Role of apoplastic and cell-wall peroxidases on the stimulation of root elongation by ascorbate

Elongation of onion (Allium cepa L.) roots was highly stimulated by ascorbate (ASC) and its natural precursor I-galactone-gamma-lactone (GL). When incubation media were supplemented with lycorine (Lyc), an inhibitor of the ASC biosynthesis, root growth was negligible even in the presence of ASC or G...

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Bibliographic Details
Published in:Plant physiology (Bethesda) 1996-11, Vol.112 (3), p.1119-1125
Main Authors: Cordoba-Pedregosa, M. del C. (Universidad de Cordoba, Cordoba, Spain.), Gonzalez-Reyes, J.A, Canadillas, M. del, Navas, P, Cordoba, F
Format: Article
Language:English
Subjects:
ACIDE ASCORBIQUE
ACIDO ASCORBICO
ACTIVIDAD ENZIMATICA
ACTIVITE ENZYMATIQUE
ALCALOIDE
ALCALOIDES
ALLIUM CEPA
ANTIMETABOLITE
ANTIMETABOLITOS
Biological and medical sciences
Cell growth
Cell membranes
Cell walls
CELLULE
CELULAS
Chemical agents
CITOPLASMA
COMPOSE PHENOLIQUE
COMPUESTOS FENOLICOS
CRECIMIENTO
CROISSANCE
CYTOPLASME
Development and Growth Regulation
Free radicals
Fundamental and applied biological sciences. Psychology
Onions
PARED CELULAR
PAROI CELLULAIRE
PEROXIDASAS
PEROXYDASE
Phosphates
Plant cells
Plant physiology and development
Plant roots
Plants
RACINE
RADICAL LIBRE
RADICALES LIBRES
RAICES
Root growth
Vegetative apparatus, growth and morphogenesis. Senescence
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Summary:Elongation of onion (Allium cepa L.) roots was highly stimulated by ascorbate (ASC) and its natural precursor I-galactone-gamma-lactone (GL). When incubation media were supplemented with lycorine (Lyc), an inhibitor of the ASC biosynthesis, root growth was negligible even in the presence of ASC or GL. ASC completely inhibited in vitro guaiacol peroxidase activities that were isolated from both the apoplast and the cell wall. However, ferulic-acid-dependent peroxidase from the cell wall was partially inhibited by ASC, whereas ferulic acid peroxidase activity from the apoplastic fluid was completely inhibited by ASC as long as ASC was present in the assay medium. ASC content in cells was increased by preincubations with ASC or GL, whereas Lyc reduced it. On the other hand, ASC or GL treatments decreased both apoplast and cell-wall-bound peroxidase activities, whereas Lyc had a slight stimulating effect. These results are discussed on the basis of a possible control of root elongation by ASC via its action on peroxidases that are involved in the regulation of cell-wall extensibility
ISSN:0032-0889
1532-2548
DOI:10.1104/pp.112.3.1119