Ultrastructure of the salivary glands of the planthopper, peregrinus maidis (ashmead) (Homoptera : Delphacidae)

Abstract

The principal salivary gland of the planthopper, Peregrinus maidis (Ashmead) (Homoptera : Delphacidae), comprises 8 acini of only 6 ultrastructurally different acinar types. In these acini, secretory cells contain elongated vacuoles partly lined by microvilli and by microtubule bundles. These vacuoles are apparently connected with extracellular canaliculi deeply invaginated into secretory cells. Canaliculi of each acinus lead to a ductule lumen, which is lined with spiral cuticular intima, surrounded by duct cells. Striated muscle fibers, supplied with small nerve axons and tracheoles, are found in various acini of the principal gland, usually around secretory and duct cells. In the accessory salivary gland, the 2 large secretory cells contain no elongated vacuoles or canaliculi invaginations. However, in their central region, apically, these cells border a large microvilli-lined canal with its own canal cells. This canal is apparently connected with the cuticle-lined accessory duct, formed by duct cells. Nerve axons, but no muscle fibers, are found in the accessory gland and its duct. It is suggested that the system for transporting secretory material within acini of the principal gland, is basically different from that within the accessory gland.