Short- and long-term effects of dehydroascorbate in Lupinus albus and Allium cepa roots.
Administration of 1 mM dehydroascorbate (DHA) results in a rapid and large increase in cellular ascorbate (AA) content in both Lupinus albus L. and Allium cepa L. root tips. Uptake of DHA from the medium occurs at a high rate within 10-12 h of incubation, and is slowed down thereafter. In the first few h, DHA reduction to AA is apparently correlated to GSH depletion and slightly higher DHA reductase activity. DHA incubation also seems to induce new GSH synthesis. Longer DHA incubation (24 h) affects root growth by inhibiting cell proliferation. At this stage, an apparently generalised oxidation of SH-containing proteins is observed in DHA-treated roots. Treatment with 1 mM L-galactono-gamma-lactone, the last precursor of AA biosynthesis, results in an increase in AA content similar to that obtained with DHA, but stimulates growth and affects the redox state of SH-containing proteins in the opposite way. A possible multi-step mechanism of DHA reduction/removal is suggested and the hypothesis that DHA inhibits cell cycle progression by affecting the redox state of SH-containing proteins is discussed.
Paciolla
C
C
Dipartimento di Biologia e Patologia Vegetale, Università di Bari, via E. Orabona 4, I-70125 Bari, Italia.
De Tullio
M C
MC
Chiappetta
A
A
Innocenti
A M
AM
Bitonti
M B
MB
Liso
R
R
Arrigoni
O
O
D002455:Cell Division; D003683:Dehydroascorbic Acid / Q000494:pharmacology*; D007887:Fabaceae / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D019803:Glutathione Disulfide / Q000378:metabolism; D005981:Glutathione Synthase / Q000096:biosynthesis; D018519:Meristem / Q000378:metabolism; D019697:Onions / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D010946:Plants, Medicinal; D013936:Thymidine / Q000378:metabolism; D014316:Tritium
D014316:Tritium; D005981:Glutathione Synthase; D019803:Glutathione Disulfide; D013936:Thymidine; D003683:Dehydroascorbic Acid