Effects of Ca￣（2＋）ions antagonistic to Al￣（3＋）ions poisoning in root growth，cell division and nucleolus in root tip cells of Allium cepa

ＥｆｆｅｃｔｓｏｆＣａ￣（２＋）ｉｏｎｓａｎｔａｇｏｎｉｓｔｉｃｔｏＡｌ￣（３＋）ｉｏｎｓｐｏｉｓｏｎｉｎｇｉｎｒｏｏｔｇｒｏｗｔｈ，ｃｅｌｌｄｉｖｉｓｉｏｎａｎｄｎｕｃｌｅｏｌｕｓｉｎｒｏｏｔｔｉｐｃｅｌｌｓｏｆＡｌｌｉｕｍｃｅｐａＬｉｕＤｏｎｇｈ...     

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 Cd~(2+) on the nucleolus in root tip cells of Allium cepa

ＥｆｆｅｃｔｓｏｆＣｄ￣（２＋）ｏｎｔｈｅｎｕｃｌｅｏｌｕｓｉｎｒｏｏｔｔｉｐｃｅｌｌｓｏｆＡｌｌｉｕｍｃｅｐａＪｉａｎｇＷｕｓｈｅｎｇ；ＬｉｕＤｏｎｇｈｕａ（ＤｅｐａｒｔｍｅｎｔｏｆＢｉｏｌｏｇｙ，ＴｉａｎｊｉｎＮｏｒｍａｌＵｎｉｖｅｒｓｉｔｙ，Ｔ...     

Cytogenetic studies of chromium(Ⅲ) oxide nanoparticles on Allium cepa root tip cells

The current study evaluates the cytogenetic effects of chromium(Ⅲ) oxide nanoparticles on the root cells of Allium cepa.The root tip cells of A.cepa were treated with the aqueous dispersions of Cr_2O_3 nanoparticles(NPs) at five different concentrations(0.01,0.1,1,10,and 100 μg/m L) for 4 hr.The colloidal stability of the nanoparticle suspensions during the exposure period were ascertained by particle size analyses.After 4 hr exposure to Cr_2O_3 NPs,a significant decrease in mitotic index(MI) from 35.56%(Control) to 35.26%(0.01 μg/m L),34.64%(0.1 μg/m L),32.73%(1 μg/m L),29.6%(10 μg/m L) and 20.92%(100 μg/m L) was noted.The optical,fluorescence and confocal laser scanning microscopic analyses demonstrated specific chromosomal aberrations such as—chromosome stickiness,chromosome breaks,laggard chromosome,clumped chromosome,multipolar phases,nuclear notch,and nuclear bud at different exposure concentrations.The concentration-dependent internalization/bio-uptake of Cr_2O_3 NPs may have contributed to the enhanced production of anti oxidant enzyme,superoxide dismutase to counteract the oxidative stress,which in turn resulted in observed chromosomal aberrations and cytogenetic effects.These results suggest that A.cepa root tip assay can be successfully applied for evaluating environmental risk of Cr_2O_3 NPs over a wide range of concentrations.     

Effects of metal lead on growth and mycorrhizae of an invasive plant species （Solidago canadensis L.）

It is less known whether and how soil metal lead (Pb) impacts the invasion of exotic plants.A greenhouse experiment was conducted to estimate the effects of lead on the growth and mycorrhizae of an invasive species(Solidago canadensis L.)in a microcosm system. Each microcosm unit was separated into HOST and TEST compartments by a replaceable mesh screen that allowed arbuscular mycorrhizal (AM) fungal hyphae rather than plant roots to grow into the TEST compartments.Three Pb levels(control,300,and 600 mg/kg soil)were used in this study to simulate ambient soil and two pollution sites where S. canadensis grows.Mycorrhizal inoculum comprised five indigenous arbuscular mycorrhizal fungal species (Glomus mosseae,Glomus versiform,Glomus diaphanum,Glomus geosporum,and Glomus etunicatum).The 15N isotope tracer was used to quantify the mycorrhizally mediated nitrogen acquisition of plants.The results showed that S. canadensis was highly dependent on mvcOrrhizae.The Pb additions significantly decreased biomass and arbuscular mycorrhizal colonization(root length colonized,RLC%) but did not affect spore numbers,N(including total N and 15N) and P uptake.The facilitating efficiency of mycorrhizae on nutrient acquisition was promoted by Pb treatments.The Pb was mostly sequestered in belowground of plant (root and rhizome).The results suggest that the high efficiency of mycorrhizae on nutrient uptake mightgive S. canadensis a great advantage over native species in Pb polluted softs.     

