Template-Type: ReDIF-Article 1.0 Author-Name: J. Dong Author-Workplace-Name: Department of Agronomy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, P.R. China Author-Name: W.H. Mao Author-Workplace-Name: Department of Agronomy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, P.R. China Author-Workplace-Name: Center of Analysis and Measurement, Zhejiang University, Hangzhou, P.R. China Author-Name: G.P. Zhang Author-Workplace-Name: Department of Agronomy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, P.R. China Author-Name: F.B. WU Author-Workplace-Name: Department of Agronomy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, P.R. China Author-Name: Y. Cai Author-Workplace-Name: Department of Agronomy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, P.R. China Title: Root excretion and plant tolerance to cadmium toxicity - a review Abstract: Significant quantities of Cd have been added to soils globally due to various anthropogenic activities, posing a serious threat to safe food production and human health. Rhizosphere, as an important interface of soil and plant, plays a significant role in the agro-environmental system. This article presents a review of relationship between root excretion and microorganisms and plant resistance to Cd toxicity and possible mechanisms. Root exudates markedly altered in species and quantity under Cd stress. Root exudates can affect Cd absorption by plants through changing the physical and chemical characteristics of rhizospheres. The influence of root exudates on Cd bioavailability and toxicity may include modifying the rhizosphere pH and Eh, chelating/complexing and depositing with Cd ions, and altering the community construction, the numbers and activities of rhizospheric microbes. In this paper, the methods to reduce the transfer of Cd in soil-plant system by adjusting rhizosphere environment are discussed, and some aspects are also proposed that should be emphasized in the future research work. Keywords: bioavailability, cadmium, microorganisms, rhizosphere, root excretion Journal: Plant, Soil and Environment Pages: 193-200 Volume: 53 Issue: 5 Year: 2007 DOI: 10.17221/2205-PSE File-URL: http://pse.agriculturejournals.cz/doi/10.17221/2205-PSE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/pse-200705-0001.txt Handle: RePEc:caa:jnlpse:v:53:y:2007:i:5:id:2205-PSE Template-Type: ReDIF-Article 1.0 Author-Name: D. Pavlíková Author-Workplace-Name: Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Czech Republic Author-Name: M. Pavlík Author-Workplace-Name: Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Prague, Czech Republic Author-Name: L. Staszková Author-Workplace-Name: Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Czech Republic Author-Name: P. Tlustoš Author-Workplace-Name: Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Czech Republic Author-Name: J. Száková Author-Workplace-Name: Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Czech Republic Author-Name: J. Balík Author-Workplace-Name: Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Czech Republic Title: The effect of potentially toxic elements and sewage sludge on the activity of regulatory enzyme glutamate kinase Abstract: The glutamate kinase activity was investigated as a plant stress response to Cd, Zn, As or sewage sludge application to soil in the pot and field experiments with spinach (Spinacia oleracea L.). Allosteric regulation of glutamate kinase activity by free proline creates a possibility for an increase in glutamic acid content due to the synthesis of glutathione and phytochelatines in plant cells. For this reason the high rates of As, Cd and Zn applied into soil strongly decreased the glutamate kinase activity. Allosteric regulation of the glutamate kinase activity did not inhibit the synthesis of proline and hydroxyproline under stress condition caused by organic pollutants after application of sewage sludge. Formed proline was bound to stress proteins and therefore glutamate kinase activity was not inhibited. Keywords: proline regulation, toxic elements, plant stress metabolism, chronic stress Journal: Plant, Soil and Environment Pages: 201-206 Volume: 53 Issue: 5 Year: 2007 DOI: 10.17221/2204-PSE File-URL: http://pse.agriculturejournals.cz/doi/10.17221/2204-PSE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/pse-200705-0002.txt Handle: RePEc:caa:jnlpse:v:53:y:2007:i:5:id:2204-PSE Template-Type: ReDIF-Article 1.0 Author-Name: R. Hajiboland Author-Workplace-Name: Plant Science Department, University of Tabriz, Iran Author-Name: L. Amjad Author-Workplace-Name: Plant Science Department, University of Tabriz, Iran Title: Does antioxidant capacity of leaves play a role in growth response to selenium at different sulfur nutritional status? Abstract: There are evidences of beneficial effects of selenium (Se) on plant growth. In this work, using alfalfa (Medicago sativa L.) and two varieties of Brassica oleracea L. (cabbage and kohlrabi), the effect of Se addition (10 and 20μM) on growth and concentration of sulfur and Se was investigated in hydroponic experiments. In order to study the involvement of Se-mediated changes in the antioxidant capacity of plants in growth