P M Kopittke

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..In addition, we suggest that root border cells possibly contribute to the plant's ability to tolerate excess As(V) by accumulating high levels of As and limiting its movement into the root...

..In addition, Ca was found to alleviate Pb toxicity through a specific effect. Although our data do not preclude site-specific competition (as incorporated in the BLM), we suggest that electrostatic effects have an important role...

..Besides direct toxic effects, osmotic effects or reduced activity of Ca(2+) at the outer surface of the root plasma membrane (and resultant Ca deficiency) may decrease short-term root growth...

..To our knowledge, this is the first report of the in situ distribution and speciation of Cu, Ni, and Zn in hydrated (and fresh) plant tissues, providing valuable information on the potential mechanisms by which they are toxic...

..Although specific effects such as competition are not precluded, the data emphasize the importance of non-specific electrostatic effects in the Mn nutrition of cowpea seedlings over a 1×10(5)-fold range of Mn concentration in solution...

..A multiple regression model related root growth to osmolarity and {I(z)}₀° (R²=0.924), allowing the quantification of their effects...

..This reduction in nodulation with increasing Cu(2+) activity was associated with an inhibition of root hair formation in treatments containing > or =0.77 microM Cu(2+), rather than to a reduction in the size of the Rhizobium population...

..Observing these criteria will potentially lead to reliable data on the relationship between growth depression and the concentration of the toxic metal in solution...

..Due to limited translocation of Cu from the roots to the shoots, phytotoxicity is likely to be more of a problem in remediation of Cu-toxic sites than is Cu toxicity of fauna consuming the above-ground biomass...

..These findings suggest that the ability of signal grass to sequester insoluble Pb in the cell wall represents an additional and potentially important mechanism of Pb tolerance not possessed by the Pb-sensitive Rhodes grass...

..Given the low solubility of Pb-phosphates, nutrient solutions with low P concentrations should be utilized, and plant growth should be related to measured Pb concentrations rather than to the quantity of Pb initially added...

..In the root, Pb was found to accumulate primarily within the cell walls and intercellular spaces...

..01 M CaCl(2) and 0.1 M NaNO(3)) provide the most useful indication of metal phytoavailability across a range of metals of interest, although further research is required...

..The similarity of rupturing effects, despite the difference in strong binding to soft ligands by Ag and to hard ligands by the other metals, suggests a distinctive metabolic effect of Ag that binds only weakly to hard ligands...

..The experiment illustrates the importance of metal interactions with pectin, and the implications of such an interaction in plant metal toxicity and in normal cell wall processes...

..and sunflower ( Helianthus annuus L.) with the Al-specific dye, chrome azurol S (CAS), resulted in the formation of a purple color, with the intensity related to the extent of Al hydrolysis...