Fiziološke prilagodbe jadranskog bračića (Fucus virsoides J. Agardh) na isušivanje i ultraljubičasto zračenje

master's thesis

• Title (english): Physiological adaptations of Fucus virsoides J. Agardh on desiccation and ultraviolet radiation
• Author: Nikola Hanžek
• Mentor: Mirta Tkalec (mentor)
• Committee member: Mirta Tkalec (predsjednik povjerenstva)
• Committee member: Biljana Balen (član povjerenstva)
• Committee member: Jasna Lajtner (član povjerenstva)
• Committee member: Zrinka Ljubešić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2014-02-21, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology

Abstract

Jadranski bračić (Fucus virsoides J. Agardh) je endemična smeđa alga Jadranskog mora koja raste u zoni plime i oseke pa se zbog stalnih promjena u okolišu morala prilagoditi na ekstremne životne uvjete. Cilj istraživanja bio je odrediti koncentraciju fotosintetskih pigmenata, fenolnih spojeva i lipidnih peroksida u algama izloženim ultraljubičastom (UV) zračenju, isušivanju i njihovoj kombinaciji te utvrditi postoji li razlika u fiziološkim prilagodbama i odgovoru na izlaganje istraživanim stresnim čimbenicima. Koncentracije fotosintetskih pigmenata klorofila a, karotenoida i fukoksantina bile su više ujutro i navečer kada su intenziteti i UV zračenja i vidljive svjetlosti bili niži, dok je tijekom podneva došlo do pada koncentracije pigmenata. S obzirom da nije došlo do povećanja koncentracije lipidnih peroksida koji bi ukazivali na oksidacijska oštećenja, može se zaključiti da promjene u koncentraciji pigmenata nisu samo posljedica, nego sudjeluju u prilagodbi jadranskog bračića na visoke intenzitete svjetlosti. UV zračenje nije potaknulo akumulaciju florotanina i flavonoida što upućuje da ove dvije grupe spojeva ne sudjeluju značajno u zaštiti od zračenja. Porast koncentracije lipidnih peroksida u algama tijekom isušivanja pokazuje da jadranski bračić nije u potpunosti prilagođen isušivanju. Koncentracija fukoksantina i karotenoida se također povećala s duljinom isušivanja iz čega se može pretpostaviti da imaju zaštitnu ulogu.

Abstract (english)

Brown seaweed Fucus virsoides (J. Agardh) is an endemic alga of the Adriatic Sea, that inhabits the tidal zone. Due to constant changes in its environment, Fucus virsoides had to adapt to the extreme conditions. Aim of this research was to determine concentrations of photosynthetic pigments, phenolic compounds and lipid peroxides in algae that were exposed to ultraviolet (UV) light, desiccation, or both, and to find out if there was a difference in physiological adaptations to different stressors. Concentrations of photosynthetic pigments (chlorophyll a, carotenoids and fucoxanthin) were the highest in the morning and evening, when the intensities of the UV and visible light were lower, while the concentrations were lower during the midday. Since there was no increase in the concentration of lipid peroxides, which would indicate oxidative damage, it can be concluded that changes in pigments concentrations are not just a consequence, but can contribute to adaptation of Fucus virsoides to high light intensity. UV light did not induce accumulation of phlorotannins and flavonoids, which suggests that these two groups of compounds do not protect seaweed from UV significantly. Higher concentration of lipid peroxides, indicating oxidative stress, occurred after longer exposure of algae to dryness, which shows that Fucus virsoides is less adapted to desiccation. Concentrations of carotenoides and fucoxanthin also increased during desiccation stress, which suggests that they could have a protective role.

• Keywords: jadranski bračić; UV zračenje; isušivanje; fotosintetski pigmenti; fenolni spojevi; oksidacijski stres
• Keywords (english): Fucus virsoides; UV light; desiccation; photosynthetic pigments; phenolic compounds; oxidative stress
• Language: croatian
• URN:NBN: urn:nbn:hr:217:598992
• Study programme: Title: Ecology; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra ekologije i zaštite prirode (magistar/magistra ekologije i zaštite prirode)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2017-04-26 09:12:35