promotion by Se, the activity of antioxidant enzymes including ascorbate peroxidase (APX), catalase (CAT), peroxidase (POD), superoxide dismutase (SOD) and glutathione reductase (GR) and the concentration of H2O2 and glutathione were determined. It was demonstrated that sulfur sufficient cabbage and kohlrabi plants concomitant with growth stimulation in response to Se addition expressed a progressive oxidative stress as judged by a lower activity of antioxidant enzymes and accumulation of oxidants. Results imply that the function of antioxidant system of plants could not explain either the growth stimulatory effect of Se in cabbage and kohlrabi or different response of alfalfa plants to Se supplementation. Keywords: antioxidant system, Brassica oleracea L., Medicago sativa L., Se supplementation Journal: Plant, Soil and Environment Pages: 207-215 Volume: 53 Issue: 5 Year: 2007 DOI: 10.17221/2202-PSE File-URL: http://pse.agriculturejournals.cz/doi/10.17221/2202-PSE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/pse-200705-0003.txt Handle: RePEc:caa:jnlpse:v:53:y:2007:i:5:id:2202-PSE Template-Type: ReDIF-Article 1.0 Author-Name: M. Komárek Author-Workplace-Name: Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Czech Republic Author-Name: P. Tlustoš Author-Workplace-Name: Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Czech Republic Author-Name: J. Száková Author-Workplace-Name: Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Czech Republic Author-Name: V. Chrastný Author-Workplace-Name: Faculty of Agriculture, University of South Bohemia, České Budějovice, Czech Republic Author-Name: J. Balík Author-Workplace-Name: Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Czech Republic Title: The role of Fe- and Mn-oxides during EDTA-enhanced phytoextraction of heavy metals Abstract: In several cases ethylenediaminetetraacetic acid (EDTA) proved to be an efficient mobilising amendment during chemically enhanced phytoextraction of heavy metals. The presence of Fe-(hydr)oxides and their dissolution after the addition of EDTA can limit the phytoextraction of the targeted heavy metals due to the high stability of the formed Fe(III)EDTA complexes. This study has focused on the influence of Fe- and Mn-oxides and hydroxides dissolution on heavy metal uptake by Zea mays in a two-year EDTA-enhanced phytoextraction process. Incubation experiments and speciation modelling proved the increased concentrations of Mn and Fe through the dissolution of Mn-and Fe-(hydr)oxides. Furthermore, increased Fe and Mn accumulation was observed in maize plants after the second year of the phytoextraction process. Therefore, the presence of Mn- and especially Fe-(hydr)oxides proved to be a limiting factor during EDTA-enhanced phytoextraction of heavy metals from contaminated soils. Keywords: EDTA, phytoextraction, Fe oxides, Mn oxides, heavy metals, Zea mays Journal: Plant, Soil and Environment Pages: 216-224 Volume: 53 Issue: 5 Year: 2007 DOI: 10.17221/2203-PSE File-URL: http://pse.agriculturejournals.cz/doi/10.17221/2203-PSE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/pse-200705-0004.txt Handle: RePEc:caa:jnlpse:v:53:y:2007:i:5:id:2203-PSE Template-Type: ReDIF-Article 1.0 Author-Name: N. Finžgar Author-Workplace-Name: BiotechnicalFaculty, University of Ljubljana, Slovenia Author-Name: P. Tlustoš Author-Workplace-Name: Facultyof Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Czech Republic Author-Name: D. Leštan Author-Workplace-Name: BiotechnicalFaculty, University of Ljubljana, Slovenia Title: Relationship of soil properties to fractionation, bioavailability and mobility of lead and zinc in soil Abstract: Sequential extractions, metal uptake by Taraxacum officinale, Ruby's physiologically based extraction test (PBET) and toxicity characteristic leaching procedure (TCLP), were used to assess the risk of Pb and Zn in contaminated soils, and to determine relationships among soil characteristics, heavy metals soil fractionation, bioavailability and leachability. Regression analysis using linear and 2nd order polynomial models indicated relationships between Pb and Zn contamination and soil properties, although of small significance (P < 0.05). Statistically highly significant correlations (P < 0.001) were obtained using multiple regression analysis. A correlation between soil cation exchange capacity (CEC) and soil organic matter and clay content was expected. The proportion of Pb in the PBET intestinal phase correlated with total soil Pb and Pb bound to soil oxides and the organic matter fraction. The leachable Pb, extracted with TCLP, correlated with the Pb bound to carbonates and soil organic matter content (R2 = 69%). No highly significant correlations (P < 0.001) for Zn with soil properties or Zn fractionation were obtained using multiple regression. Keywords: soil contamination, soil characteristics, potentially toxic metals, risk assessment Journal: Plant, Soil and Environment Pages: 225-238 Volume: 53 Issue: 5 Year: 2007 DOI: 10.17221/2201-PSE File-URL: http://pse.agriculturejournals.cz/doi/10.17221/2201-PSE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/pse-200705-0005.txt Handle: RePEc:caa:jnlpse:v:53:y:2007:i:5:id:2201-PSE