(100-103) Effect of boron application on the physiological and antioxidant response in highbush blueberry (Vaccinium corymbosum L.) subjected to aluminum stress
Aluminum (Al) toxicity negatively effects the growth and production of blueberries in acidic soils, including physiological and biochemical aspects, decreasing the photosynthetic activity, altering in phenolic and flavonoids metabolism, increased of the oxidative stress, and enzyme activity. Boron is an essential nutrient for plant growth and development, and it has been suggested in the mitigating of Al phytotoxic. We used two Al-contrasting genotypes [cv. Cargo (Al-resistant) and cv. Star (Al-sensitive)] in a Hoagland solution at pH 4.5 for 72h, with 200 µM of Al, applied as Al3Cl. Also, we used foliar boron (B) applications at concentrations of 0 (control), 200, 400, and 800 mg L-1. Leaf and root samples were collected at 0, 24, 48, and 72h after application. Net photosynthesis (Pn), antioxidant activity (AA), phenolic compounds (PhC), flavonoids (FV), lipid peroxidation (LP) and the activity malate dehydrogenase (MDH) were evaluated. The results indicated significant differences (P≤0.05) in treatment, time, and their interaction. LP decreased with B application in Cargo leaves at 200 and 400 mg L-1, and in Star leaves at 800 mg L-1. In Star roots, LP decreased significantly with 800 mg L-1 at 72h. PhC and FV increased in Cargo leaves during the 24 and 48h with 400 and 800 mg L.1, while in Star leaves, PhC increased at 48 and 72h with 800 mg L-1. As for MDH and Pn, it was observed that B application improved MDH and Pn in Star at 48 and 72h with 400 and 800 mg L-1, while Cargo showed an increase at 24, 48, and 72h with 200 mg L-1. These results suggest that B application had beneficial effects on