Further studies on the flagellar apparatus in Oomycetes; Anterior roots

Zoospores of six species of Phytophthora, two species of Pythium, Saprolegnia diclina and Peronophythora litchii were examined to resolve the orientation, extent, and possible connection of the anterior roots of the flagellar apparatus. The anterior ribbed root (R1) extends from the right side of the kinetosome to the anterior end of the cell where it arches to the left, and extends back towards the center of the cell. The anterior doublet root (R2) extends from the left side of the kinetosome and runs under the cell membrane on either the left or right side of the flagellar groove. The two roots are separate. From some angles they appear to overlap, but they do not connect. The zoospore of P. litchii, not previously studied in the transmission electron microscope, is cytologically similar to other zoospores in the Pythiaceae and Peronosporaceae.