AbstractPolyamine titers in oat seedlings (Avena sativaL.) were evaluated as possible biomarkers for heavy metal stress. The titers were measured in response to the addition of 20 metal salts. Six of those metal salts were chosen for further study: chromium, cobalt, copper, mercury, nickel, and silver. Changes in polyamine titer in response to the addition of the six metal salts were specific for each metal, but were generally smaller when compared to changes in polyamine titer associated with other forms of plant stress reported in the literature. Changes in putrescine titer, over time, were also specific for each metal, but did not correlate well with the changes in the enzymatic activity of its biosynthetic enzyme, arginine decarboxylase. We conclude that polyamine metabolism and arginine decarboxylase activity are not effective as general biomarkers for evaluating heavy metal stress in oat seedlings.
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