ISSN:1522-6514    

DOI:10.1080/15226519908500008

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

ISSN:1522-6514    

DOI:10.1080/15226519908500009

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Willow is shown to be able to accumulate high levels of heavy metal ions such as cadmium and zinc. The properties of willow to be used in phytoextraction therefore have been studied. In this article, results from different studies on heavy metals and willow have been used to demonstrate the capacity and possibility of usingSalixin phytoextraction.

ISSN:1522-6514    

DOI:10.1080/15226519908500010

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Phytoremediation is a relatively new technology, whose practical application still requires more studies in various fields, including biology, sociology, legislation, and education. In order to establish a phytoremediation site, it is necessary that: (1) no detrimental effects are transferred to the surrounding environment, (2) the management of the site is effective from an economical and social point of view, and (3) the overall strategy is economically advantageous over other techniques. Waste management and treatment have a great social and psychological impact. Therefore, the public acceptance of phytoremediation application also depends on appropriate measures taken to inform people about the advantages and safety of this technology. Another very important aspect is the regulatory acceptance of phytoremediation as a valid alternative to other remediation or decontamination strategies. In this case the safety of the procedure utilized and the absence of environmental impacts is mandatory. In order to integrate these different aspects with modern strategies for phytoremediation, it is important that scientists, economists, lawyers, and managers from public and private agencies and institutions are able to share their own needs, experiences, and results. PHYTONET is a thematic network created with the purpose of addressing all of these issues and links with other networks operating on similar or complementary subjects.

ISSN:1522-6514    

DOI:10.1080/15226519908500011

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Hybrid poplar trees were exposed to eleven organic compounds in hydroponic systems. The eleven contaminants were common pollutants with a wide range of physio-chemical properties such as the octanol-water partition coefficient, Henry's constant, vapor pressure, and molecular weight. Contaminants,14C-labeled, were introduced into the root zone, and contaminant transport and fate were examined. Aqueous concentrations were monitored throughout each experiment as was vapor phase concentrations in the air stream passing over the leaves. At experiment conclusion, plant tissues were oxidized to determine14C concentrations. The uptake, distribution, and volatilization of these contaminants varied greatly among the 11 contaminants in the study. Uptake and translocation of the contaminants ranged from < 0.3% (of the applied14C-labeled compound) for 1,2,4-trichlorobenzene to 20% for benzene. Volatile compounds were volatilized from the leaves. Volatilization in the transpiration stream was related to the vapor pressure of the compound. The fate and transport mechanisms investigated in this study provide valuable insight into the potential fate of contaminants in full-scale phytoremediation.

ISSN:1522-6514    

DOI:10.1080/15226519908500012

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Fourteen ecotypes ofArabidopsis thalianawere grown on agar, containing up to 40 μMHgCl2. Two groups could be identified: (1) sensitive ecotypes growing only up to 30 μMand (2) tolerant ecotypes growing at 40 μM. The tolerant ecotypes accumulated up to 100 mg mercury/kg fresh weight in their rosettes.Arabidopsis thalianawild-type Columbia (Col-wt) was analyzed in more detail and showed an exponential mercury accumulation with increasing Hg2+-concentrations in the medium. Increasing Hg2+-concentrations resulted in a delayed growth of the plants. The roundish shape of the leaves changed to a more elongated form, and the leaf color changed from dark green to bright green. Hg2+-induced transcripts of several genes known to be induced by oxidative stress were measured and compared with the induction by ozone and UV-B. Glutathione-S-transferase (GST1) and several pathogenesis-related protein (PR) mRNAs were not induced in plants grown on Hg2+-containing medium. However, ozone fumigation increased the level of all these transcripts transiently. Similarly, UV-B irradiation resulted only in a weak mRNA increase. Metallothionein 1a (MT1a) transcript accumulation increased with rising Hg2+-concentrations, whereas MT2a mRNA level was unchanged. In contrast, MT2a transcripts were induced by ozone, whereas MT1a transcripts were unaffected. UV-B irradiation had a weak effect on MT1a and no effect on MT2a transcripts. These results indicate that different abiotic stressors led to differential transcript changes ofArabidopsis thaliana.

ISSN:1522-6514    

DOI:10.1080/15226519908500013

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Different analytical techniques were applied to describe the localization of lead and chromium in the tissues of walnut (Juglans regia) and maple (Acer saccharinum) plants exposed to soils that had been artificially contaminated with heavy metals. Two X-ray-based techniques, synchrotron radiation X-ray fluorescence (μ-SRXF) and X-ray microanalysis (SEM/EDX), were utilized in association with induced coupled plasma optical emission spectrometry (ICP-OES). These techniques allowed the definition of maps showing a preferential accumulation of lead in the root periderm of both plants and a limited translocation of the metal to the stems. Accordingly, estimation of the lead concentration with ICP-OES showed that roots contained, on a dry weight basis, 20 to 40 times more metal than stems. Chromium, supplied to the plants as Cr3+or Cr6+, was taken up only in the latter case and in limited amounts. In general, walnut was more efficient than maple in the uptake of lead and chromium. The combination of X-ray-based techniques and ICP-OES proved to be a powerful quantitative tool in mapping, with high definition, the sites of metal storage in plant tissues.

ISSN:1522-6514    

DOI:10.1080/15226519908500014

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The proposed phytoremediation technique is based on the successful exploitation and optimization of oxidative coupling, mediated by horseradish peroxidase. Susceptibility to degradation of a selection of phenolic compounds, in solution, by horseradish peroxidase appears to be structurally related and was found to be of the order 2,4-dichlorophenol (2,4-DCP) > 4-chlorophenol (4-CP) > 2-chlorophenol (2-CP). Only 1.89% of 2,4-DCP, at an initial concentration of 5 mM, remained unchanged at the end of the experiment. Reaction rates between purified horseradish peroxidase and 2,4-DCP were found to be extremely rapid with 74% of the substrate removed from solution during the first 30 s. Inhibition of the reaction by the heavy metals Cd, Zn, Ni, and Pb at concentrations of 100 mg/l is of concern because these metals are often present in contaminated soils. H2O2has a dominant role in optimizing peroxidase activity in crude horseradish extracts. Fluctuations in temperature and pH, normally experienced in soils, did not appear to have a detrimental impact on peroxidase activity. However, the functioning of the enzyme is seriously affected at a pH ≤ 3. All reactions in this study were carried out in solution.

ISSN:1522-6514    

DOI:10.1080/15226519908500015

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor