Mediates an active uptake of hexoses, probably by sugar/hydrogen symport. Can transport glucose, 3-O-methylglucose, mannose, fructose and galactose, and, to a lower extent, xylose and ribulose. Inhibited by uncouplers such as 2,4-dinitrophenol and carbonyl cyanide-m-chlorophenyl-hydrazone. Pollen specific. First observed in pollen right before the opening of floral buds. Levels increase during pollen maturation. Belongs to the major facilitator superfamily. Sugar transporter (TC 2.A.1.1) family.