Colonization of cantaloupe roots by Monosporascus cannonballus.

Penetration of Monosporascus cannonballus into and growth within cantaloupe roots was studied using light and electron microcopy. Germ tubes penetrated the epidermis, and hyphae grew, without branching, almost directly to the xylem. The hyphae traversed the endodermis into protoxylem cells, and then grew extensively within the lumen of metaxylem vessels.