Fig. 2.

Autofluorescence emitted by cross sections of sorghum roots. (A) Blue, (B) green, and (C) merged image of both signals in Si+ roots. Arrows indicate silica aggregates. The blue fluorescence is more intense at the base and edges of a silica aggregate than in the cell wall itself and at the tip of the aggregate. Green fluorescence of the ITCW outlines the aggregate. (D) Blue, (E) green, and (F) merged image of both signals in Si– roots. Arrows mark the location of spots of green fluorescence in the ITCW. c, cortex; e, endodermis; p, pericycle. Scale bars=10 µm.