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Effects of leaf age, basal meristem and infection with powdery mildew on photosynthesis in barley grown in 700 μmol mol −1 CO 2
Author(s) -
HIBBERD J. M.,
RICHARDSON P.,
WHITBREAD R.,
FARRAR J. F.
Publication year - 1996
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.1996.tb04636.x
Subject(s) - photosynthesis , powdery mildew , carboxylation , rubisco , biology , botany , mole , ribulose , acclimatization , plant physiology , horticulture , biochemistry , catalysis
summary The rate of net photosynthesis in the second leaf of barley was higher in 700 than 350 μmol mol −1 CO 2 , when measured in the CO 2 concentration in which the plants were grown, but the magnitude of this difference decreased as the leaf aged. Infection by powdery mildew accelerated the decline in net photosynthesis of leaves grown in either 350 or 700 μmol mol −1 CO 2 . A/C i curves allowed the reduction in net photosynthesis of plants exposed to 700 μmol mol −1 CO 2 or after infection by powdery mildew to be related to changes in the carboxylation efficiency or in the regeneration of ribulose 1,5‐bisphosphate. The carboxylation efficiency declined in plants exposed to 700 μmol mol −1 CO 2 . In plants infected with powdery mildew, the reduction in net photosynthesis was associated with both reduced carboxylation efficiency and reduced ability to regenerate ribulose 1,5‐bisphosphate. Reduced carboxylation efficiency of the second leaf of plants grown in 700 μmol mol −1 CO 2 , was not associated with a reduction in the concentration of rubisco within the leaf. In contrast to the presence of a close exogenous sink, leaf age had large effects on the acclimation of photosynthesis to 700 μmol mol −1 CO 2 .