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Effects of light on respiration and oxygen isotope fractionation in soybean cotyledons
Author(s) -
RibasCarbo M.,
Robinson S. A.,
GonzàlezMeler M. A.,
Len A. M.,
Giles L.,
Siedow J. N.,
Berry J. A.
Publication year - 2000
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1046/j.1365-3040.2000.00607.x
Subject(s) - fractionation , alternative oxidase , darkness , respiration , glycine , chemistry , oxygen , sugar , oxidase test , cellular respiration , botany , isotopes of oxygen , biochemistry , biophysics , biology , enzyme , chromatography , nuclear chemistry , amino acid , organic chemistry
Light effects on electron flow through the cyanide‐resistant respiratory pathway, oxygen isotope fractionation and total respiration were studied in soybean ( Glycine max L.) cotyledons. During the first 12 h of illumination there was an increase in both electron partitioning through the alternative pathway and oxygen isotope fractionation by the alternative oxidase. The latter probably indicates a change in the properties of the alternative oxidase. There was no engagement of the alternative oxidase in darkness and its fractionation was 27‰. In green cotyledons 60% of the respiration flux was through the alternative pathway and the alternative oxidase fractionation was 32‰. Exposing previously illuminated tissue to continuous darkness induced a decrease in the electron partitioning through the alternative pathway. However, this decrease was not directly linked with the low cellular sugar concentration resulting from the lack of light because 5 min of light every 12 h was sufficient to keep the alternative pathway engaged to the same extent as plants grown under control conditions.