The Experts below are selected from a list of 171 Experts worldwide ranked by ideXlab platform
Nicholas M Dickinson - One of the best experts on this subject based on the ideXlab platform.
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variability of metal resistance in Acer pseudoplatanus l sycamore callus tissue of different origins
Environmental and Experimental Botany, 1996Co-Authors: Shaun A. Watmough, Nicholas M DickinsonAbstract:Abstract Twenty-eight callus culture cell lines established from shoot tip explants of mature Acer pseudoplatanus L. (sycamore) trees growing at seven metal-contaminated and three uncontaminated sites were screened for metal resistance. Patterns of Cu, Cd and Zn resistance were identified that were related to predicted toxicity of these metals in soils at the sites of origin, adjacent to metal-processing industries and mining spoils. Cell lines established from trees growing at primarily Pb- and Zn-contaminated sites with high soil pH (pH above 6.4) and limited metal bioavailability were no more resistant than those originating from uncontaminated sites. Patterns of metal removal from the media by callus only reflected resistance traits in the case of Ni-resistant cell lines from Zn-contaminated sites, in which callus contained between 30 and 100% less Ni. The results provide evidence that differences exist in patterns of metal resistance in trees according to previous exposure to specific metals. It remains to be understood why traits induced by acclimation are readily expressed in tissue culture and then remain stable in the absence of the toxic metal.
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Induction of zinc and nickel resistance in Acer pseudoplatanus L. (sycamore) callus cell lines
Environmental and Experimental Botany, 1995Co-Authors: Shaun A. Watmough, Christopher C. Gallivan, Nicholas M DickinsonAbstract:Abstract Changes in metal-resistance following pre-exposure to sub-lethal concentrations of Zn or Ni are reported in sycamore ( Acer pseudoplatanus L.) callus cell lines established from shoot explants of mature trees. A cell line derived from a site contaminated primarily by Cu, Cd and Zn possessed a higher resistance to Zn and Ni than did a cell line from an uncontaminated site. Repeated subculturing of both cell lines on 30 mg Zn l −1 and 5 mg Ni l −1 led to respective increases in Zn- and Ni-resistance. Resistance could be induced within an optimum range of media metal concentrations, and there was a clear limit to the level of metal-resistance achievable by induction. There was some evidence of co-resistance betweeen Zn and Ni; selection on 5 mg Ni l −1 did not increase Zn resistance of either cell line but repeated subculturing on 30 mg Zn l −1 considerably enhanced Ni resistance at critical test concentrations.
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survival of Acer pseudoplatanus l sycamore seedlings on metalliferous soils
New Phytologist, 1993Co-Authors: Andrew Turner, Nicholas M DickinsonAbstract:SUMMARY Seeds and seedlings of Acer pseudoplatanus L. (sycamore) were collected at sites contaminated by metals, originating either from mining spoil or from aerial deposition from metal processing industry, and at a number of relatively uncontaminated sites. Seedling growth was examined in relation to site of origin, both in nutrient solutions with elevated metal concentrations and in reciprocal transplant experiments in soils from the sites. Metal tolerance was not detected and there was no significant difference between plants from the different sites of origin. It was found, however, that roots could proliferate in uncontaminated zones of the soil and that, even in contaminated soils, most seedlings used in growth tests survived for at least three years despite impaired growth. Seedlings growing at the contaminated sites showed phytotoxic symptoms associated with high metal levels, but apparently healthy seedlings and saplings of different ages were also found. Some form of low level innate tolerance may be involved but it is suggested that phenotypic plasticity is more important than previously thought, potentially allowing survival until favourable conditions are encountered either temporally or spatially.
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copper tolerance of Acer pseudoplatanus l sycamore in tissue culture
New Phytologist, 1993Co-Authors: Andrew Turner, Nicholas M DickinsonAbstract:SUMMARY The growth of Acer pseudoplatanus L. (sycamore) callus tissue on solid and liquid growth media containing elevated copper concentrations was studied in an attempt to understand the responses of trees to metal contamination and to provide an index of tolerance which may show a parallel expression of tolerance to the whole plant. Callus growth on solid media was very variable, but was significantly reduced at 10 mg l−1, with necrosis occurring at 20 mg l−1; copper was readily removed from the media in direct proportion to its concentration. Cell suspension cultures differed in their response to copper according to their site of origin. In cultures originating from uncontaminated sites, growth was inhibited at 12.5 and 15.0 mg l−1 Cu, but cultures originating from mature trees at a metal-contaminated site were not affected by these concentrations. This metal tolerance trait was stable in cell culture through repeated sub-culturing on uncontaminated media for periods of more than 12 months. The trait was not present in a culture derived from a (non-tolerant) seedling at the metal-contaminated site, but it was induced in one non-tolerant culture by repeated exposure to high metal levels. The significance of these findings is discussed in the context of the possession of appropriate genetic variation in trees for surviving the impact of metal contamination.
