Influence of lead on N03 uptake and reduction in cucumber seedlings

Marek Burzyński, Adam Grabowski

Abstract


The influence of PbCl2 on NO3- uptake and activity level of nitrate (NR) and nitrite MR) reductases in cotyledons and roots of cucumber seedlings was studied. PbCl2 in a 10-5 M concentration decreased by 50 per cent N03 uptake and reduced NR and NiR activity in vivo. In in vitro experiments only high lead concentrations (10-3 M) almost completely inhibited NR activity and reduced by 14-28 per cent that of NiR. Lower lead concentrations which inhibited in vivo NR activity did not affect enzyme induction, but depressed tissue hydration. These results indicate that lead in low concentrations (10-5, 10-4 M) indirectly affected NR and NiR activity by producing water stress and reducing N03- uptake, whereas the direct influence of lead on the proteins of the tested enzymes was noticeable at high concentrations.

Keywords


lead; nitrate reductase; nitrite reductase

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DOI: https://doi.org/10.5586/asbp.1984.009

Journal ISSN:
  • 2083-9480 (online)
  • 0001-6977 (print; ceased since 2016)
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Publisher
Polish Botanical Society