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Title: Sugar transport by maize endosperm suspension cultures. [Zea mays]

Conference · · Plant Physiol., Suppl.; (United States)
OSTI ID:6071294

To determine the mechanism of sugar uptake by suspension cultures derived from developing maize (Zea mays L.) endosperm, incorporation of radioactivity from /sup 14/C-sugars by the tissue in the mid-log phase of growth was examined. Among the sugars tested was l'-deoxy-l'-fluorosucrose (FS), a derivative not hydrolyzed by invertase but recognized by sucrose carriers in other systems. At 40 mM, uptake of label from FS was 23% of that from sucrose, while uptake of label from L-glucose (used as a control for medium carry-over and adsorption) was 16% of that from sucrose. Uptake of label from sucrose did not increase at concentrations above 50 mM, possibly due to a rate-limiting requirement for extracellular hydrolysis. Kinetic analysis revealed both saturable and linear components of uptake for glucose and fructose. The rate of fructose uptake exceeded that of glucose at all concentrations. Fructose uptake at 20 mM was inhibited by NaN/sub 3/, HgCl/sub 2/, dinitrophenol, carbonyl cyanide m-chlorophenylhydrazone, and p-chloromercuribenzenesulfonic acid. Results suggest that sucrose is hydrolyzed prior to uptake, and that fructose is transported preferentially by a carrier sensitive to an external sulfhydryl group inhibitor. Metabolic activity is required for sugar uptake. The specificity of the hexose transporter is currently being investigated.

Research Organization:
Dept. of Agriculture, Peoria, IL
OSTI ID:
6071294
Report Number(s):
CONF-8707108-; TRN: 87-037436
Journal Information:
Plant Physiol., Suppl.; (United States), Vol. 83:4; Conference: Annual meeting of the American Society of Plant Physiologists, St. Louis, MO, USA, 19 Jul 1987
Country of Publication:
United States
Language:
English