Effects of Ca2+ ions antagonistic to Al3+ ions poisoningin root growth , cell division and nucleolusin root tip cells of Allium cepa

The effects of different aluminium chloride concentrations together with varying calciumchloride concentrations on root growth, cell division and nucleoli in root tip cells of Allium cepa werestudied. The concentrations used for aluminium chloride were 10^-4, 10^-3 and 10^-2 mol/L ; and for calcium chloride were 10^-5 , 10^-4 , 10^-3 and 10^-2 mol/L, respectively. The results showed that after thetreatments with 10^-2 to 10^-3 mol/L Al³⁺ , root growth was severely inhibited , a large nurnber of thecells with c-mitosis were induced and the nucleolar material was extruded from the nucleus into the cytoplasm. However , the treatments with 10^-2 to 10^-3 mol/L of Al³⁺ together with 10^-2)to 10^-5 mol/LCa²⁺ suggested that Ca²⁺ gave the obviously protective effects against Al³⁺ poisoning in root growth.cell division and nucleoli of the root tip cells in A. cepa. The possible mechanism of these protective effects of Ca²⁺) is also briefly discussed.     

Effect of pH on transport of Pb（2＋）,Mn（2＋）,Zn（2＋）and Ni（2＋） through lateritic soil： Column experiments and transport modeling

This study investigated the e ects of pH on the transport of Pb2+, Mn2+, Zn2+ and Ni2+ through lateritic soil columns. Model results by fitting the symmetric breakthrough curves (BTCs) of bromide (Br??) with CXTFIT model suggested that physical non-equilibrium processes were absent in the columns. The heavy metal BTCs were, however, asymmetrical and exhibited a tailing phenomenon, indicating the presence of chemical non-equilibrium processes in the columns. The retardation factors of Pb2+ were the largest of the four metal ions at both pH 4.0 (33.3) and pH 5.0 (35.4). The use of Langmuir isotherm parameters from batch studies with HYDRUS-1D did not predict the BTCs well. Rather the two-site model (TSM) described the heavy metal BTCs better than the equilibrium linear/nonlinear Langmuir model. The fraction of instantaneous sorption sites ( f ) of all four metal ions on the lateritic soil was consistently about 30%–44% of the total sorption sites.     

Effects of simulated acid rain on root growth of Cunninghamia lanceolata and Schima superba saplings planted in acidified soil

Results from pot culture (with one-year old Cunninghamia lanceolata and Schima superba) are described. It was found that the biomass production and elongation of C. lanceolata was seriously inhibited at pH 2.0 rain, but for S. superba, was not affected markedly. When pH values of experimental rain were higher than 2.0, the root growth of both species was not adversely affected. Aluminium had already accumulated to some degrees in the roots of both trees, and started to affect the root growth of C. lanceolata at pH 2.0 rain. The soil chemistry was also examined. Increased acidity of experimental rain increased the leaching of Ca and Mg. The Al/Ca mol ratio increased from 0.3 to 0.9 in top soil, and in rhizosphere to 1.5 when the pH values of simulated acid rain were 4.5 to 2.0. In this experiment, NO3- fertilization effect was discovered.     

Effects of lead，cadmium，mercury chlorides and aquatic environmental samples on the growth of Escherichia coli

Ｅｆｆｅｃｔｓｏｆｌｅａｄ，ｃａｄｍｉｕｍ，ｍｅｒｃｕｒｙｃｈｌｏｒｉｄｅｓａｎｄａｑｕａｔｉｃｅｎｖｉｒｏｎｍｅｎｔａｌｓａｍｐｌｅｓｏｎｔｈｅｇｒｏｗｔｈｏｆＥｓｃｈｅｒｉｃｈｉａｃｏｌｉＸｕＣｈａｏ（ＤｅｐａｒｔｍｅｎｔｏｆＥｎｖｉｒｏｎｍｅｎ...     

Effects of Cd（Ⅱ） and Cu（Ⅱ） on microbial characteristics in 2-chlorophenol-degradation anaerobic bioreactors

