Pokazatelji toksičnosti teških metala u vodenoj leći (Lemna minor L.) i luku (Allium cepa L.)

master's thesis

• Title (english): Indicators of heavy metal toxicity in duckweed (Lemna minor L.) and onion (Allium cepa L.)
• Author: Valerija Vujčić
• Mentor: Branka Pevalek-Kozlina (mentor)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2008, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology

Abstract

Vodena leća se često koristi kao modelna biljka zbog svoje osjetljivosti na različite toksične tvari te jednostavnog i brzog uzgoja. Običan luk je vrlo pogodan za istraživanje genotoksičnosti zbog malog broja vrlo dugačkih kromosoma (2n = 16). Teški metali prvotno djeluju na korijenski sustav te se dalje mobiliziraju uslijed transpiracije uzrokujući klorozu listova i inhibiciju rasta. Istraživala sam fitotoksične i genotoksične učinke teških metala nasađivanjem vodene leće i običnog luka na površinske vode (Sava Županja, Sava Jesenice i Sutla Prišlin) uzorkovane tijekom 3 mjeseca te otpadne vode ZGOS (uzorkovane kroz 24 sata) i Jakuševac. Biljni materijal je uziman nakon tjedan dana (vodena leća) ili 24h (luk) inkubacije. Metodom atomske apsorpcijske spektrometrije u uzorkovanim vodama su određeni esencijalni i neesencijalni teški metali. U ovom radu praćeni su rast i relativna masa svježe tvari, sadržaj klorofila i karotenoida, aktivnost gvajakol peroksidaze te citogenetička analiza. Svi uzorci voda su izazvali inhibiciju relativnog prirasta broja biljaka i relativne mase svježe tvari, smanjenje sadržaja klorofila i karotenoida te aktivnosti gvajakol peroksidaze. Aktivnost tog antioksidacijskog enzima bila je povećana samo u uzorcima otpadne vode ZGOS 4 i 5. Smjesa teških metala uzrokovala je inhibiciju rasta korjenčića i morfološke promjene kao što su vrškovi zavinuti u obliku kuke. Teški metali iz testnih voda smanjili su mitotski indeks i broj stanica u pojedinim fazama staničnog ciklusa. Citogenetička analiza pokazala je najveći broj kromosomskih aberacija u otpadnim vodama te površinskoj vodi Sutla Prišlin. Najčešće kromosomske aberacije prisutne u uzorcima, sljepljivanje, c-mitoza i zaostali kromosomi su vjerojatno posljedica povećanih količina olova, kroma i žive u uzorcima vode. Rezultati dobiveni u ovom radu na dvjema biljnim vrstama, vodenoj leći i luku, ukazuju na fito-, cito- i genotoksične tvari u uzorkovanim vodama i indiciraju potencijalan rizik ne samo za biljne vrste nego i za sve žive organizme.

Abstract (english)

Duckweed (Lemna minor L.) is often used as a plant model because it is a widely spread monocot, multiplies rapidly and shows tremendous metal accumulating capacity. Onion (Allium cepa L.) is suitable candidate for genotoxicity studies because it has a small number of large chromosoms (2n = 16). Heavy metals enter the plant tissues through the root system and then mobilize to leaves causing chlorosis and growth inhibition. I investigated phytotoxic and genotoxic effects of heavy metals present in chosen surface (Sava Županja, Sava Jesenice i Sutla Prišlin taken every month during 3 months) and waste waters (ZGOS taken every 4 hours during 24 hours and Jakuševac) using duckweed and onion as plant test systems. Plant material was harvested after seven days (duckweed) or 24 hours (onion). Essential and non-eseential heavy metals were determinated by atomic absorption spectrometry. I monitored the relative frond number, relative fresh weight, chlorophyll and carotenoid contents, guaiacol peroxidase activity and cytogenetic analysis. All samples of tested waters caused growth inhibition, decrease of chlorophyll and carotenoid contents and decline of guaiacol peroxidase activity. Activity of that antioxidant enzyme increased only in ZGOS 4 and 5 samples. Water samples containing heavy metals caused the inhibition of onion root length and morfological changes of root tips such as crochet hooks. Consequently, mitotic index declined and the number of cells in each fase of cell cycle decreased as well. Cytogenetic analysis revealed the highest number of chromosome aberrations in both waste waters and surface water Sutla Prišlin. The most frequent chromosome aberrations as sticky chromosomes, c-mitosis and lagging chromosomes were most probably caused by increased quantities of lead, mercury and chromium in water samples. Results obtained in this work indicate that surface and waste waters contains toxic and genotoxic compounds that may impact aquatic ecosystem but also present potential risk to all living organisms.

• Keywords: fitotoksičnost; Lemna minor; Allium cepa; genotoksičnost
• Keywords (english): phytotoxicity; Lemna minor; Allium cepa; genotoxicity
• Language: croatian
• URN:NBN: urn:nbn:hr:217:826072
• 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
• Created on: 2018-03-05 12:47:33