a small amount of Cu in their shoots.     

强化混凝对腐殖酸和富里酸去除对比研究

以腐殖酸和富里酸为研究对象,考察了硫酸铝、三氯化铁、聚合氯化铝和聚合氯化铁这4种混凝剂的强化混凝效果,并研究了pH、浊度及Ca2+、腐殖酸和富里酸相对含量对强化混凝的影响.结果表明,4种混凝剂对腐殖酸的去除效果要高于富里酸,三氯化铁和硫酸铝比聚合氯化铝和聚合氯化铁具有更好的混凝效果,在混凝剂投量为40 mg.L-1时,三氯化铁、硫酸铝、聚合氯化铁和聚合氯化铝混凝后可将水样中富里酸浓度由10 mg.L-1分别降为3.22、4.34、5.85和4.86 mg.L-1,而腐殖酸浓度可分别降至1.13、2.13、3.44和2.50 mg.L-1.三氯化铁和硫酸铝强化混凝的最佳pH为5.5～6.5,在其它pH范围强化混凝效果降低;水样中有机物浓度越高,混凝效果越差,富里酸/腐殖酸>0.4后混凝效果明显变差.浊度对混凝剂去除有机物的影响较小,Ca2+浓度的增加可提高腐殖酸和富里酸的去除效果.     

Species distribution of polymeric aluminium-ferrum--timed complexation colorimetric analysis method of Al-Fe-Ferron

ＩｎｔｒｏｄｕｃｔｉｏｎＴｕｒｎｅｒｆｉｒｓｔａｄｏｐｔｅｄｔｈｅＡｌ ｆｅｒｒｏｎｍｅｔｈｏｄａｓａｎｉｎｄｉｒｅｃｔａｎａｌｙｓｉｓｍｅｔｈｏｄｔｏｄｅｔｅｒｍｉｎｅｔｈｅｓｐｅｃｉｅｓｄｉｓｔｒｉｂｕｔｉｏｎｏｆＡｌ ｓｏｌｕｔｉｏｎｓｉｎ 1969(Ｔｕｒｎｅｒ,1969) .Ｔｈｉｓｍｅｔｈｏｄｈａｓｂｅｅｎｉｍｐｒｏｖｅｄａｎｄｉｓｓｔｉｌｌｕｓｅｄａｔｐｒｅｓｅｎｔａｎｄｉｔｐｌａｙｓａｋｅｙｒｏｌｅｉｎｓｔｕｄｙｉｎｇｔｈｅｄｉｓｔｒｉｂｕｔｉｏｎａｎｄｔｒａｎｓｆｏｒｍａｔｉｏｎｏｆｓｐｅｃｉ…     

镉对大鼠肾皮质结合反应的影响

通过体内和体外试验分别研究了镉对肾皮质微粒体谷胱甘肽转移酶(GST)及游离肾近曲小管细胞中葡萄糖醛酸(GA)结合反应的影响.结果表明:(1)体外试验中,在10~(-7)—10~(-3)mol/L浓度范围内,镉可抑制肾皮质微粒休GST活力;(2)体内腹腔注射CdCl_2(2.4mg/kg,连续3天)后,大鼠肾皮质GST活力无明显改变;(3)按同样方式腹腔注射CdCl_2后,可降低游离肾近曲小管细胞中GA和7-羟基香豆素(7-HC)的结合反应;(4)体外试验中,低浓度镉(10~(-7)mol/L)可使肾皮质细胞中GA和7-HC的结合反应增强,而在10~(-6)—10~(-2)mol/L浓度范围内,镉可降低GA和7-HC的结合反应.     

Ca2+、Al3+对聚丙烯酰胺在高岭土絮凝过程中作用的影响

在实验条件下,Ca²⁺、Al³⁺离子对高岭土的絮凝过程有不利影响,且pH越高Ca²⁺的影响越大,pH越低,Al³⁺的影响越大.运用分子轨道(MO)理论、溶液化学计算、电子探针测试等手段,研究探讨了其作用机理.认为在酸性和中性范围内,Ca²⁺、Al³⁺离子及它们的羟基络合正离子与聚丙烯酰胺之间的相互作用造成后者分子链发生卷曲,导致絮凝效果下降;而在pH>9范围内,Ca²⁺、Al³⁺的氢氧化物沉积在高岭土表面,阻碍或抑制了聚丙烯酰胺与高岭土之间的氢键作用.     

