Naslov
X-ray diffraction study of calcification processes in embryos and larvae of the brooding oyster Ostrea edulis

Autori
Medaković, Davorin ; Popović, Stanko ; Gržeta, Biserka ; Plazonić, Miljenka ; Hrs-Brenko, Mirjana

Izvornik
Marine biology (0025-3162) 129 (1997), 4; 615-623

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
X-ray diffraction; calcification; biomineralization curve; embryos; larvae; oyster; Ostrea edulis

Sažetak
X-ray powder diffraction was used to study shell calcifications of the oyster Ostrea edulis, sampled in the Limski Kanal, Istria (Adriatic Sea), in May 1992. All the developmental stages were followed, from the embryonic stage through transition between the trochophore and veliger larva (prodissoconch I and II) and later, after swarming, the pelagic free-swimming larval stages, up to their settlement and attachment (from the D-shaped to the fully pediveliger larva), and finally during metamorphosis and juvenile stages (dissoconch). In the first gastrula stage, only an amorphous tissue is present (a periostracum and organic matrix). The beginning of shell formation (at the end of gastrulation)in early trochophores is manifested by the appearance of calcite (up to 1-7% of total volume) and then aragonite (about 1%). In the later stage of the veliger larva the fraction of calcite decreases as well as amorphous fraction, while the fraction of aragonite rapidly increases. In the prodissoconch II stage and during the whole pelagic period aragonite is dominant, accompanied by a very small amorphous fraction and traces of calcite. The shell mineral composition does not change until metamorphosis, whereupon the fraction of calcite rapidly increases andthe fraction of aragonite decreases. The postmetamorphic valves of the juvenile and adult oyster consist mainly of calcite, except the resilium and myostracum which remain aragonitic, possibly as a continuation of the inner layer of the larval shell.

Izvorni jezik
Engleski

Znanstvena područja
Kemija, Biologija

POVEZANOST RADA