Mediates an active uptake of hexoses, probably by sugar/hydrogen symport. Can transport glucose, galactose, mannose, xylose and 3-O-methylglucose, but not fructose and ribose. Inhibited by uncouplers such as 2,4-dinitrophenol and carbonyl cyanide-m-chlorophenyl-hydrazone. Optimum pH is 5.5. Specifically expressed in germinating pollen and pollen tube (at protein level). Belongs to the major facilitator superfamily. Sugar transporter (TC 2.A.1.1) family.