异步周期换向电凝聚法处理活性艳蓝X-BR模拟染料废水及其机理研究

针对传统电凝聚法处理废水过程中易出现的电极表面钝化和极化而影响处理效果的现象,采用铝和铁板作为两极同步换向方法,通过周期性改变电流方向使电极钝化和极化现象得以减缓或消失,并实现两极均可溶,利用铝、铁系无机絮凝剂共存时可提高处理效果的特点,对活性艳蓝X-BR模拟染料废水进行处理;通过正交试验,获得了该方法的最佳处理条件.在此基础上,为避免金属铝成分在废水中出现剩余影响水质,采用异步周期换向方式加以改进,考察了铝、铁电极不同通电时间对处理效果的影响,并利用紫外-可见光分光光度法、高效液相色谱法、ICP法、高分辨质谱技术、激光粒度分析仪等手段对废水处理过程主导因素和污染物去除机理以及该方法对强化处理效果的作用机理进行了分析.研究表明,最佳条件下采用异步换向周期电凝聚法处理活性艳蓝X-BR模拟染料废水30 min可使模拟废水脱色率接近100%,COD去除率可达76%以上;处理过程中起主导作用的是电凝聚过程而非电氧化还原过程;除大部分染料分子被电凝聚气浮或沉降导致脱色外,其余的活性艳蓝X-BR染料分子在电解作用下首先断裂生成了1,4-二氨基蒽醌-2-磺酸根,之后1,4-二氨基蒽醌-2-磺酸根又被直接絮凝上浮或沉降,或者在氢离子作用下发生了加氢反应使双键消失而脱色,模拟废水脱色是上述作用的综合结果.采用改进后的异步周期换向电凝聚法可以使铝铁离子凝聚过程形成的絮体具有更为合理的粒度和结构特性,从而更易于被去除,因此处理效果略优于同步换向和定向电流电凝聚过程,且可以实现处理后废水中铝离子含量降低到无法检出,避免其在处理后的废水中出现剩余影响水质.     

1株草螺属植物内生菌R-13的分离鉴定及对龙葵吸收土壤镉的影响

植物内生菌联合超积累植物修复重金属污染土壤可显著提高植物修复效率.从镉污染稻田水稻根系中分离获得1株编号为R-13的植物内生菌.分别利用显微观察、碳源利用及分子生物学手段将该菌株鉴定为1株红苍白草螺菌（Herbaspirillum rubrisubalbicans）;该菌株具有较强的耐Cd²⁺能力,在镉含量为300 mg·kg^-1的固体培养基上仍能生长.经显色反应发现R-13菌株具有产生铁载体和分泌吲哚乙酸（IAA）能力,此外,经Pikovskaya''s固体培养基和Ashby固体培养基试验表明R-13菌株溶磷作用微弱,但是具有较强的固氮能力.在盆栽试验中,利用高通量测序技术追踪R-13菌株在龙葵根部定殖情况,发现接种1次3 d后草螺菌属在龙葵根系内相对丰度相比空白对照（CK）增加201.88%,两次接种可使草螺菌属在龙葵根部的相对丰度相比CK增加1182.44%,接种5 d后草螺菌属在龙葵根系内相对丰度开始出现显著降低趋势.当接种20 mL·pot^-1菌液时对龙葵的根、茎、叶及果实中镉含量无显著影响,当接种菌液达到40 mL·pot^-1时可显著提高龙葵营养器官中的镉含量,当接种量达到200 mL·pot^-1时龙葵营养器官中镉含量最高.此时,根系中镉含量与对照组相比提高84.42%,茎秆中提高43.67%,叶片中提高64.06%,果实中提高20.29%.综上可见,根系接种植物内生草螺菌R-13可显著提高龙葵根系中草螺菌属的相对含量,同时可起到强化龙葵吸收镉的作用,该菌株在植物修复镉污染土壤技术中具有较好应用前景.     

新生态MnO2强化混凝去除苯酚的影响因素研究

以苯酚为目标物,考察钙离子、单宁酸、高岭土投量、新生态二氧化锰投量、pH等条件对新生态二氧化锰强化氯化铝混凝去除苯酚的影响.结果表明,钙离子能够促进新生态二氧化锰强化混凝对苯酚的去除,在钙离子投加范围内（0～1.0mmol.L-1）,苯酚的去除率能提高10%左右;单宁酸与苯酚共存时,能显著促进苯酚的去除,当单宁酸投加1...     

