Effect of abscisic acid exogenous application on apple trees antioxidant metabolism and photosynthesis

CASTRO, ANDREA; SPERA, NAZARENA; CURETTI, MARIELA; COLAVITA, GRACIELA

Villa Rica

Congreso; XII Reunión de Biología Vegetal; 2019

Chilean Society of Plant Biologists

Fruit trees are frequently exposed to adverse environmental conditions which affect its optimal development. Abscisic acid (ABA) is a hormone involved in abiotic stress responses in plants. In apple trees, ABA has been reported as an antioxidant substances promoter. However, ABA also induces stomatal closure which may affect photosynthesis. Our objective was to determine the effect of ABA applications on ?Granny Smith? apple trees (Malus domestica Borkh.) on antioxidant metabolites production and the effect on photosynthesis and vegetative development. ABA treatments consisted in three applications of ABA 400 ppm on five plants during three months since December to February. Five untreated plants were left for control. In leaves tissues, no significant differences (p≤0.05) were found in lipid peroxidation, antioxidant capacity and total polyphenols. ABA applications decreased 6% photosystem II (PSII) maximum quantum efficiency but did not affect chlorophylls and carotenoids contents. Stomatal conductance in treated leaves decreased from 169 to 64 μmol H2O m-2 s-1 with a reduction of net photosynthesis (Pn). Control leaves Pn was 16.8 μmol CO2 m-2 s-1, while in, treated leaves, was 8.6 μmol CO2 m-2 s-1. Consequently, specific foliar mass and foliar area decreased in control and ABA treated leaves 11% and 16%, respectively. ABA application did not promote changes in tissues antioxidative state but it induced stomatal closure and Pn decrease, which negatively affected vegetative development. We Thank Ing. Agr. Laura Vita And Ing. Agr. Valeria Blackhall, For Their Assitance With Various Aspects Of This Study. Research supported by project A-131, Universidad Nacional del Comahue and CITACC, UNComa-CONICET.