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Ultrastructural and cytochemical aspects of oogenesis in Castrada viridis (platyhelminthes, rhabdocoela)
Author(s) -
Falleni Alessandra,
Lucchesi Paolo
Publication year - 1992
Publication title -
journal of morphology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 74
eISSN - 1097-4687
pISSN - 0362-2525
DOI - 10.1002/jmor.1052130208
Subject(s) - biology , ultrastructure , endoplasmic reticulum , eggshell , golgi apparatus , turbellaria , anatomy , microbiology and biotechnology , oocyte , cytochemistry , embryo , ecology
The heterocellular female gonad of the typhloplanoid Castrada viridis consists of a single germarium and two rows of vitellaria. The germarium, composed of a germinative zone and a growth zone, is surrounded externally by a layer of accessory cells the function of which is hypothesized in this study. The main feature of oocyte differentiation is the synthesis of small electron‐dense inclusions produced by the rough endoplasmic reticulum (R.E.R.) and Golgi complex. The electron‐dense content of the egg inclusions reacts positively to the cytochemical test used to detect polyphenols and is only partially extracted following incubation in protease. The genesis, composition, and peripheral location of egg inclusions in mature oocytes suggest that they could represent residual eggshell granules. The presumed function of eggshell granules is discussed and their fine morphology is compared with that observed in other neoophoran Platyhelminthes. © 1992 Wiley‐Liss, Inc.