title: Control of ascorbic acid synthesis and accumulation and glutathione by the incident light red/far red ratio in Phaseolus vulgaris leaves.
abstract: The effects of red/far red (R/FR) ratios on leaf ascorbate (AA) and glutathione (GSH) accumulation were examined in common bean (Phaseolus vulgaris L.). Growth under low R/FR ratios resulted in a "shade" phenotype and much lower leaf AA and GSH contents than high (R/FR) ratios. Photosynthesis rates were unaffected by changes in the R/FR ratio but leaf respiration rates, pyridine nucleotide pools and antioxidant enzyme activities were decreased under the low R/FR regime. The GSH pool changed slowly in response to altered R/FR ratios but leaf ascorbate acclimated over a single photoperiod. We conclude that light quality signals, particularly R/FR ratios, are important regulators of antioxidant synthesis and accumulation. These acclimatory changes are an early response to changing light environment.
authors.affiliation: Instituto de Fisiología Vegetal, Facultad Ciencias Agrarias y Forestales, Universidad Nacional de La Plata, CCT-CONICET, La Plata, Argentina. carlos.bartoli@agro.unlp.edu.ar
authors.forename: Carlos G
authors.initials: CG
authors.lastname: Bartoli
authors.forename: Eduardo A
authors.initials: EA
authors.lastname: Tambussi
authors.forename: Fanello
authors.initials: F
authors.lastname: Diego
authors.forename: Christine H
authors.initials: CH
authors.lastname: Foyer
mesh_terms: D001205:Ascorbic Acid / Q000096:biosynthesis*; D005978:Glutathione / Q000378:metabolism*; D008027:Light; D027805:Phaseolus / Q000378:metabolism* / Q000528:radiation effects; D010788:Photosynthesis; D018515:Plant Leaves / Q000378:metabolism* / Q000528:radiation effects
chemical_list: D005978:Glutathione; D001205:Ascorbic Acid