Phytotoxic activity of crop residues from Burdock and an active substance

Abstract

Problems related to weed management such as outbreaks of herbicide-resistant weeds have recently increased. An interesting approach to such problems is to use plant materials with phytotoxic activity. Burdock (Arctium lappa L.) is a biennial herb belonging to Asteraceae and is cultivated in several countries. The present study investigated the phytotoxic activity of burdock and its active substances. Extracts of both burdock leaves and roots inhibited the shoot and root growth of cress and barnyard grass, where the level of inhibition increased with increasing extract concentration. The leaf extracts had 2.0–2.5 times higher activity than the root extracts. Bioassay-guided separations of the leaf extracts led to isolation of a phytotoxic substance, onopordopicrin. Onopordopicrin significantly inhibited the shoot and root growth of cress and barnyard grass. The concentrations of the substance required for 50% growth inhibition were 0.27 and 0.26?mM for cress shoots and roots, respectively, and 1.86 and 0.35?mM for barnyard grass shoots and roots, respectively. The present results suggest that burdock leaves have high phytotoxic activity and onopordopicrin may play a major role in the activity. Burdock leaves may be a good resource for weed management.     

零价铁复合有机膨润土处理染料废水的研究

针对目前印染废水处理现状及膨润土在水处理中回收困难等问题,提出将零价铁复合到有机膨润土中制成零价铁复合有机膨润土(ZVI-OB),以达到高效吸附并降解污染物的目的。以染料废水(Orange II) 作为研究对象,考察了废水中染料的初始浓度、pH以及吸附时间对ZVI-OB去除染料效率的影响,并研究了吸附后降解过程中时间和pH对污染物降解的影响以及降解前后膨润土层结构的变化。研究结果表明,ZVI-OB相对于CTMAB改性的有机膨润土而言,其吸附量有所降低,但ZVI-OB在吸附污染物之后能有效降解有机物。ZVI-OB在饱和吸附Orange II后经催化氧化,总有机碳含量降低为原来的19%,可以重复利用。     

零价铁与厌氧微生物协同还原地下水中的硝基苯

通过间歇式实验,考察了零价铁与厌氧微生物协同还原地下水中硝基苯的效果。实验结果表明,由零价铁腐蚀为厌氧微生物提供H2电子供体还原硝基苯的效果明显优于零价铁和微生物单独作用,硝基苯去除率分别提高21.8%和57.0%。弱酸性条件有利于协同反应进行,当初始pH为5.0和6.0时,4 d后硝基苯去除率比初始pH为7.0时的提高74.4%和35.2%。增加零价铁投加量可提高协同还原的效果,零价铁最佳投加量为250 mg/L。零价铁腐蚀产生的Fe2+无法作为电子供体被微生物利用,但可作为无机营养元素促进协同过程。由于零价铁产H2速率受表面覆盖物影响不明显,在地下水修复过程中可保证协同效果并延长零价铁的使用寿命。     

几种印染助剂对壳聚糖稳定纳米铁去除酸性品红的影响

以氯化铁为铁源,硼氢化钠为还原剂,壳聚糖为稳定剂,采用液相还原法制备壳聚糖稳定纳米铁（CS-nZⅥ）;研究了印染废水中常见助剂NaNO₃、Na₂SO₄、NaH₂PO₄、K₂Cr₂O₇、EDTA二钠盐存在下,超声波辅助CS-nZⅥ对酸性品红（AF）降解的影响。结果表明,反应15 min,0.01 g CS-nZⅥ对25 mL、100 mg/L AF的去除率高达99.9%;各种助剂的存在使得纳米铁表面不同程度失活,阻碍反应的进行,使得AF的去除率下降。NaNO₃、K₂Cr₂O₇、EDTA二钠盐与纳米铁发生反应,与AF存在明显的竞争作用。重复利用实验表明,CS-nZⅥ重复利用7次仍具有一定的反应活性。此外,CS-nZⅥ对加标（50 mg/L）实际废水中AF的去除率达到99%以上,表明CS-nZⅥ是一种潜在的环境修复材料。     

Effects of economic growth on biodiversity in the United States

For many citizens and policymakers, the empirical relationship between economic growth and biodiversity conservation has not been sufficiently established for purposes of identifying the types of economic policies amenable to biodiversity conservation. Some think economic growth conflicts with biodiversity conservation; others think economic growth conduces biodiversity conservation. With panel data from 1997‐2011, encompassing US continental states, we developed a series of statistical models to investigate the relationships among species endangerment, human population, and economic growth as indicated by GDP and per capita GDP. Species endangerment is highly correlated with population and GDP, and per capita GDP is a significant regressor of species endangerment. Across US continental states, competitive exclusion of non‐human species occurs via human economic growth and population growth.     

