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Posidonija (Posidonia oceanica (L.) Delile) je morska cvjetnica i endem Sredozemnog mora. Izrazito je osjetljiva vrsta pa je stoga pogodan bioindikator stanja u morskom okolišu. Cilj istraţivanja bio je utvrditi količine fotosintetskih pigmenata (klorofila a i b te ukupnih karotenoida) u intermedijarnim listovima posidonije prikupljenim na dubinama od 2 (3) i 10 m na tri različita lokaliteta zadarskog akvatorija (Zadarski kanal, Zaglav i Brbišćica) u četiri godišnja doba. Rezultati istraţivanja pokazali su da udjeli fotosintetskih pigmenata imaju sličan sezonski trend promjena vrijednosti na pojedinoj dubini i lokalitetu. Određeno odstupanje uočeno je u količini ukupnih karotenoida u biljkama iz Zadarskog kanala i dubine od 2 m. U Zaglavu je na 10 m dubine količina pigmenata tijekom godine bila relativno konstantna zbog zasjenjenosti staništa. Omjer klorofila a i b je većinom bio viši na dubini od 10 m, dok se omjer klorofila i karotenoida na obje dubine pokazao konstantnim samo za Brbišćicu. Tekućinskom kromatografijom visoke djelotvornosti iz ekstrakta listova posidonije razdvojeni su klorofil a i b, neoksantin, violaksantin, lutein, β-karoten, i α-karoten. S obzirom na ovisnost količine fotosintetskih pigmenata o okolišnim uvjetima mogu zaključiti da bi oni mogli biti dobri pokazatelji promjena u okolišu. Marine phanerogam Posidonia oceanica (L.) Delile is an endemic species of the Mediterranean Sea. It is extremly sensitive and therefore suitable bioindicator of changes in the marine environment. The aim of this study was to determine the photosynthetic pigments content (chlorophyll a and b and total carotenoids) in the intermediate leaves of P. oceanica collected at depths of 2 (3) and 10 m at three different sites of the coastal area of Zadar (Zadarski kanal, Zaglav and Brbišćica Bay) during the four seasons. The content of photosynthetic pigments have a similar trend of seasonal changes at a particular depth and site. Certain deviation was observed in the amount of total carotenoids in plants from Zadarski kanal at depth of 2 m. In Zaglav Bay at 10 m depth the amount of pigments was relatively constant during the four seasons due to shaded habitat. The ratio of chlorophyll a and b was mostly higher at a depth of 10 m, while the ratio of total chlorophylls and carotenoids on both depths was constant for Brbišćica Bay. High performance liquid chromatography of P. oceanica leaves extracts separated chlorophyll a and b, neoxanthin, violaxanthin, lutein, β- carotene, and α-carotene. Observed dependence of the quantity of photosynthetic pigments on environmental conditions leads to conclusion that they could be good indicators of environmental changes. |
