湖南种子植物重要科属地理分布研究(二)——五味子科

湖南五味子科植物有2属11种2变种,分布于31个县,多生长在海拔600—1200m的山地灌丛或林中。本文依据湖南五味子科植物的地理分布,结合系统分类,植物区系和土壤资料,经分析和推论得知:1.湖南五味子科植物种质资源丰富,以中国特有种为主,它们与毗邻省区的关系密切。2.湖南五味子科植物区系表现为多种区系成分的过渡与汇集,即华南、华东、华中和滇黔桂4个区系成分的交汇、混杂和过渡。3.湖南五味子科植物的多数种类是从湖南以西地区迁移扩散而来,有的种类是从本省西北或西南以外地区而来,极少数植物在本省西南地区及其周边省区分化形成。4.湘西北至湘西南地区是湖南五味子科植物的现代分布中心,现代分化中心是湘西南地区。     

Interactions between nitrate and ammonium uptake: variation with growth rate,nitrogen source and species

The interaction between nitrate and ammonium uptake was examined as a function of preconditioning growth rate and nitrogen source by adding nitrate, ammonium, or both to nitrogen-sufficient,-deficient, and-starvedSkeletonema costatum (Grev.) Cleve and nitrogen-deficientChaetoceros debilis Cleve. By simultaneously measuring the internal accumulation of intermediates of nitrogen assimilation and the rates of nitrogen assimilation, the metabolic control of nitrogen uptake could be assessed. After the simultaneous addition of nitrate and ammonium to culture, both nitrate and ammonium uptake rates were decreased in comparison with the rates observed when each was added alone, although nitrate uptake was usually decreased more than ammonium uptake. Since both nitrate and ammonium uptake rates vary with time, preconditioning growth conditions, nitrogen sources present, and species, it was necessary to use several different indices to quantify inhibition. In general, ammonium inhibition of nitrate uptake inS. costatum was greatest in cultures preconditioned to ammonium and those at low growth rates, whereas ammonium uptake was inhibited most in cultures preconditioned to nitrate. In nitrogen-deficientC. debilis, nitrate uptake was more inhibited by ammonium, but uptake returned to normal rates more quickly than inS. costatum, whereas inhibition of ammonium uptake was similar. These results explain why the interaction between nitrate and ammonium uptake in the field can be so variable. Inhibition of uptake is not controlled by internal ammonium or total amino acids, nor is it related to the inability to reduce nitrate. Instead, inhibition must be determined in part by the external concentration of nitrogen compounds and in part by some intermediate(s) of nitrogen assimilation present inside the cell.Bigelow Laboratory Contribution No. 82022     

北亚热带过渡区土壤的模糊聚类分析

本文阐述了北亚热带过渡区十个土壤剖面的成土条件和基本性质，应用模糊聚类对土壤的五项诊断指标进行了分析，并与发生分类和诊断分类相比较．在中国土壤系统分类中提出建立淋溶土纲和始成土纲的基础上，探讨了供试土壤的分类地位。其中０１－０４号剖面属于典型铁质湿润淋溶上亚类；０５—０７和０９号剖面归为铁质粘磐半干润淋溶土亚类；０８号剖面为典型半干润淡色始成上亚类，１０号剖面为典型淡色滞水淋溶士亚类。     

Biodegradation of quinoline by gel immobilized Burkholderia sp

Burkholderia sp, a gram-negative, rod-shaped, aerobe, capable of degrading quinoline was immobilized in calcium alginate gel beads and used for degradation of quinoline in aqueous solution in the reactor. The optimal conditions for immobilization of the microorganism, such as alginate concentration, calcium ion concentration, initial cell loading, hardening time and bead size, were determined with a view to improving the quinoline degradation rate. The characteristics of quinoline degradation by immobilized microbial cells were investigated. The repeated use of immobilized cells for quinoline degradation was performed and the results revealed that the bioactivity of immobilized cells was stable over 100 h in the repeated batch cultivation for quinoline degradation.     

