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 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.     

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 resultsby fitting the symmetric breakthrough curves (BTCs) of bromide (Br??) with CXTFIT model suggested that physical non-equilibriumprocesses 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 ofthe 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 withHYDRUS-1D did not predict the BTCs well. Rather the two-site model (TSM) described the heavy metal BTCs better than theequilibrium linear/nonlinear Langmuir model. The fraction of instantaneous sorption sites ( f ) of all four metal ions on the lateriticsoil 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. Theresults showed that Cu(II) alone could induce a photo Fenton-like reaction to enhance the degradation of atrazine, in which hydroxylradical ( OH) was a main active species. Humic acids restrained atrazine degradation, nevertheless, when introducing Cu(II), thephotodegradation was accelerated, in which singlet oxygen (1O2) replaced OH acting as the prevailing species. A feasible mechanismfor the photochemical process was also proposed, which is helpful for better understanding the environmental photochemistry ofatrazine in the copper-polluted water.     

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 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 itschemical form, Hg can cause a wide range of immunotoxic e ects. In this study, the influence of methyl-, ethyl- and phenylmercury aswell as mercurychloride on immune functions was evaluated. Two parameters of cellular immunity, proliferation and mRNA cytokineexpression of interleukin-2, -4, and transforming growth factor , were investigated in harbor seal lymphocytes after in vitro exposureto Hg compounds. While all Hg compounds had a suppressive e ect on proliferation, di erences between juvenile and adult sealswere 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 bemore immunotoxic than the inorganic compound. Finally, for the cytokine expression of methylmercury-incubated lymphocytes, timedependentchanges were observed, but no dose-dependency was found. Marine mammals of the North Sea are burdened with Hg, andlymphocytes of harbor seals may be functionally impaired by this metal. The present in vitro study provides baseline information forfuture studies on the immunotoxic e ects of Hg on cellular immunity of harbor seals.     

Effects of As on As uptake,speciation, and nutrient uptake by winter wheat （Triticum aestivum L.） under hydroponic conditions

A hydroponic experiment was conducted to investigate the effects of arsenic （As） stress on growth, nutrition and As uptake, and speciation in shoots and roots of winter wheat （Triticum aestivum L.）. Winter wheat has high tolerance to As. Most As is accumulated in the roots, and an As concentration of 4,421 mg/kg was observed at a solution concentration of 20 mg/L As. Arsenic concentrations in roots were approximately 40-100 times greater than those in shoots. Arsenic in winter wheat roots and shoots occurred as both As^3＋ and As^5＋ species, although As^3＋ was the main species in winter wheat tissues. Arsenic significantly decreased the biomass of winter wheat shoots and roots and affected absorption and transport of micro- and macro-elements in winter wheat tissue. Arsenic treatment significantly increased the concentrations of total Magnesium （Mg） and calcium （Ca） in shoots and enhanced the transport of Mg and Ca from roots to shoots but decreased potassium （K）, nitrogen （N）, and phosphorus （P） concentrations in both shoots and roots, particularly the concentration of P. Concentrations of iron, copper, and zinc in winter wheat shoots were negatively related to As rates, with correlation coefficients （R^2） of 0.93, 0.94, and 0.97, respectively.     

Effect of ionic strength on adsorption of As（Ⅲ） and As（Ⅴ） on variable charge soils

The study was to investigate the adsorption behavior of arsenite (As(Ⅲ)) and arsenate (As(Ⅴ)) on two variable charge soils, i.e., Haplic Acrisol and Rhodic Ferralsol at different ionic strengths and pH with batch methods. Results indicated that the amount of As(Ⅲ) adsorbed by these two soils increased with increasing solution pH, whereas it decreased with increasing ionic strength under the acidic condition. This suggested that As(Ⅲ) was mainly adsorbed on soil positive charge sites through electrostatic attraction under the acidic condition. Moreover, intersects of As(Ⅴ) adsorption-pH curves at different ionic strengths (a characteristic pH) are obtained for both soils. It was noted that above this pH, the adsorption of As(Ⅴ) was increased with increasing ionic strength, whereas below it the reverse trend was true. Precisely the intersect pH was 3.6 for Haplic Acrisol and 4.5 for Rhodic Ferralsol, which was near the values of PZSE (soil point of zero salt effect) of these soils. The effects of ionic strength and pH on arsenate adsorption by these soils were interpreted by the adsorption model. The results of zeta potential suggested that the potential in adsorption plane becomes less negative with increasing ionic strength above soil PZSE and decreases with increasing ionic strength below soil PZSE. These results further supported the hypothesis of the adsorption model that the potential in the adsorption plane changes with ionic strength with an opposite trend to surface charge of the soils. Therefore, the change of the potential in the adsorption plane was mainly responsible for the change of arsenate adsorption induced by ionic strength on variable charge soils.     

