Summary—Polyclonal antibodies directed against α,l‐1.2‐arabinofuranosyl poly‐β,d‐1.4‐xylopyranosyl (degree of polymerization 130) have been raised from rabbits. The immunogold labelling in transmission electron microscopy (TEM) evidenced the arabinoxylans of the plant cell walls. Comparison between the stems of normal and mutant bm3 maize demonstrated a greater accessibility of arabinoxylans in the walls of the mutant maize. The method, specific and swift, allows us to specify the repartition in the different parts of the stem: sclerenchyma, fiber