P Lado - One of the best experts on this subject based on the ideXlab platform.
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Effect of penconazole and flusilazol on the tonoplast of Acer pseudoplatanus cells
Plant Science, 2003Co-Authors: Roberta Colombo, Raffaella Cerana, P LadoAbstract:Abstract Recent data showed that some triazole fungicides affect plasma membrane functionality in higher plants. In this paper, we studied the effect of two triazoles, penconazole and flusilazol, on the vacuolar membrane in Acer pseudoplatanus cultured cells. These substances from 0.1 mM concentration induced a reduction of the volume of the vacuoles in situ and from 0.05 mM concentration a lysis of the isolated vacuoles and an inhibition of two tonoplast enzyme activities, the nitrate-sensitive H + -ATPase and the K + -stimulated pyrophosphatase. These results indicate that penconazole and flusilazol can directly affect the vacuolar membrane, independently of their activity on biosynthetic metabolism.
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enhanced k stimulated pyrophosphatase activity in nacl adapted cells of Acer pseudoplatanus
Physiologia Plantarum, 1994Co-Authors: Luisa Zingarelli, Paola Anzani, P LadoAbstract:Cell suspension cultures of Acer pseudoplatanus L. (Bligny cell line) adapted to growth in the presence of NaCl, are a useful tool for investigating mechanisms for cellular salt tolerance. We compared the activities of vanadate-sensitive (plasma membrane) and nitrate-sensitive (tonoplast) ATPases, and tonoplast K + -stimulated PPase in microsomal fractions (8 000-108 000 g) from unadapted and NaCl-adapted (80 mM) cells of A. pseudoplatanus
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Enhanced K^+-stimulated pyrophosphatase activity in NaCl-adapted cells of Acer pseudoplatanus
Physiologia Plantarum, 1994Co-Authors: Luisa Zingarelli, Paola Anzani, P LadoAbstract:Cell suspension cultures of Acer pseudoplatanus L. (Bligny cell line) adapted to growth in the presence of NaCl, are a useful tool for investigating mechanisms for cellular salt tolerance. We compared the activities of vanadate-sensitive (plasma membrane) and nitrate-sensitive (tonoplast) ATPases, and tonoplast K + -stimulated PPase in microsomal fractions (8 000-108 000 g) from unadapted and NaCl-adapted (80 mM) cells of A. pseudoplatanus
Shaun A. Watmough - One of the best experts on this subject based on the ideXlab platform.
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variability of metal resistance in Acer pseudoplatanus l sycamore callus tissue of different origins
Environmental and Experimental Botany, 1996Co-Authors: Shaun A. Watmough, Nicholas M DickinsonAbstract:Abstract Twenty-eight callus culture cell lines established from shoot tip explants of mature Acer pseudoplatanus L. (sycamore) trees growing at seven metal-contaminated and three uncontaminated sites were screened for metal resistance. Patterns of Cu, Cd and Zn resistance were identified that were related to predicted toxicity of these metals in soils at the sites of origin, adjacent to metal-processing industries and mining spoils. Cell lines established from trees growing at primarily Pb- and Zn-contaminated sites with high soil pH (pH above 6.4) and limited metal bioavailability were no more resistant than those originating from uncontaminated sites. Patterns of metal removal from the media by callus only reflected resistance traits in the case of Ni-resistant cell lines from Zn-contaminated sites, in which callus contained between 30 and 100% less Ni. The results provide evidence that differences exist in patterns of metal resistance in trees according to previous exposure to specific metals. It remains to be understood why traits induced by acclimation are readily expressed in tissue culture and then remain stable in the absence of the toxic metal.
