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THE EFFECT OF ORTHOPHOSPHATE CONCENTRATION AND EXOGENOUSLY SUPPLIED SUGARS ON THE DISTRIBUTION OF NEWLY FIXED CARBON IN SUGAR BEET LEAF DISCS
Author(s) -
HEROLD A.,
McGEE E. E. M.,
LEWIS D. H.
Publication year - 1980
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.1469-8137.1980.tb04442.x
Subject(s) - maltose , sucrose , sugar beet , starch , sugar , sugar phosphates , incubation , mannose , chemistry , chloroplast , carbon fibers , biochemistry , chenopodiaceae , botany , phosphate , biology , horticulture , materials science , composite number , gene , composite material
SUMMARY The apportioning of newly fixed carbon in leaf discs of sugar beet ( Beta vulgaris L.) is dependent on the incubation medium. Concentration of orthophosphate (Pi) influences the distribution of carbon between chloroplast starch and the cytoplasm, and the proportion of 14 C incorporated into sucrose. In the presence of exogenous sucrose and glucose, starch synthesis is enhanced and gross changes in cytoplasmic metabolite pools occur. These observations are discussed in relation to sink/source interactions of whole plants. In the presence of mannose, which sequesters cytoplasmic Pi in leaves of sugar beet as mannose‐6‐phosphate, sucrose synthesis is severely inhibited and maltose accounts for up to 30 % of the fixed carbon. This is related to earlier reports of unusual accumulation of maltose.