Thermochemical studies of the toxic actions of heavy metal ions on Rhizopus nigricans

By using a LKB2277 BioActivity Monitor (heat conduction microcalorimeter), stopped-flow method, the thermogenetic curves of Rhizopus nigricans growth at 25 degrees C inhibited by four kinds of heavy metal ions are determined, parameters such as growth rate constants k, inhibitory ratio I, half inhibitory concentration IC50 et al. are obtained. The experimental results show that heavy metal ions can inhibit Rhizopus nigricans growth obviously, low concentration of Cu2+ has promoting action. The inhibitory sequence is Cd2+ > Hg2+ > Pb2+ > Cu2+, half inhibitory concentration of them are Cd+ 0.8 micro g x ml(-1), Hg2+ 1.7 micro g x ml(-1), Pb2+ 48.0 micro g x ml(-1), Cu2+ 110 micro g x ml(-1). This microclorimetric bioassay for acute cellular toxicity is based on metabolic heat evolution from cultured cells. The assay is quantitative, inexpensive, and versatile; moreover, toxicological information can be obtained with cell from other species of interest.     

Dynamics of PCDDs/DFs and coplanar-PCBs in an aquatic food chain of Tokyo Bay

Concentrations and accumulation profiles of PCDDs/DFs and coplanar-PCBs (co-PCBs) in aquatic biota (e.g., plankton, shellfish, benthic invertebrate, and fish) and sediment from Tokyo Bay were examined to elucidate the relationship between bioaccumulation and trophic level in the food web as determined by the stable nitrogen isotope analysis. Bioaccumulation patterns of PCDDs/DFs and co-PCBs varied greatly among congeners. Accumulation patterns of PCDDs/DFs and co-PCBs are not solely explained by their physicochemical properties. Biota-sediment accumulation factors (BSAFs) for co-PCBs in biota from Tokyo Bay were significantly greater than those of PCDDs/DFs. Furthermore, the slopes of the plots of delta15N and BSAF values and water solubility of 2,3,7,8-substituted PCDDs/DFs and co-PCBs were highly correlated. The results of our study would provide the valuable information to understand the accumulation properties of PCDDs/DFs and co-PCBs that can be used as a scientific basis to determine the sediment quality criteria of PCDDs/DFs and co-PCBs.     

Induction of the P450 reporter gene system bioassay by polycyclic aromatic hydrocarbons in Ulsan Bay (South Korea) sediments

Polycyclic aromatic hydrocarbons (PAHs) and induction of the P450 reporter gene system (RGS) for 6- and 16-h exposure periods were determined in organic extracts of Ulsan Bay (South Korea) sediments to assess the utility of this bioassay as a screening tool for PAH contamination. The sum of the concentrations of 23 individual PAHs in 30 sediment samples (sigma PAH) based on GC-MS analysis ranged from 0.05 to 6.1 micrograms/g dry wt. P450 RGS fold induction ranged from 4.0 to 320 micrograms/g based on benzo[a]pyrene toxic equivalents (BaPEq). P450 RGS BaPEq and the 'chemical BaPEq', defined as the sum of the products of individual PAH concentrations and pre-determined toxic equivalency factors, exhibited very strong positive correlations with sigma PAH (r2 > 0.90; P < 0.001). Fold induction did not increase (and in some cases decreased) after the optimal incubation period (6 h) for PAHs, indicating that other compounds known to induce the P450 RGS (e.g. chlorinated organics) were not present at levels effecting significant induction. This was supported by GC-ECD analysis where non-ortho and mono-ortho polychlorinated biphenyls (PCBs) known to be strong P450 RGS inducers were found to be at very low or non-detectable levels in samples with the highest P450 RGS responses. The profound difference in PAH profiles for the two most contaminated sites suggested that this assay is especially sensitive for selected PAHs with greater than four rings. Combined with previous results, the P450 RGS shows promise as a useful screening tool for predicting deleterious biological effects resulting from CYP1A1-inducing, sediment-associated chemicals, particularly high molecular weight PAHs.     