亚热带可变电荷土壤磷素淋失临界点及其与土壤特性的关系

选取我国亚热带地区16种典型可变电荷土壤,通过室内模拟试验测定其磷素(P)淋失临界点的Olsen-P含量,以及可能对其构成有影响的8个化学性质指标(pH、CEC、粘粒、有机质、交换性钙、镁和铁铝氧化物含量),以探讨可变电荷土壤P淋失临界点的特点及其与土壤相关性质的关系,并评价当前的P淋失潜在风险.结果表明:可变电荷土壤P淋失临界点的Olsen-P含量(56 ～ 123 mg·kg-1)差异很大,旱地土壤临界点Olsen-P含量主要集中在低值区间(＜60 mg·kg-1),而水稻土临界点Olsen-P含量集中在高值区间(＞80 mg·kg-1);旱地土壤P淋失风险高于水稻土.主成分分析显示,可变电荷土壤的pH、粘粒、CEC、有机质、交换性钙镁、氧化铁铝等化学性质同时对其临界点Olsen-P含量构成正的或负的影响.因此,临界点Olsen-P含量与单一因素的回归分析不仅不能够确切地反映临界点Olsen-P含量与这些化学性质的关系(与pH、CEC、粘粒、交换性钙镁含量无显著相关),甚至与理论上的关联相违(与氧化铁铝含量呈负相关).与以往研究结果比较,可变电荷土壤在旱作和稻作下的P淋失临界点的Olsen-P含量都普遍高于永久电荷土壤,研究的16种可变电荷土壤的实际Olsen-P含量也远低于临界点Olsen-P含量,由此推断南方地区耕作土壤的P淋失风险仍较小.     

Effects of nitrogen and phosphorus concentrations on the bioaccumulation of polybrominated diphenyl ethers by Prorocentrum donghaiense

The growth, cellular total lipids, bioaccumulation amount, and bioaccumulation factors (BAFs) of 2,4,4 ′ -tribromodiphenyl ether (BDE28), 2,2 ′ ,4,4 ′ -tetrabromodiphenyl ether (BDE47), and 2,2 ′ ,4,4 ′ ,5-pentabromodiphenyl ether (BDE99) in a semi-continuous culture of Prorocentrum donghaiense were studied in relation to nitrate (0, 128, and 512 μmol/L) and phosphate (0, 8, and 32 μmol/L) concentrations. The BDE28, BDE47, and BDE99 content per cell under 0 μmol N/L were 3.77 × 10 6 , 3.95 × 10 6 , and 4.32 × 10 6 ng/cell, respectively, which were significantly higher than those under 128 and 512 μmol N/L. A nearly 5-fold increase in polybrominated diphenyl ether (PBDE) content per algal cell was found between 0 and 8 μmol P/L and between 8 and 32 μmol P/L. With increasing N and P concentrations, the PBDE content per volume of algal culture and the accumulation percentage of available PBDEs declined slightly. The BAFs for the PBDEs based on lipids showed that the logBAF lip under 0 μmol N/L was higher than those under 128 and 512 μmol N/L. The logBAF lip under 0 μmol P/L was higher than that under 8 μmol P/L but lower than that under 32 μmol P/L. Correlation analysis indicated a significant negative correlation between nutrient concentration and cellular total lipids, as well as the PBDE content per cell. The results indicate that different N and P concentrations change the total lipids content of P. donghaiense, thereby resulting in varying PBDE accumulation.     

铅与丁草胺的交互作用对油麦菜生长和抗氧化酶活性的影响

盆栽土培试验研究了重金属铅与除草剂丁草胺的复合污染对油麦菜生长及生理生化的毒性效应.结果表明土壤铅浓度小于500mg.kg-1对油麦菜发芽率的影响不明显,铅浓度为150mg.kg-1对油麦菜株高有促进作用,但对叶片过氧化物酶（POD）和过氧化氢酶（CAT）活性有明显抑制作用.土壤铅浓度为500mg.kg-1时,油麦菜根...     

绿狐尾藻对铜绿微囊藻和羊角月牙藻的抑藻效应

分别将不同起始浓度(10~5、10~6、10~7、10~8和10~9ind.·L~(-1))的铜绿微囊藻和羊角月牙藻分组与绿狐尾藻进行共培养,连续10 d,每天测定各组铜绿微囊藻或羊角月牙藻的光密度值,用以确定绿狐尾藻对两种藻类不同浓度的生长抑制情况.结果表明,2. 5 g·(200 m L)~(-1)的绿狐尾藻对起始浓度为10~7ind.·L~(-1)和10~8ind.·L~(-1)的铜绿微囊藻具有明显的抑制作用;而对实验所设的所有起始浓度的羊角月牙藻生长均没有显著的抑制作用.并且,采用溶剂浸提与气相色谱-质谱联用(GC-MS)测定的方法,分析了绿狐尾藻粉末浸提液和绿狐尾藻生长液中可能存在的化感物质,通过分析,确定棕榈酸是绿狐尾藻分泌的化感物质之一,并且发现了3种可能是绿狐尾藻分泌的新型化感物质:3-乙基-3-甲基庚烷、磷酸三乙酯和酞酸二丁酯.     

