Ultrastructure of embryonic envelopes and integument of Oncopeltus fasciatus dallas (Insecta, Heteroptera)

摘要: The embryo ofOncopeltus fasciatus forms a typical secondary dorsal organ (SDO). It develops after katatrepsis from the contracting serosa, cells of which decrease in diameter but increase considerably height. After 66 h, SDO represents protrusion serosal epithelium above head and is then reduced to disc-shaped formation, sinks into yolk, where it disintegrates 80 h. During its expression, between 78 shows zonal arrangement cell organelles. nucleus, located basal region, has very irregular outline includes several nucleoli globular inclusion bodies. Rough smooth ER are well developed around nucleus suggest involvement protein secretion as lipid metabolism. Electron-lucent vacuoles electron-dense granules, sometimes enclosed vacuoles, accumulate apical obviously extruded peripheral (extraembryonic) space. formation intercellular clefts delicate cytoplasmic extensions facing yolk microvilli periphery evidence transporting function epithelium. Blisters intercalated extended junctional complexes regions point transport solutes. Because similarities processes observed Malpighian tubules larvae, an excretory suggested. Final products apparently transported extraembryonic space, they during embryogenesis. Phylogeny, relationship, different embryonic glands Arthropoda (primary DO pleuropodia) discussed.