Electron microscopical studies on Ditylenchus dipsaci (Kühn). I. Stomatal region.

Abstract

The stomatal region of Ditylenchus dipsaci, approximately 15 μ long, was studied in cross-section. The cuticle consists of a thin cortex and a thick matrix whose inner layer consists of regularly arranged crystalloid structures. The head skeleton is basically a hexagonal tube with six radiating blades. The somatic musculature begins with two muscle cells in each sector. Each muscle cell consists of alternating bands of thick and thin myofilaments. Three stylet protractors are present which gradually become trifid as they extend anteriorly. They originate at the body wall and are inserted on the ridges on the surfaces of the stylet knobs. The guiding apparatus consists of a steep-sided cone and a cylindrical stalk of approximately the same length. Its anterior end is fused onto the base of the head skeleton and its posterior end fuses onto the anterior surface of the stylet knobs. The four dorsolateral and ventrolateral cephalic nerves could be traced from the level of the stylet knobs. Each of them branches twice. The two lateral cephalic nerves do not seem to conform to the same branching pattern. Cilia were observed in the amphidial pouches. The two myelin figures observed were identified as part of the amphidial nerves but there is no conclusive evidence that the cilia are their end processes.