Effect of root imbibition with selenium and iodine on antioxidant compounds in tomato (Solanum lycopersicum L.) crop

The use of trace elements such as iodine and selenium in agriculture is gaining great importance due to the benefits in plants before different types of biotic or abiotic stress. This research aimed to evaluate the seedling root priming with Na2SeO3 (0, 0,5, 1, 2, 3 mg L-1) and KIO3 (0, 100, 150, 200, 250 mg L-1) on the antioxidant compounds of tomato (Solanum lycopersicum L.) fruits and leaves. The crop was established under greenhouse conditions in 10-L polyethylene containers containing peat moss and perlite 1:1 (v/v), in a randomized complete block experimental design with a 52 factorial arrangement. In the fruits, the Na2SeO3 influenced the GHS, flavonoids, lycopene and β-carotene contents, while the KIO3 influenced the GHS, vitamin C and lycopene contents. The KIO3-Na2SeO3 interactions affected the GSH, phenols, flavonoids, lycopene and β-carotene contents in fruits. In the leaves the GHS content increased with the Na2SeO3, while the GSH, flavonoids, and chlorophyll contents increased with the KIO3 factor and KIO3-Na2SeO3 interactions. The evaluated enzymes in fruits and leaves decreased with the both the KIO3 and Na2SeO3 concentrations. The Na2SeO3 influenced the hydrophilic compounds by ABTS and DPPH, while the KIO3 influenced the hydrophilic compounds by ABTS. In the leaves, the KIO3 influenced the lipophilic compounds by ABTS. The KIO3-Na2SeO3 interactions influenced the hydrophilic compounds by ABTS in both the fruits and leaves. Seedling root imbibition in KIO3 and Na2SeO3 is a method that implemented in the tomato crop presents interesting aspects in the increase of the antioxidant capacity and the non-enzymatic compounds, such as vitamin C, phenols, flavonoids and GSH contents. However, this method presented an inhibition in the antioxidant enzymes.