Razporeditev in vezavne oblike niklja pri hiperakumulacijskih rastlinah iz rodu Berkheya iz Južne Afrike.

Katona, Kaja (avtor), Vogel Mikuš, Katarina (mentor)

Onesnaženost okolja s kovinami predstavlja velik ekološki in gospodarski problem. V prisotnosti velikih koncentracij kovin, lahko kopenske rastline razvijejo dve strategiji, da se zaščitijo: izključevanje ali akumulacijo in skladiščenje kovin. Nikelj je kovina in v rastlini lahko doseže velike koncentracije. V normalnih tleh se Ni nahaja v koncentracijah od 1 – 450 mg/ kg. V tleh bogatih z Ni pa lahko koncentracija Ni doseže 450 – 26 000 mg/ kg. Hiperakumulatorji lahko vsebujejo več kot 1000 mg Ni na kg suhe mase. Namen naloge je torej raziskati porazdeljevanje in vezavne oblike Ni pri dveh podvrstah rastlinske vrste Berkheya zeyheri, ki je endemična za serpentinska tla v Južni Afriki. Razporeditev Ni na organskem in tkivnem nivoju smo določili z metodami XRF, mikro-PIXE, na celičnem nivoju (topni in netopni del) pa z ekstrakcijo, ICP-MS in XRF. Vezavne oblike Ni v tkivih smo določili z metodo ekstrakcije in tekočinske kromatografije (LC). Rezultati so pokazali, da so pri hiperakumulacijski podvrsti B. zeyheri koncentracije Ni v rastlini večje, kot v tleh. Največja koncentracija Ni pa je bila v listih. Nikelj se pri hiperakumulacijski populaciji kopiči v listih, pri neakumulacijski pa v koreninah. V listih se Ni nahaja v fotosintezno neaktivnih (povrhnjica) in aktivnih (mezofil) tkivih. Na celičnem nivoju pa se Ni nahaja v vakuolah in celični steni. Rezultato LC kažejo, da je večina Ni v ionski obliki oz. kot Ni-citrat.

• Jezik: Slovenski jezik
• Ključne besede: hiperakumulacijske rastline, Berkheya, nikelj, razporeditev Ni, vezavne oblike Ni, organske kisline
• Vrsta gradiva: Magistrsko delo/naloga
• Tipologija: 2.09 - Magistrsko delo
• Organizacija: BF - Biotehniška fakulteta
• Založnik: [K. Katona]
• Leto izida: 2017
• PID: 20.500.12556/RUL-95731
• UDK: 581.5:582.991:669.24:502.174(043.2)
• COBISS.SI-ID: 8817273
• Datum objave v RUL: 21.09.2017

Sekundarni jezik

• Jezik: Angleški jezik
• Naslov: Localization and ligand environment of nickel in hyperacumulating plants from the genus Berkheya from South Africa

Izvleček

Environmental contamination by metals represents a major environmental and economic problem. In the presence of high concentrations of metals, the terrestrial plants may develop two strategies in order to protect themselves. Those strategies are: exclusion or accumulation; and sequestration of metals. Nickel is a metal and can reach a high concentration in the plant. In normal soil Ni is present at concentrations in the range from 1 to 450 mg/ kg. In the Ni-rich soil, the concentration can reach 450 - 26 000 mg/ kg. Hyperaccumulators can contain more than 1 000 mg per kg of dry mass. The purpose of this thesis is, therefore, to explore the distribution and binding forms of Ni in two different subspecies of the plant species Berkheya zeyheri, which is endemic to the serpentine soil in South Africa. The distribution of Ni on organic and tissue level was determined by the following methods: XRF and micro-PIXE, whereas on at the cell level (soluble and insoluble part), this was done by extraction, ICP-MS and XRF. The binding forms of Ni in tissues were determined with the method of extraction and liquid chromatography (LC). The results have shown that in the case of the hyperaccumulating subspecies of B. zeyheri, the Ni concentration is higher than in soil. The highest concentration of Ni was in the leaves. In case of the hyperaccumulating population, Ni is concentrated in the leaves, whereas with the non-accumulation population, it is concentrated in the roots. In the leaves, Ni is located in photosynthetic inactive (epidermis) and as well as active (mesophyll) tissues. On the cellular level, Ni is located in vacuoles and cell wall. LC-MS show that the majority of Ni is present in plant tissues in ionic form or as Ni-citrate.

• Ključne besede: hyperaccumulating plants, Berkheya, nickel, distribution of Ni, binding forms of Ni, organic acids