Morphology And Ultrastructure Of The Reproductive System Of The Phytophagous Leafhopper Psammotettix Striatus (L.)

The phytophagous leafhopper Psammotettix striatus (L.) (Hemiptera: Cicadellidae), widely distributes in the northern hemisphere. While its feeding does little directly damage, P. striatus, a primary vector of the highly destructive wheat blue dwarf (WBD) phytoplasma, is a serious pest of wheat crops in northwest China and north China area. A microscopic analysis of mophology and ultrastructure of the reproductive system of P. striatus were studied by light microscopy (LM) and transmission electron microscopy (TEM). Ultrastructure of sperm and egg of P. striatus by TEM also was conducted. The major conclusions are as follow:The gross morphology of the reproductive system showed that the male reproductive system of P. striatus consists of paired testes with six testicular follicles each, a pair of vas deferens, a pair of seminal vesicles, a pair of lateral ejaculatory ducts, a single common ejaculatory duct and a couple of accessory glands. Tenuous vas deferens connect a pair of seminal vesicle; seminal vesicle links to vas deferens, lateral ejaculation duct and accessory gland; there is a crispation in the middle of bulky accessory gland; the end of annular lateral ejaculation duct mergers to common ejaculation tube; the lateral ejaculation duct is strongly elongated, whereas the common ejaculation tube is short. The famale reproductive system of P. striatus consists of paired ovary, two lateral oviducts, spermatheca, a bursa copulatrix and single one accessory gland. Each symmetric ovary consists of six ovarian tubes, whose end is six ligament focused on one point which is attached to the back of the body wall. Each ovarian tube is connected to the calyx. Common oviduct lies in the junction of spermatheca and vagina. Long egg-shaped bursa copulatrix opens into the vagina, accessory gland and spermatheca; tubular accessory gland lies in bursa copulatrix.Our studies also show that the reproductive system of P. striatus is histologically very simple. It is composed of more-or-less flattened epithelium of a secretory type, and muscle fibres. Testicular follicles and ovarian tubule contain plasma membranes and relatively thin muscle layer. However, muscle layer is relatively thick in the vas deferens, seminal vesicle, male accessory gland, common ejaculatory duct and bursa copulatrix. The vas deferens has undeveloped epithelial cells and abundant microvilli. Testicular follicles are rich in abundant microvilli and electron-dense granule. The epithelium of the developed male accessory glands are filled with web-like secretions, rough endoplasmic reticulum and fat body. In seminal vesicle, many electron-dense granules as well as secretions are discovered. At the terminal regions of ovarioles, many folliclar cubic cells are observed. The epithelium of the calyx contains abundant rough endoplasmic reticulum, fat bady and a mass of protein grain. More electron-dense granules as well as secretions are observed in the cytoplasm of the bursa copulatrix. Many infoldings are also observed in the common ejaculatory duct.The features of the spermatozoa of the P. striatus examined include a bilayered acrosome with a central perforatorium, an elongated homogeneously condensed nucleus, centriole adjunct and a flagellum with a 9+9+2 axoneme pattern, two accessory bodies and two mitochondrial derivatives. The head of the sperm consists of an anteriorly positioned conical acrosome that has tubular substructure and a deep, posterior invagination that forms the subacrosomal space. The acrosome is flattened anteriorly; posteriorly it extends along either side of the nucleus as two tubular processes that gradually decrease in diameter and different level of grooves are formed. The electron dense materials are covered on the acrosomal from across-sections. The centriole adjunct initiates to the nucleus and terminates in the region anterior to the mitochondrial derivatives. The axoneme contains nine accessory bubules,nine doublet microtubules and two central microtubules.Follicles cells locate at the distal regions of the egg. At the fist stage do not exhibits intercellular space between eggs shell and yolk membrane. After the further secretory activity of follicular cells, the spaces are larger than those observed in the previous stage and filled with air, in order to satisfy eggs breathing.