Physiological and metabolic responses to aluminum toxicity reveal differing resistance mechanisms to long-term exposure in highbush blueberry cultivars

Aluminum (Al) toxicity is a major environmental stress that affects the growth and development of plants in acid soils. Plants have developed different mechanisms and strategies of Al resistance based on the biosynthesis of organic compounds and the formation of non-phytotoxic complexes with Al. In this study we use three cultivars traditionally cultivated of highbush blueberry (Vaccinium corymbosum L., Brigitta , Star , and Duke ) and two cultivars from the USA ( Camelia and Cargo ) that were recently introduced in southern Chile. Physiological and biochemical parameters were evaluated on plants grown at 0 and 200 µM Al in Hoagland solution (pH 4.5) for 0, 7, 14, and 21 days. We found that the Al concentration increased in roots and shoots in all cultivars and that the relative growth rate was reduced only in shoots of Star plants, an Al-sensitive cultivar. Photosynthetic parameters were reduced under Al treatment only in Star and Brigitta . The concentration of photosynthetic pigments was reduced in Star , but increased in Cargo and Brigitta under Al toxicity. Duke had a higher concentration of sugars and polyphenols, increased antioxidant activity, and low lipid peroxidation in leaves under Al treatment. The levels of ascorbate (ASC) and dehydroascorbate (DHA) increased in Camellia leaves and Duke roots. The ASC/DHA ratio in roots increased in Star , and Camellia , but decreased in Duke and Brigitta leaves in the Al treatment. Cultivars Cargo and Brigitta increased oxalate exudation from roots under Al-toxicity, whereas Star had low oxalate exudation. The results suggest a possible strategy related to internal detoxification via carbohydrates and phenolic compounds to reduce the long term toxic effect of Al in Duke , Cargo , and Camellia cultivars of V. corymbosum under acidic conditions. © 2022 Elsevier B.V., All rights reserved.

cultivars, star, increased, brigitta, duke, under, toxicity