INSTITUTO DE FISIOLOGIA VEGETAL
Unidad Ejecutora - UE
congresos y reuniones científicas
Role of nitric oxide on lipid peroxidation in wheat plants growing under different zinc availability
AGUSTINA BUET; GUILLERMO E. SANTA MARÍA; MARCELA SIMONTACCHI
Congreso; VII Meeting of the SFRBM South American Group; 2011
SFRBM South American Group
Zinc (Zn) is an essential nutrient for the normal growth of plants and its deficiency is widespread in cereals. Nitric oxide (NO) is a bioactive molecule endogenously synthesized in plants with participation in biotic and abiotic stress responses. In this work wheat (Triticum aestivum, var. Chinese spring) plants were grown in modified Hoagland solution with or without 2 mM Zn provided as ZnSO4. After 17 days of development plants exhibit no changes in either total biomass or shoot/root quotient, and no visible Zn deficiency symptoms were detected. However, in roots total Zn measured by atomic absorption was 123±16 and 19±4 nmol/g FW, for the control and the Zn-starved group, respectively. Shoot Zn concentrations were 134±14 and 34±5 nmol/g FW, for control and Zn deficient groups, respectively. Total Fe content in shoots or roots was not affected by Zn-supply. In order to study the effect of an NO donor on the pattern of Zn accumulation, plants were exposed during 17 days to 100 µM S-nitrosoglutathione (GSNO) added to the nutritive solution. Addition of GSNO decreased 48% and 30% the concentration of Zn in roots and shoots of control plants, respectively, while no changes were observed in plants deprived of Zn as a consequence of NO exposure. In turn, no differences in lipid peroxidation, as evaluated by EPR spin trapping, between full supplemented and Zn starved plants were observed. As expected a positive effect over lipid peroxidation was found in control plants exposed to NO. A decrease of 40% in lipid radicals was found in roots of plants exposed to GSNO, and a decrease of 25% was observed in shoot as compared to plants without the NO donor. This pattern of changes in lipid peroxidation was not observed in Zn deficient plants where GSNO did not exert a protective effect. The lack of effect of the NO donor, blocking the lipid peroxidation in Zn-starved plants, suggests that exogenously added NO is being consumed by other pathways in these plants. In plants growing in a complete medium a NO supplementation lead to alterations in Zn concentration in the whole plant, while a lower extent of lipid peroxidation was observed.