Toluidine blue-stained seed sections
(Fig. 3A and B) showed the PE envelope enclosing the cotyledons.
In sections of pistil-inoculated seeds, A. citrulli cells were
observed not only in the inner cells of the PE envelope, but also in
the intercellular spaces of parenchyma tissue of the embryo (Fig.
3C). In pericarp-inoculated seeds, A. citrulli was observed only in
the outer layer of PE envelope (Fig. 3D). A. citrulli cells were not
observed in the embryo of pericarp-inoculated seeds.