Feeding of Tylenchorhynchus Dubius

The feeding of Tylenchorhynchus dubius on epidermal cells and root hairs of seedling roots of Brassica rapa var. silvestris was studied and analysed with the aid of cine film. The cell wall was punctured by rapid and characteristically irregular stylet thrusts. During salivation salivary granules flowed continuously from the site of synthesis in front of the dorsal gland-cell nucleus, through the gland duct towards the gland reservoir. Inside the cell a clear zone developed around the stylet tip and cytoplasm then accumulated there. The median bulb muscles contracted spasmodically, but uncoordinatedly so that the metacorporeal lumen was not dilated. At the onset of ingestion the forward flow of salivary granules through the duct was stopped by pump pulsations which soon became steady and very fast. Cytoplasm continued to accumulate around the clear zone in the food cell. Granular constituents of the cytoplasm were never seen to be drawn into the stylet. The accumulated cytoplasmic mass was never completely removed. After the nematode's departure this mass started to coagulate first. Cyclosis slowed down and finally stopped. Parasitized root hairs stopped growing. A comparison is made between the feeding of T. dubius and Trichodorus similis on the same host species.