Staining of invertase activity on the parts of the transverse sections of a maize root tip from the region of the beginning of the elongation zone (A, B) and from the basal part of the meristem (C). The parts of the sections contain rhizodermis (rh), cortex (cor), endodermis (en), pericycle (pc) and stele (A, B) and a region of vascular cylinder (C). The reaction with (A, C) or without (В) sucrose in the incubation medium. Bar – 100 µm (A, B), 25 µm (C). ph – phloem, mx – metaxylem vessel, px – protoxylem vessel.