Ferrous iron, the physiologically active form (1) inserted into phytoferritin is highly susceptible to oxidation by oxygen and can form superoxide ion (O₂^·-). Catalytic Fe(II) may interact in turn with O₂^·- trough a Fenton reaction to yield hydroxyl radicals (^·OH). Both free radicals are extremely cytotoxic and promote oxidative damages (2).

This study presents influences of iron accumulation in leaves of Astragalus onobrychis var. chlorocarpus (Gris.) Stoj. et Stef. (Leguminosae) (3) under drought stress on increase of O₂^·- and ^·OH, as promotion of lipid peroxidation (LP). After wet digestion, levels of iron in all samples were determined by AAS, using Perkin Elmer 1100 atomic absorption spectrophotometer with graphite cuvette. Superoxide radical was studied by the inhibition of adrenaline autooxidation. Hydroxyl radical was measured by the inhibition of deoxyribose degradation. The lipid peroxidation was measured by the thiobarbituric acid method, as equivalent amounts of malonyl-dialdehyde (MDA). The all values are expressed as mean ± standard error. Some results are presented in Table 1.

The large increase of iron in leaves of Astragalus onobrychis var. chlorocarpus (Gris.) Stoj. et Stef. (Leguminosae) under drought stress influences on increase of oxidative damages trough an increase of O₂^·-, ^·OH and LP.

References

1. Chasteen N.D. and Harrison P.M. (1999): J. Struct. Biol. 126, 182.
2. Niyogi K.K. (1999): Annu. Rev. Plant Physiol. Plant Mol. Biol. 50, 333.
3. Miladinović D., Đujić I. and StankovićS. (1997): Functional Metals in Growing Wild Plants, Fourth International Conference on the Biogeochemistry of Trace Elements, June 23-26, Berkeley, USA.