Localization of ascorbic acid, ascorbic acid oxidase, and glutathione in roots of Cucurbita maxima L.
To understand the function of ascorbic acid (ASC) in root development, the distribution of ASC, ASC oxidase, and glutathione (GSH) were investigated in cells and tissues of the root apex of Cucubita maxima. ASC was regularly distributed in the cytosol of almost all root cells, with the exception of quiescent centre (QC) cells. ASC also occurred at the surface of the nuclear membrane and correspondingly in the nucleoli. No ASC could be observed in vacuoles. ASC oxidase was detected by immunolocalization mainly in cell walls and vacuoles. This enzyme was particularly abundant in the QC and in differentiating vascular tissues and was absent in lateral root primordia. Administration of the ASC precursor L-galactono-gamma-lactone markedly increased ASC content in all root cells, including the QC. Root treatment with the ASC oxidized product, dehydroascorbic acid (DHA), also increased ASC content, but caused ASC accumulation only in peripheral tissues, where DHA was apparently reduced at the expense of GSH. The different pattern of distribution of ASC in different tissues and cell compartments reflects its possible role in cell metabolism and root morphogenesis.
Liso
Rosalia
R
Dipartimento di Biologia e Patologia Vegetale, Università di Bari, Via E. Orabona 4, I-70125 Bari, Italia.
De Tullio
Mario C
MC
Ciraci
Samantha
S
Balestrini
Raffaella
R
La Rocca
Nicoletta
N
Bruno
Leonardo
L
Chiappetta
Adriana
A
Bitonti
Maria Beatrice
MB
Bonfante
Paola
P
Arrigoni
Oreste
O
D047151:Amaryllidaceae Alkaloids / Q000494:pharmacology; D001204:Ascorbate Oxidase / Q000378:metabolism*; D001205:Ascorbic Acid / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D002473:Cell Wall / Q000378:metabolism; D028464:Cucurbita / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D003683:Dehydroascorbic Acid / Q000494:pharmacology; D005978:Glutathione / Q000378:metabolism*; D010617:Phenanthridines / Q000494:pharmacology; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D036226:Seedlings / Q000378:metabolism; D013400:Sugar Acids / Q000494:pharmacology; D014018:Tissue Distribution; D014617:Vacuoles / Q000378:metabolism
D047151:Amaryllidaceae Alkaloids; D010617:Phenanthridines; D013400:Sugar Acids; C007813:galactonolactone; D001204:Ascorbate Oxidase; D005978:Glutathione; C015330:lycorine; D001205:Ascorbic Acid; D003683:Dehydroascorbic Acid