Abstract

MEDRANO-MACIAS, Julia et al. Effect of iodine application on antioxidants in tomato seedlings. Rev. Chapingo Ser.Hortic [online]. 2016, vol.22, n.2, pp.133-143. ISSN 2007-4034.  https://doi.org/10.5154/r.rchsh.2015.12.025.

Iodine is a beneficial micronutrient, but its metabolic function is still unknown. The aim of this study was to evaluate the effect of iodine application on biomass and antioxidant concentration in tomato seedlings. Iodine was applied in the form of iodide (I-) and potassium iodate ( IO3-), at concentrations of 1 μM daily and 100 μM biweekly, directly to the substrate or by foliar application to tomato var. Río Grande seedlings under greenhouse conditions. The effect of iodine on enzymatic antioxidants (superoxide dismutase, catalase, ascorbate peroxidase, and glutathione peroxidase), as well as the concentration of non-enzymatic antioxidants (ascorbate, glutathione, and total phenols) was analyzed. No treatment with I- or IO3- had a negative effect on seedling biomass. In addition, the biweekly I- treatments both by foliar and substrate application, as well as the daily IO3- and I- treatments via foliar application showed a 54 to 86 % decrease in superoxide dismutase enzymatic activity, without showing changes in the other enzymes. On the other hand, in both cases with daily I- foliar application, the non-enzymatic antioxidant concentrations for ascorbate and glutathione increased by 22 and 85 %, respectively. Phenolic compounds showed no changes in the different treatments.

Keywords : biofortification; oxidative stress; enzymes; ascorbate; glutathione.