Digitale Medien
Oxford, UK
:
Blackwell Publishing Ltd
Physiologia plantarum
59 (1983), S. 0
ISSN:
1399-3054
Quelle:
Blackwell Publishing Journal Backfiles 1879-2005
Thema:
Biologie
Notizen:
Iron-deficient Phaseolus vulgaris L. cv. Prelude developed a high reducing capacity for extracellular Fe(III) at the root surface. This reduction was competitively inhibited by Nitro-Blue Tetrazolium salt (Nitro-BT) which was deposited as a blue precipitate within the epidermis cells of the youngest root parts. Root respiration was not influenced by Nitro-BT. The intracellular reduction of Nitro-BT could largely be prevented by excess extracellular Fe(III)EDTA. Iron-sufficient control plants reduced both extracellular Fe(III)EDTA and intracellular Nitro-BT at a much slower rate. A role of cytosolic NADH or NADPH as direct electron donors for the enhanced Fe(III) reduction at the plasmalemma is indicated. NAD+-3-phosphate dehydrogenase activity was higher in preparations from iron-deficient root parts than in preparations from control root parts. Ferricyanide, dichlorophenolindophenol and phenazine methosulfate were also reduced at an increased rate by iron-deficient roots. We conclude that a trans-plasma membrane electron transfer, mediated by a membrane-bound reductase, is responsible for the reduction of extracellular Fe(III).
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1111/j.1399-3054.1983.tb04223.x
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