Removal of arsenic(V) from aqueous solutions using iron-oxide-coated modified activated carbon.

Removal of arsenic(V) from aqueous solutions was evaluated with the following three different sorption materials: coal-based activated carbon 12 x 40 (activated carbon), iron(II) oxide (FeO)/activated carbon-H, and iron oxide. The apparent characteristics and physical chemistry performances of these adsorbents were investigated by X-ray diffraction, nitrogen adsorption, and scanning electronic microscope. Also, batch experiments for arsenic removal were performed, and the effects of pH value on arsenic(V) removal were studied. The results suggest that the main phases of the iron oxide surface are magnetite, maghemite, hematite, and goethite; fine and uniform iron oxide particles can cover activated carbon surfaces and affect the surface area or pore structures of activated carbon; adsorption kinetics obey a pseudo-first-order rate equation; and adsorption capacities of adsorbents are affected by the values of pH. The optimum value of pH for iron oxide lies in a narrow range between 4.0 and 5.5, and arsenic(V) removal by FeO/activated carbon-H is ideal and stable in the pH range 3 to 7, while activated carbon has the lowest adsorption capacity in the entire pH range. Also, the adsorption characteristics of FeO/activated carbon-H composites and virgin activated carbon match well the Langmuir adsorption model, while those of iron oxide fit well the Freundlich adsorption model.     

Decolorization of textile wastewater by photo-fenton oxidation technology

This paper describes the use of photo-fenton process for color removal from textile wastewater stream. The wastewater sample to be treated was simulated by using colorless polyvinyl alcohol (PVA) and reactive dyestuff of R94H. As a result, the hydroxyl radical (HO*) oxidation can effectively remove color, but the chemical oxygen demand (COD) was removed in a slight degree. The color removal is markedly related with the amount of HO* formed. The optimum pH for both the OH* formation and color removal occurs at pH 3-5. Up to 96% of color can be removed within 30 min under the studied conditions. Due to the photoreduction of ferric ion into ferrous ion, color resurgence was observed after 30 min. The ferrous dosage and UV power affect the color removal in a positive way, however, the marginal benefit is less significant in the higher range of both. PVA as the major background COD of a textile wastewater stream inhibits the color removal insignificantly as its concentration increases.     

Behaviors of intercellular materials and nutrients in biological nutrient removal process supplied with domestic wastewater and food waste.

A four-stage biological nutrient removal (BNR) process was operated to investigate the effect of anaerobically fermented leachate of food waste (AFLFW) as an external carbon source on nutrient removal from domestic wastewater having a low carbon-to-nitrogen ratio. The BNR system that was supplemented with AFLFW showed a good performance at a sludge retention time (SRT) of 30 days, despite low temperature. With this wastewater, average removal efficiencies of soluble chemical oxygen demand (COD), total nitrogen (T-N), and total phosphorus (T-P) were 88 to 93%, 70 to 74%, and 63 to 68%, respectively. In this study, several kinds of poly-hydroxyalkanoates (PHAs) were observed in cells. These included 24% poly-3-hydroxybutyrate (PHB), 41% poly-3-hydroxyvalerate (PHV), 18% poly-3-hydroxyhexanoate (PHH), 10% poly-3-hydroxyoctanoate (PHO), 5% poly-3-hydroxydecanoate (PHD). and 2% poly-3-hydroxydodecanoate (PHDD), indicating that microorganisms could store various PHAs through the different metabolic pathways. However, breakdown of the enhanced biological phosphorus removal (EBPR) mechanism was observed when SRT increased from 30 to 50 days for the enhancement of nitrification. To study the effect of SRT on EBPR, a sequencing batch reactor (SBR) system that was supplied with glucose was operated at various SRTs of 5, 10, and 15 days. Nitrification and denitrification efficiencies increased as SRT increased. However, the content of intracellular materials such as PHAs, glycogen. and poly-P in cells decreased. From these results, it was concluded that SRT should be carefully controlled to increase nitrification activity and to maintain biological phosphorus removal activity in the BNR process.