Učinak dušika na fotosintetsku učinkovitost i pigmente u lišaja Evernia prunastri

master's thesis

• Title (english): The effect of nitrogen on photosynthetic efficiency and pigments in the lichen Evernia prunastri
• Author: Božana Ćavarušić
• Mentor: Mirta Tkalec (mentor)
• Committee member: Mirta Tkalec (predsjednik povjerenstva)
• Committee member: Ines Radanović (član povjerenstva)
• Committee member: Iva Juranović Cindrić (član povjerenstva)
• Committee member: Draginja Mrvoš-Sermek (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2017-09-21, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology

Abstract

Lišajevi su fotosintetski organizmi koji se često koriste kao bioindikatori zagađenja zraka. Vrsta lišaja Evernia prunastri vrlo je osjetljiva na zagađenje zraka dušikovim spojevima. Štetan utjecaj dušikovih spojeva povezan je i s drugim okolišnim parametrima poput osvjetljenja i vlažnosti. Cilj ovog istraživanja bio je provjeriti kako dušik u obliku amonijevih iona odnosno nitrata djeluje na fotosintetsku učinkovitost i pigmente lišaja Evernia prunastri. Uzorci lišajeva tretirani su 30 minutnim uranjanjem u 1 M otopinu kalijevog nitrata, 1 M otopinu amonijevog nitratai 0,5 M otopinu amonijevog sulfata. Dio uzoraka tijekom trajanja pokusa izložen je slabijem intenzitetu svjetla (40 μmol fotona m-2 s-1), a dio jačem (100 μmol fotona m-2 s-1) kako bi se utvrdio utjecaj osvjetljenja. Mjerenje fluorescencije klorofila a i određivanje udjela klorofila a, klorofila b, ukupnih karotenoida te kvocijenta feofitinizacije napravljeno je 3., 7. i 14. dan nakon tretmana dušikom. Rezultati su pokazali da dušikovi spojevi imaju značajan negativan učinak na fotosintezu u lišaja Evernia prunastri budući da su uzrokovali sniženje vrijednosti parametara fluorescencije klorofila kao i smanjenje udjela fotosintetskih pigmenata u tkivu. Značajniji utjecaj pokazali su tretmani dušikom u obliku amonijevih iona, a nešto manji utjecaj oni gdje je dušik bio samo u obliku nitrata. Izlaganje lišajeva tretiranih dušikom jačem intenzitetu svjetlosti imalo je negativniji utjecaj na fotosintetsku učinkovitost i pigmente u odnosu na izlaganje slabijem intenzitetu.

Abstract (english)

Lichens are photosynthetic organisms that are often used as bioindicators of air pollution. One of the lichen species that is very sensitive to air pollution by nitrogen compounds is Evernia prunastri. The harmful effect of nitrogen compounds is related also to the other environmental parameters such as light intensity and humidity. The goal of this research was to find out how nitrogen in the form of ammonium ions or nitrates affects photosynthetic efficiency and pigments of the Evernia prunastri. Lichen samples were treated by immersion in a 1 M potassium nitrate solution, a 1 M ammonium nitrate solution and a 0,5 M ammonium sulfate solution for 30 minutes. In order to determine the influence of light, one group of the samples was exposed to a lower light intensity (40 μmol photon m-2 s-1) and another to a higer light intensity (100 μmol photon m-2 s-1) during the experiment. Chlorophyll a flourescence measurements as well as the determination of the content of chlorophyll a, chlorophyll b and carotenoids, and the phaeophytinization quotient were done on the 3rd, 7th and 14th day after the nitrogen treatment. The results showed that nitrogen compounds have a significant negative effect on photosynthesis of the Evernia prunastri since they caused a decrease of chlorophyll flourescence parameters as well as a decrease in the content of photosynthetic pigments in lichen tissue. A treatment with nitrogen in the form of ammonium ions had a more severe effect than a treatment with nitrogen applied only in the form of nitrate. Exposure of nitrogen-treated lichen to a higher light intensity had a more negative effect on the photosynthetic performance and pigments than exposure to a lower light intensity.

• Keywords: fotosinteza; pigmenti; kalijev nitrat; amonijev nitrat; amonijev sulfat; svjetlost
• Keywords (english): photosyntesis; pigments; potassium nitrate; ammonium nitrate; ammonium sulfate; light
• Language: croatian
• URN:NBN: urn:nbn:hr:217:189243
• Study programme: Title: Integrated undergraduate and graduate university study of Biology and Chemistry Education; specializations in: Integrated undergraduate and graduate university study of Biology and Chemistry Education; Course: Integrated undergraduate and graduate university study of Biology and Chemistry Education; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: magistar/magistra edukacije biologije i kemije (magistar/magistra edukacije biologije i kemije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access; Embargo expiration date: 2018-09-21
• Created on: 2017-10-20 11:10:44