The effects of Cd^2＋ and Cu^2＋ at 300 mg/L on anaerobic microbial communities that degrade 2-cholorophenol （2-CP） were examined. Based on the polymerase chain reaction （PCR） of 16S rDNA, bacterial community diversity and archaeal community structure were analyzed with denaturing gradient gel electrophoresis （DGGE） and cloning, respectively. Degradation capabilities of the anaerobic microbial community were drastically abated and the degradation efficiency of 2-CP was reduced to 60% after shock by Cu^2＋ and Cd^2＋, respectively. The bacterial community structure was disturbed and the biodiversity was reduced after shock by Cu^2＋ and Cd^2＋ for 3 d. Some new metal-resistant microbes which could cope with the new condition appeared. The sequence analysis showed that there existed common Archaea species in control sludge and systems when treated with Cu^2＋ and Cd^2＋, such as Methanothrix soehngenii, Methanosaeta concilii, uncultured euryarchaeote, and so on. Both the abundance and diversity of archaeal species were altered with addition of Cd^2＋ and Cu^2＋ at high concentration. Although the abundance of the predominant archaeal species decreased with Cd^2＋ and Cu^2＋ addition for 3 d, they recovered to some extent after 10 d. The diversity of archaeal species was remarkably reduced after recovery for 10 d and the shift in archaeal composition seemed to be irreversible. The 2-CP-degradation anaerobic system was more sensitive to Cu^2＋ than Cd^2＋.     

Effects of Cu（Ⅱ） and humic acid on atrazine photodegradation

This work was designed to explore the characteristics of photodegradation of herbicides in the copper-polluted water body. The results showed that Cu(II) alone could induce a photo Fenton-like reaction to enhance the degradation of atrazine, in which hydroxyl radical ( OH) was a main active species. Humic acids restrained atrazine degradation, nevertheless, when introducing Cu(II), the photodegradation was accelerated, in which singlet oxygen (1O2) replaced OH acting as the prevailing species. A feasible mechanism for the photochemical process was also proposed, which is helpful for better understanding the environmental photochemistry of atrazine in the copper-polluted water.     

Effects of simulated acid rain on root growth of Cunninghamia lanceolata and Schima superba saplings planted in acidified soil

Results from pot culture (with one-year old Cunninghamia lanceolata and Schima superba) are described. It was found that the biomass production and elongation of C. lanceolata was seriously inhibited at pH 2.0 rain, but for S. superba, was not affected markedly. When pH values of experimental rain were higher than 2.0, the root growth of both species was not adversely affected. Aluminium had already accumulated to some degrees in the roots of both trees, and started to affect the root growth of C. lanceolata at pH 2.0 rain. The soil chemistry was also examined. Increased acidity of experimental rain increased the leaching of Ca and Mg. The Al/Ca mol ratio increased from 0.3 to 0.9 in top soil, and in rhizosphere to 1.5 when the pH values of simulated acid rain were 4.5 to 2.0. In this experiment, NO₃- fertilization effect was discovered.     

Effect of sorbed and desorbed Zn（II） on the growth of a green alga （ Chlorella pyrenoidosa）

Toxic effect of Zn（II） on a green alga （Chlorella pyrenoidosa） in the presence of sepiolite and kaolinite was investigated. The Zn-free clays were found to have a negative impact on the growth of C. pyrenoidosa in comparison with control samples （without adding any clay or Zn（II））. When Zn（II） was added, the algae in the presence of clays could be better survived than the control samples, which was actually caused by a decrease in Zn（II） concentration in the solution owing to the adsorption of Zn（II） on the clays. When the solution system was diluted, the growth of algae could be further inhibited as compared to that in a system which had the same initial Zn（II） concentration as in the diluted system. This in fact resulted from desorption of Zn（II） from the zinc-contaminated clays, although the effect varied according to the different desorption capabilities of sepiolite and kaolinite. Therefore the adsorption and desorption processes of Zn（H） played an important part in its toxicity, and adsorption and desorption of pollutants on soils/sediments should be well considered in natural eco-environmental systems before their risk of toxicity to aquatic organisms was assessed objectively.     

Removal of heavy metals（Cr~（6＋），Ni~（2＋）） from polluted water using decaying leaves of plane（Plantanus orientalis）

Ｒｅｍｏｖａｌｏｆｈｅａｖｙｍｅｔａｌｓ（Ｃｒ~（６＋），Ｎｉ~（２＋））ｆｒｏｍｐｏｌｌｕｔｅｄｗａｔｅｒｕｓｉｎｇｄｅｃａｙｉｎｇｌｅａｖｅｓｏｆｐｌａｎｅ（Ｐｌａｎｔａｎｕｓｏｒｉｅｎｔａｌｉｓ）￥ＴａｎＺｈｉｑｕｎ（ＴｚｉｔｓｃｈｕｎｇＴ．Ｔａ...     