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Induction of zinc and nickel resistance in Acer pseudoplatanus L. (sycamore) callus cell lines
Environmental and Experimental Botany, 1995Co-Authors: Shaun A. Watmough, Christopher C. Gallivan, Nicholas M DickinsonAbstract:Abstract Changes in metal-resistance following pre-exposure to sub-lethal concentrations of Zn or Ni are reported in sycamore ( Acer pseudoplatanus L.) callus cell lines established from shoot explants of mature trees. A cell line derived from a site contaminated primarily by Cu, Cd and Zn possessed a higher resistance to Zn and Ni than did a cell line from an uncontaminated site. Repeated subculturing of both cell lines on 30 mg Zn l −1 and 5 mg Ni l −1 led to respective increases in Zn- and Ni-resistance. Resistance could be induced within an optimum range of media metal concentrations, and there was a clear limit to the level of metal-resistance achievable by induction. There was some evidence of co-resistance betweeen Zn and Ni; selection on 5 mg Ni l −1 did not increase Zn resistance of either cell line but repeated subculturing on 30 mg Zn l −1 considerably enhanced Ni resistance at critical test concentrations.
J Grace - One of the best experts on this subject based on the ideXlab platform.
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acclimation to drought in Acer pseudoplatanus l sycamore seedlings
Journal of Experimental Botany, 1992Co-Authors: Ayoub A M Khalil, J GraceAbstract:A glasshouse experiment was conducted with well-watered and water-stressed seedlings of sycamore (Acer pseudoplatanus L.) grown in soil columns. Water was withheld when the seedlings were 82-d-old. Effects of soil drying on stomatal behaviour, water relations, xylem cavitation, and growth of leaves and roots were evaluated. Stomatal conductance declined well before any observable change in bulk leaf water potentials, and was correlated with soil water status. At seven weeks, osmotic potential had declined by 0.51 MPa and 0.44 MPa at full and zero turgor, respectively
Andrew Turner - One of the best experts on this subject based on the ideXlab platform.
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survival of Acer pseudoplatanus l sycamore seedlings on metalliferous soils
New Phytologist, 1993Co-Authors: Andrew Turner, Nicholas M DickinsonAbstract:SUMMARY Seeds and seedlings of Acer pseudoplatanus L. (sycamore) were collected at sites contaminated by metals, originating either from mining spoil or from aerial deposition from metal processing industry, and at a number of relatively uncontaminated sites. Seedling growth was examined in relation to site of origin, both in nutrient solutions with elevated metal concentrations and in reciprocal transplant experiments in soils from the sites. Metal tolerance was not detected and there was no significant difference between plants from the different sites of origin. It was found, however, that roots could proliferate in uncontaminated zones of the soil and that, even in contaminated soils, most seedlings used in growth tests survived for at least three years despite impaired growth. Seedlings growing at the contaminated sites showed phytotoxic symptoms associated with high metal levels, but apparently healthy seedlings and saplings of different ages were also found. Some form of low level innate tolerance may be involved but it is suggested that phenotypic plasticity is more important than previously thought, potentially allowing survival until favourable conditions are encountered either temporally or spatially.
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copper tolerance of Acer pseudoplatanus l sycamore in tissue culture
New Phytologist, 1993Co-Authors: Andrew Turner, Nicholas M DickinsonAbstract:SUMMARY The growth of Acer pseudoplatanus L. (sycamore) callus tissue on solid and liquid growth media containing elevated copper concentrations was studied in an attempt to understand the responses of trees to metal contamination and to provide an index of tolerance which may show a parallel expression of tolerance to the whole plant. Callus growth on solid media was very variable, but was significantly reduced at 10 mg l−1, with necrosis occurring at 20 mg l−1; copper was readily removed from the media in direct proportion to its concentration. Cell suspension cultures differed in their response to copper according to their site of origin. In cultures originating from uncontaminated sites, growth was inhibited at 12.5 and 15.0 mg l−1 Cu, but cultures originating from mature trees at a metal-contaminated site were not affected by these concentrations. This metal tolerance trait was stable in cell culture through repeated sub-culturing on uncontaminated media for periods of more than 12 months. The trait was not present in a culture derived from a (non-tolerant) seedling at the metal-contaminated site, but it was induced in one non-tolerant culture by repeated exposure to high metal levels. The significance of these findings is discussed in the context of the possession of appropriate genetic variation in trees for surviving the impact of metal contamination.