Adsorptive behaviors of humic acid onto freshly prepared hydrous manganese dioxides

This study focused on the adsorptive behaviors of humic acid onto freshly prepared hydrous MnO₂(s) (δMnO₂), and investigated the feasibility of employing δMnO₂ for humic acid removal from drinking water. Effects of such parameters as molecular mass of humic acid, kinds of divalent cations on adsorptive behaviors and possible mechanisms involved were investigated. This study indicated that humic acid with higher molecular mass exhibited more tendency of adsorbing onto δMnO₂ than that with lower molecular mass. Ca²⁺ facilitated more humic acid adsorption than Mg²⁺; UV-Vis spectra analysis indicated higher capabilities of Ca²⁺ coordinating with acidic functional groups of humic acid than that of Mg²⁺. Additionally, ζ potential characterization indicated that Ca²⁺ showed higher potential of increasing gz potential of δMnO₂ than Mg²⁺. Ca²⁺ of 1.0 mmol/L increased ζ potential of δMnO₂ from −37 mV (pH 7.9) to +7 mV (pH 7.2), while 1.0 mmol/L Mg²⁺ increased to lower value as −9 mV (pH 6.5), correspondingly. Fourier transform infrared (FTIR) spectra demonstrated the adsorption of humic acid onto δMnO₂, showing the important roles of-COO⁻ functional groups and surface Mn-OH in the adsorption of humic acid onto δMnO₂. Translated from Acta Scientiae Circumstantiae, 2005, 25(3): 351–355 [译自: 环境科学学报]     

Al3+对序批式生物膜反应器(SBBR)中污泥脱氢酶活性(DHA)和胞外聚合物(EPS)的影响

通过向序批式生物膜反应器(SBBR)中投加氯化铝,研究了化学协同生物除磷过程中Al~(3+)对污泥脱氢酶活性(DHA)、胞外聚合物(EPS)及系统处理效果的影响.结果表明,氯化铝投加量少于0.1 mmol·L~(-1)时,Al~(3+)对微生物的活性有促进作用,多于0.1 mmol·L~(-1)的Al~(3+)对其活性有明显的抑制作用.氯化铝投加量少于0.1 mmol·L~(-1)时,Al~(3+)能够促进EPS中多糖(PS)和蛋白质(PN)的分泌,多于0.1 mmol·L~(-1)的Al~(3+)则只促进多糖的分泌,但对EPS的分泌总量没有影响.Al~(3+)会使污泥的SVI值显著降低,大大改善其沉降性能.MLSS、MLVSS基本上是随着Al~(3+)投加量的增加而增大,MLVSS/MLSS随着投药量的增加先减小后增大再减小.Al~(3+)对COD和TN的去除具有轻微抑制作用,但对TP的去除具有显著的改善作用.当Al~(3+)的投加为0.5 mmol·L~(-1)时,TP的去除效果最好,出水浓度仅为0.44 mg·L~(-1),满足一级A排放标准.此时,TP的去除率为92.7%,比不加药时提升了10.2%.     

水解聚合铝溶液中形态分布的定量模拟研究

通过Ａｌ－Ｆｅｒｒｏｎ逐时络合比色法和￣（２７）Ａｌ核磁共振（ＮＭＲ）法，并应用“ＭＩＮＥＱＬ”化学平衡模式计算法，对采用不同反应途径制得的聚合铝（ＰＡＣ）溶液中的化学形态分布规律进行了定量模拟研究和对比。模式计算结果与两种实验定量分析结果都较为吻合，结果表明，在水解聚合铝溶液中较稳定的化学形态主要有五种：一种单体形态［ａｌ＿ａ］，即Ａｌ￣（３＋），Ａｌ（ＯＨ）￣（２＋），Ａｌ（ＯＨ）＿２￣＋；３种聚合形态［Ａｌ＿ｂ］，即和以及一种溶胶或凝胶形态［Ａｌ＿ｃ］，即Ａｌ（ＯＨ）＿３（ａｍ）．这些化学形态的分布和转化不仅取决于溶液的化学特征，而且也取决于制备方法的不同。