Effects of chitosan on growth of an aquatic plant （Hydrilla verticillata） polluted waters with different chemical oxygen demands

Effects of chitosan on a submersed plant, HydriUa verticillata, were investigated. Results indicated that H. verticillata could prevent ultrastructure phytotoxicities and oxidativereaction from polluted water with high chemical oxygen demand （COD）. Superoxide dismutase （SOD） activity and malondialdehyde （MDA） contents in H. verticillata treated with 0.1% chitosan in wastewater increased with high COD （980 rag/L） and decreased with low COD （63 mg/L）, respectively. Ultrastructural analysis showed that the stroma and grana of chloroplast basically remained normal. However, plant ceils from the control experiment （untreated with chitosan） were vacuolated and the cell interval increased. The relict of protoplast moved to the center, with cells tending to disjoint. Our findings indicate that wastewater with high COD concentration can cause a substantial damage to submersed plant, nevertheless, chitosan probably could alleviate the membrane lipid peroxidization and ultrastructure phytotoxicities, and protect plant cells from stress of high COD concentration polluted water.     

Preparation and luminescence properties of Zn3 （BO3）2 doped with Ce3＋and Mn2＋

采用共沉淀法在700℃和较短的烧结时间下制备了Zn3（BO3）2和不同浓度的Ce3＋、Mn2＋离子掺杂的Zn3（BO3）2纳米晶粉末,对合成产物的发光性质及发光机理进行了研究。利用荧光分光光度计、X射线粉末衍射仪以及透射电镜对其光学性能和纳米晶形貌进行了表征。结果表明Ce3＋离子掺杂的Zn3（BO3）2样品在340～400nm之间有强的荧光发射,其最高发射峰峰位为365nm,在Ce3＋掺量为0.5%（摩尔分数,下同）时发光强度达到最高值。Ce3＋取代Zn2＋离子作为发光中心,Mn2＋离子作为激活剂加入,并不影响荧光发射峰的位置,但能够有效增强其发光强度。当Mn2＋离子掺量为0.7%（摩尔分数）时,Ce3＋、Mn2＋共掺杂的Zn3（BO3）2纳米晶发光强度达到最高值。     

Effects of fluoride on growth and reproduction of the army worm, Mythimna separata (Walker)

This paper deals with effects of airborne fluorine on the army worm, Mythimna separata (Walker), by rearing the larvae on the wheat foliage exposed to HF or fumigating the larvae on the artificial diet with the pollutant. Larval relative growth rate (GR) and index of population trend of the insect reduced by 5% and 11%, respectively, when the larvae were reared on the foliage taken from the wheat plants exposed to 0.87 g·dm-2·day-1 of fluorine compared with those of the control. An extra instar appeared in a majority of the larvae treated. Survival rate and GR of the larvae on the wheat plant being exposure to the same concentration of fluorine in field open-top fumigation device were 40% and 15% lower than that of the control, respectively. Similar experiment with the insect on the artificial diet also showed that direct impact of the pollutant on the army worm was greater than its indirect effect via their host plant.     

Effects of sulfur dioxide on growth,gas exchange rate and leaf sulfur content of massion pine seedlings

Ｅｆｆｅｃｔｓｏｆｓｕｌｆｕｒｄｉｏｘｉｄｅｏｎｇｒｏｗｔｈ，ｇａｓｅｘｃｈａｎｇｅｒａｔｅａｎｄｌｅａｆｓｕｌｆｕｒｃｏｎｔｅｎｔｏｆｍａｓｓｉｏｎｐｉｎｅｓｅｅｄｌｉｎｇｓＹａｎｇＬｉａｎｇＵｎｉｔｅｄＧｒａｄｕａｔｅＳｃｈｏｏｌ，ＴｏｋｙｏＵｎ...     

Effects of methyl-, phenyl-, ethylmercury and mercurychlorid on immune cells of harbor seals （Phoca vitulina）

Mercury (Hg) is present in the marine environment as a natural metal often enhanced through human activities. Depending on its chemical form, Hg can cause a wide range of immunotoxic e ects. In this study, the influence of methyl-, ethyl- and phenylmercury as well as mercurychloride on immune functions was evaluated. Two parameters of cellular immunity, proliferation and mRNA cytokine expression of interleukin-2, -4, and transforming growth factor , were investigated in harbor seal lymphocytes after in vitro exposure to Hg compounds. While all Hg compounds had a suppressive e ect on proliferation, di erences between juvenile and adult seals were found. Lymphocytes from juveniles showed a higher susceptibility to the toxic e ect compared to lymphocytes from adults. Furthermore, the degree of inhibition of proliferation varied among the four Hg compounds. The organic compounds seem to be more immunotoxic than the inorganic compound. Finally, for the cytokine expression of methylmercury-incubated lymphocytes, timedependent changes were observed, but no dose-dependency was found. Marine mammals of the North Sea are burdened with Hg, and lymphocytes of harbor seals may be functionally impaired by this metal. The present in vitro study provides baseline information for future studies on the immunotoxic e ects of Hg on cellular immunity of harbor seals.     

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.