Effects of temperature on population growth and intake of food by the army worm, Mythimna separata (Walker)

Population life tables of the army worm, Mythimna separata, were constructed and nutritional parameters of food for the larvae were examined at 5 temperatures from 16℃ to 32℃. The temperature suitable for growth and reproduction of the insect ranged from 20℃ to 28℃ with the optimum of 24℃. Their survivalship and fecundity were much poorer at 32℃ than at 16℃. Indices of population trend of the insect at these temperatures could well fitted with the parabolic curve which theoretically indicated that the population density would multiply by some 660 after one generation circle at the optimal temperature, 22.6℃, and it would decline at temperatures higher than 32.9℃ or lower than 12.3℃. Larval food intake and their AD tended to go up while their ECI and ECD to go down with a rise in temperature. These alterations in population size and feeding behavior caused by temperature would exert an important effect on their damage to crops.     

Effects of lanthanum（Ⅲ） on nitrogen metabolism of soybean seedlings under elevated UV-B radiation

The hydroponic culture experiments of soybean bean seedlings were conducted to investigate the effect of lanthanum(La)on nitrogen metabolism under two different levels of elevated UV-B radiation(UV-B,280-320 nm).The whole process of nitrogen metabolism involves uptake and transport of nitrate,nitrate assimilation,ammonium assimilation,amino acid biosynthesis,and protein synthesis. Compared with the control,UV-B radiation with the intensity of low level 0.15 W/m~2 and high level 0.45 W/m~2 significantly affected the whole nitrogen metabolism in soybean seedlings(p<0.05).It restricted uptake and transport of NO_3~-,inhibited activity of some key nitrogen-metabolism-related enzymes,such as:nitrate reductase(NR)to the nitrate reduction,glutamine systhetase(GS)and glutamine synthase(GOGAT)to the ammonia assimilation,while it increased the content of free amino acids and decreased that of soluble protein as well.The damage effect of high level of UV-B radiation on nitrogen metabolism was greater than that of low level. And UV-B radiation promoted the activity of the anti-adversity enzyme glutamate dehydrogenase(GDH),which reduced the toxicity of excess ammonia in plant.After pretreatment with the optimum concentration of La(20 mg/L),La could increase the activity of NR, GS,GOGAT,and GDH,and ammonia assimilation,but decrease nitrate and ammonia accumulation.In conclusion,La could relieve the damage effect of UV-B radiation on plant by regulating nitrogen metabolism process,and its alleviating effect under low level was better than that under the high one.     

Effect of water regimes and organic matters on transport of arsenic in summer rice （Oryza sativa L.）

The arsenic contamination in soil-water-plant systems is a major concern of where, the groundwater is being contaminated witharsenic (above 0.01 mg/L) in the Indian subcontinent. The study was conducted with organic matter to find out the reducing e ect onarsenic load to rice (cv. Khitish). It was observed that intermittent ponding reduced arsenic uptake (23.33% in root, 13.84% in shoot and19.84% in leaf) at panicle initiation stage, instead of continuous ponding. A decreasing trend of arsenic accumulation (root > straw >husk > whole grain > milled grain) was observed in di erent plant parts at harvest. Combined applications of lathyrus + vermicompost+ poultry manure reduced arsenic transport in plant parts (root, straw, husk, whole grains and milled grain) which was significantly atpar (p > 0.05) with chopped rice straw (5 tons/ha ) + lathyrus green manuring (5 tons/ha) in comparison to control and correspondingsoils. A significant negative correlation of arsenic with phosphorus (grain P with arsenic in di erent parts R2= 0.627–0.726 at p >0.01) was observed. Similarly, soil arsenic had a negative correlation with soil available phosphorus (R2 = 0.822 at p > 0.001) followedby soil nitrogen (R2= 0.762 at p > 0.01) and soil potassium (R2 = 0.626 at p > 0.01). Hence, e ective management of contaminatedirrigation water along with organic matter could reduce the arsenic build up to plants and soil.