甘肃省第三产业对经济增长贡献的实证研究

第三产业的加快发展是生产力提高和社会进步的必然结果。大力发展第三产业有利于提高工农业生产的社会化和专业化水平,有利于优化生产结构,促进市场充分发育,缓解就业压力,从而促进整个经济持续、快速和健康发展。利用1991-2009年数据,以向量自回归模型为基础,采用单位根检验、协整分析和格兰杰因果检验等方法对甘肃省第三产业与经济增长之间的关系进行了实证研究。结果表明,1991-2009年甘肃省第三产业总值对GDP的长期弹性为0．35035,第三产业对经济增长具有积极的促进作用。     

Assessing benzene-induced toxicity on wild type Euglena gracilis Z and its mutant strain SMZ

Benzene is a representative member of volatile organic compounds and has been widely used as an industrial solvent. Groundwater contamination of benzene may pose risks to human health and ecosystems. Detection of benzene in the groundwater using chemical analysis is expensive and time consuming. In addition, biological responses to environmental exposures are uninformative using such analysis. Therefore, the aim of this study was to employ a microorganism, Euglena gracilis (E. gracilis) as a putative model to monitor the contamination of benzene in groundwater. To this end, we examined the wild type of E. gracilis Z and its mutant form, SMZ in their growth rate, morphology, chlorophyll content, formation of reactive oxygen species (ROS) and DNA damage in response to benzene exposure. The results showed that benzene inhibited cell growth in a dose response manner up to 48 h of exposure. SMZ showed a greater sensitivity compared to Z in response to benzene exposure. The difference was more evident at lower concentrations of benzene (0.005–5 μM) where growth inhibition occurred in SMZ but not in Z cells. We found that benzene induced morphological changes, formation of lipofuscin, and decreased chlorophyll content in Z strain in a dose response manner. No significant differences were found between the two strains in ROS formation and DNA damage by benzene at concentrations affecting cell growth. Based on these results, we conclude that E. gracilis cells were sensitive to benzene-induced toxicities for certain endpoints such as cell growth rate, morphological change, depletion of chlorophyll. Therefore, it is a potentially suitable model for monitoring the contamination of benzene and its effects in the groundwater.     

2种新分离微藻的生长、氮磷去除和营养特性的比较研究

为了解2种新分离微藻的净化和资源化潜力,研究比较了其生长、氮磷去除和营养特性。结果表明,栅藻和月牙藻的最大生物量（干重）分别为0．78g／L和0．53g／L;最大生物量（干重）增长速率分别为0．05g／（L·d）和0．03g／（L·d）。培养至第23天,栅藻和月牙藻对TN的去除率分别为85．1％和72．5％;对TP的去除率为82．6％和79．7％,但栅藻较月牙藻更易释放较多的No2--N进入藻液。稳定期时,栅藻、月牙藻的粗蛋白质含量和粗蛋白产量（干重）分别为31．8％、19．2％和0．24g／L、0．09g／L;粗脂含量和粗脂产量（干重）分别为7．81％、9．26％和0．06g／L、0．05g／L。综上,与月牙藻相比,栅藻具有明显的生长、氮磷去除和营养优势,在进行水产养殖废水的净化和资源化利用上可作为优选藻种。     

Changing effluent chemistry affect survival,growth and physiological function of <Emphasis Type="Italic">Acacia nilotica</Emphasis> seedlings in northwestern region of India

Recycling and conservation efforts for water are the need of the day because of the lack of new water sources and the ever-increasing demand for drinking water. Seedlings of Acacia nilotica L. were irrigated with: canal water (T₁, control); municipal effluent (T₂); textile effluent (T₃); steel effluent (T₄); textile + municipal effluent in 1:1 ratio (T₅); steel + municipal effluent in 1:2 ratio (T₆); steel + textile in 1:2 ratio (T₈) and steel + municipal + textile in 1:2:2 ratio (T₇) with views to observe effluents effect on the seedlings and its adaptability and to recommend safe disposal of these effluents. Seedlings in T₆, T₇ and T₈ showed 50% lesser height and collar diameter than those in control. Seedlings in T₂ attained greatest height, collar diameter, numbers of branches and produced 140 g dry biomass seedling⁻¹. Highest concentration of manganese (Mn), iron (Fe), copper (Cu) and zinc (Zn) and lowest concentration of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg) in the seedlings of T₄, T₆, T₇ and T₈ resulted in nutritional imbalance, mineral toxicity and reduction in photosynthetic (Pn) and transpiration (E) rates and caused seedling mortality. Seedlings of T₃ had highest sodium concentration and low concentration of Ca, Mg and micronutrients resulting in nutritional imbalance, augmented chlorosis and reduced gas exchange and biomass by half as compared to control. Increased growth, Pn and E and biomass in seedlings of T₅ over T₃ and survival period in T₆, T₇ and T₈ seedlings suggested a beneficial effect of effluents mixing. Unscientific disposal should be avoided and toxic concentration of metal ions␣may be reduced for long-term application and harmless disposal of effluents in afforestation and urban development.     

Europe’s energy deficit: a population dilemma

Europe’s growing energy deficit and destabilising climate may lead the EU and its constituent member states to change its attitude to population size and growth.