Differential responses of oat genotypes: oxidative stress provoked by aluminum
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The phytotoxic effects of aluminum and the mechanisms of genetically-based Al tolerance have been widely investigated, as reported in many papers and reviews. However, investigations on many Al-sensitive and Al-resistant species demonstrate that Al phytotoxicity and Al-resistance mechanisms are extremely complex phenomena. The objective of the present study was to analyze the effects of aluminum on the activity of antioxidant enzymes such as catalase (CAT), superoxide dismutase (SOD), and ascorbate peroxidase (APX). Also was evaluated the lipid peroxidation, H2O2 content, levels of ascorbic acid (ASA), non-protein thiols (NPSH) and Al content in three genotypes of oat, Avena sativa L. (UFRGS 930598, UFRGS 17, and UFRGS 280). The genotypes were grown in different concentrations of Al ranging from 90 to 555 μM for 5 days. The antioxidant system was unable to overcome toxicity resulting in negative effects such as lipid peroxidation and H2O2 content in UFRGS 930598. The results showed that UFRGS 930598 was the most sensitive genotype. UFRGS 17 and UFRGS 280 were more resistant to Al toxicity. These results suggest that UFRGS 17 has mechanisms of external detoxification and UFRGS 280 has mechanisms of internal detoxification. The different behavior of enzymatic and non-enzymatic antioxidants of the genotypes showed that aluminum resistance in UFGRS 17 and UFRGS 280 may be related to oxidative stress.
KeywordsAvena sativa Superoxide dismutase Hydrogen peroxide Ascorbate peroxidase Catalase Aluminum content Oxidative stress
The authors wish to thank the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Coordenação e Aperfeiçoamento de Pessoal de Nível Superior (CAPES), and Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul (FAPERGS).
- Creissen G, Fimin J, Fryer M, Kular B, Leyland N, Reynolds H, Pastori G, Wellburn F, Baker N, Wellburn A, Mullineaux P (1999) Elevated glutathione biosynthetic capacity in the chloroplasts of transgenic tobacco plants paradoxically causes increased oxidative stress. Plant Cell 11:1277–1292CrossRefPubMedGoogle Scholar
- De Biasi MG, Astolfi S, Acampora A, Zuchi S, Fonzo V, Santagelo E, Caccia R, Badiani M, Soressi GP (2003) A H2O2-forming peroxidase rather than a NAD(P)H-dependent O2 •-synthase may be the major player in cell death responses controlled by the Pto-Fen complex following fenthion treatment. Funct Plant Biol 30:409–417CrossRefGoogle Scholar
- Federizzi LC, Chacón CDS, Milach SCK, Pacheco MT (2000) Variabilidade genética e herança da tolerância à toxicidade do alumínio em aveia. Pesqui Agropecu Bras 35:1797–1808Google Scholar
- Mc Cord JM, Fridovich I (1969) Superoxide dismutase: an enzymic function for erythrocuprein (hemocuprein). J Biol Chem 244:6049–6055Google Scholar