Accumulation of Fluoride and Aluminium Related to Different Varieties of Tea Plant

Samples of young shoot, mature leaf, twig, root, and litter were taken from four recently bred varieties Zhe-nong 113, Zhe-nong 121, Zi-sun, and Bi-feng grown at two tea plantations located at Zhejiang and Jiangsu Provinces. The results showed that the concentrations of F and Al in tea plants were significantly different among the four varieties. It is therefore possible that F and Al concentrations in tea products can be reduced through variety selection. The results also revealed that old leaves would be the major contribution to the high levels of F and Al in brick tea since it is produced mainly for old leaves. Therefore, in order to eliminate the hazard of over-exposure to F and Al derived from tea, younger shoot should be used for making tea products while mature leaves should be avoided.     

Remediation of copper-contaminated topsoils from a wood treatment facility using in situ stabilisation

Five organic matters, three phosphate compounds, zerovalent iron grit (ZVIG, 2% by soil weight), two alkaline compounds, and two commercial formulations were incorporated, singly and some combined with ZVIG, into a highly Cu-contaminated topsoil (Soil P7, 2600 mg Cu kg⁻¹) from a wood treatment facility. Formulations and two composts were also singly incorporated into a slightly Cu-contaminated topsoil (Soil P10, 118 mg Cu kg⁻¹) from the facility surrounding. This aimed to reduce the labile pool of Cu and its accumulation in beans cultivated on potted soils in a climatic chamber. Lowest Cu concentration in soil solution occurred in P7 soils amended with activated carbon (5%) and ZVIG, singly and combined. Basic slag (3.9%) and compost of sewage sludge (5%) combined with ZVIG promoted shoot production and limited foliar Cu accumulation. For amended P10 soils, no changes occurred in soil solution and foliar Cu concentrations, but one compost increased shoot production.     

家蚕斑纹限性品种SC_1的RAPD差异DNA片段的克隆及其酶切图谱分析

利用RAPD技术对家蚕限性普斑品种SC1的雌雄体分别进行PCR扩增通过120种引物的筛选，得到1个雌体特异的RAPDDNA片段将该片段克隆到pUC19质粒，井进行了限制性内切酶图谱分析.     

Leaf accumulation of trace elements and polycyclic aromatic hydrocarbons (PAHs) in Quercus ilex L

Quercus ilex L. leaves were collected four times in one year at six urban sites and one remote area in order to determine trace element and PAH accumulation through concomitant analyses of unwashed and water-washed leaves. Both unwashed and washed leaves showed the highest amounts of trace elements and PAHs in the urban area. Unwashed leaves showed greater differences between urban and remote areas and among the urban sites than washed leaves for trace element and PAH concentrations. Water-washing resulted in a significant (P<0.001) decrease in leaf concentrations of Cr, Cu, Fe, Pb, V and Zn. By contrast, Cd and total PAH concentrations showed no differences between unwashed and washed leaves.     

Plant and Soil System Responses to Ozone After 3 Years in a Lysimeter Study with Juvenile Beech (Fagus sylvatica L.)

A lysimeter study was performed to monitor effects of elevated ozone on juvenile trees of Fagus sylvatica L. as well as on the plant–soil system. During a fumigation period over almost three growing seasons, parameters related to plant growth, phenological development and physiology as well as soil functions were studied. The data analyses identified elevated ozone to delay leaf phenology at early and to accelerate it at late developmental stages, to reduce growth, some leaf nutrients (Ca, K) as well as some soluble phenolics (hydroxycinnamic acid derivatives, total flavonol glycosides). No or very weak ozone effects were found in mobile carbon pools of leaves (starch, sucrose), and other phenolic compounds (flavans). Altered gene expression related to stress and carbon cycling corresponded well with findings from leaf phenology and chemical composition analyses indicating earlier senescence and oxidative stress in leaves under elevated ozone. Conversely in the soil system, no effects of ozone were detected on soil enzyme activities, rates of litter degradation and lysimeter water balances. Despite the fact that the three reported years 2003–2005 were climatically very contrasting including a hot and dry as well as an extremely wet summer, and also mild as well as cold winters, the influence of ozone on a number of plant parameters is remarkably consistent, further underlining the phytotoxic potential of elevated tropospheric ozone levels.     

Changes of organic acid exudation and rhizosphere pH in rice plants under chromium stress.

The effect of chromium (Cr) stress on the changes of rhizosphere pH, organic acid exudation, and Cr accumulation in plants was studied using two rice genotypes differing in grain Cr accumulation. The results showed that rhizosphere pH increased with increasing level of Cr in the culture solution and with an extended time of Cr exposure. Among the six organic acids examined in this experiment, oxalic and malic acid contents were relatively higher, and had a significant positive correlation with the rhizosphere pH, indicating that they play an important role in changing rhizosphere pH. The Cr content in roots was significantly higher than that in stems and leaves. Cr accumulation in plants was significantly and positively correlated with rhizosphere pH, and the exudation of oxalic, malic and citric acids, suggesting that an increase in rhizosphere pH, and exudation of oxalic, malic and citric acid enhances Cr accumulation in rice plants.     

