Antioxidant enzymes activity in ‘Castel Gala’ apple trees after the budbreak inducers application

Abstract

Since antioxidant enzymes activity affects the end of dormancy stage, it is important to understand the responses given by antioxidant enzymes and their roles in budbreak induction in temperate fruit trees. This research aimed at evaluating the antioxidant enzymes activity at the end of budbreak stage after the inducers application to ‘Castel Gala’ apple trees and their performance in budbreak and blooming. Seven treatments were carried out: Erger® 3% + calcium nitrate 5%; Erger® 5% + calcium nitrate 5%; Erger® 7% + calcium nitrate 5%; garlic extract (GE) 5% + mineral oil (MO) 2%; GE 10% + MO 2%; GE 15% + MO 2%; and the control. Buds were collected one, four and seven days after the application (DAA) of budbreak inducers, and activity of the following enzymes was determined by: superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX). Besides that, hydrogen peroxide was quantified. Percentages of budbreak and blooming were evaluated at 32th, 40 th, 45 th and 52 th DAA. The results showed that SOD activity had increased as the dormancy stage reached its end. CAT activity was influenced by the application of budbreak inducers. It decreased significantly throughout the experiment in the most efficient treatment. Percentages of budbreak (61.85%) and blooming (25.44%) showed the highest efficiency in the treatment with Erger® 7% + calcium nitrate 5%, which was the inducer with the highest potential in ‘Castel Gala’ apple trees