铅锌冶炼厂周边农田土壤、苕子与荠菜的重金属污染特征

在云南某铅锌矿冶炼厂周边农田,采集当地主要绿肥(苕子)与野菜(荠菜)的植株和根部土壤样品,测定重金属(Pb、Zn、Cu和Cd)的全量和DTPA提取的有效态质量比,并进行污染评价.结果表明:1)综合污染指数评价显示,铅锌冶炼厂周边农田土壤以重度和中度重金属污染为主,Cd质量比为GB 15618-1995《土壤环境质量标准》三级标准限值的1.94～8.30倍,污染程度最重,其次为Pb和Zn;2)荠菜植株Pb、Zn和Cd质量比的最大值、平均值均大于苕子;荠菜对Cd的富集系数大于1,对Pb、Zn和Cd的转移系数大于或接近1;3)苕子和荠菜地上部与土壤的Cd、Pb质量比,苕子地下部与土壤的Pb质量比,荠菜地上部与土壤的Zn质量比均呈显著或极显著正相关.研究表明:铅锌冶炼厂周边农田存在严重的重金属污染,Cd是主要污染因子;苕子和荠菜植株重金属质量比高,且荠菜对重金属的富集能力大于苕子.     

一氧化氮合酶途径参与SO_2胁迫下蚕豆气孔运动调节

以蚕豆为材料,研究一氧化氮合酶(NOS)途径在SO2诱发气孔运动中的作用.研究发现:浓度7.5~200μmol·L-1的SO2衍生物处理后,蚕豆叶面气孔开度减小,气孔开度与SO2衍生物浓度呈负相关;SO2衍生物处理组叶组织中NOS活性增强;加入NO清除剂c-PTIO或NOS抑制剂L-NAME可抑制SO2衍生物诱发的气孔关闭;SO2衍生物处理组保卫细胞内NO和Ca2+水平升高,用c-PTIO降低胞内NO水平后Ca2+水平随之下降.结果表明,SO2衍生物胁迫可诱发保卫细胞内NO合成增加,NO通过调节胞内Ca2+水平升高,激活下游信号转导途径,调节气孔运动;NOS途径介导的NO合成参与了SO2胁迫下蚕豆气孔运动的调节.     

Assessing the economic impact of invasive species: the case of yellow starthistle (Centaurea solsitialis L.) in the rangelands of Idaho, USA

Yellow starthistle (Centaurea solsitialis L.) is an invasive weed that creates problems for the management of Idaho's rangelands. A bioeconomic approach combined with an input-output economic model is used to estimate direct and secondary economic costs of the weed in relation to its interference with agricultural and non-agricultural benefits that rangelands provide. Direct economic costs of the infestations were estimated to be of 8.2 million '05 dollars per year, and secondary costs of 4.5 million '05 dollars per year, for a total of 12.7 million '05 dollars; agricultural related economic impacts accounted for 79% of this total cost, and non-agricultural for 21%.     

金鱼藻与环棱螺对铜绿微囊藻生长及光合活性的抑制作用

沉水植物和螺类是生物防治有害水华的重要手段,然而目前关于这两者对有害蓝藻的协同抑制效率和作用机制尚不清楚.本研究利用沉水植物金鱼藻与铜锈环棱螺在实验室内探究草-螺组合系统对铜绿微囊藻（Microcystis aeruginosa）生长的抑制效果.结果表明,金鱼藻组、 环棱螺组及草-螺组合系统均显著降低了体系内蓝藻Chl-a浓度、总Chl-a浓度和铜绿微囊藻密度,与初始相比,蓝藻活体Chl-a浓度分别减少99.24%、100.00%和98.61%,铜绿微囊藻密度分别减少98.64%、86.44%和97.71%.草-螺共培养和金鱼藻单独培养均可以显著抑制铜绿微囊藻生长,效果相似,而环棱螺单独培养可以使蓝藻Chl-a浓度和光曲线参数值降为零,同时使得微囊藻细胞全部失活.金鱼藻与环棱螺都可以 降低铜绿微囊藻光合活性,草-螺共培养系统可以最大程度降低藻类整体的生长潜能.研究发现,草-螺耦合系统对铜绿微囊藻的总体抑制效率略低于两者单独抑制效率,表明金鱼藻和环棱螺在此过程中存在微弱的拮抗作用,但由于草-螺耦合系统的抑制成效同样显著,且抑制途径 更多样,同时能更好地维持水体营养盐平衡.在实践过程中建议加强沉水植物和螺类的互利共生关系,可以起到更好的抑藻效果.