Gypsum application ameliorates morphological and photochemical damages provoked by Al toxicity in Vaccinium corymbosum L. cultivars

BACKGROUND: By acidity, Al³⁺ available form increases, being toxic for plants. Calcium amendments are widely used as an agronomic practice to reduce this effect. OBJECTIVE: To determine the gypsum application effect on leaf morphological and physiological features on three highbush blueberry cultivars growing in acid soil and toxic Al level. METHODS: Legacy and Brigitta, Al-resistant and Bluegold, Al-sensitive were grown in acid soil with 48% Al saturation and three gypsum concentrations (0.7, 1.4, and 2.8 g CaSO4kg^-1) for 30 days. Chlorophyll a fluorescence measurements, photosynthesis, and photoprotective pigments were analyzed. Samples of leaves and roots were harvested, and Al, Ca, and S concentrations, antioxidant activity (RSA), lipid peroxidation (LP), and leaf anatomy were determined. RESULTS: Gypsum decreased leaves and roots Al concentration in all cultivars. Higher Ca leaves concentration in cultivars was observed compared to roots under gypsum treatment. Aluminum damages were observed in leaf thickness, improving anatomic features in cultivars by gypsum as well as a reduction of LP without changes in RSA. Chlorophyll levels changed differentially according to the cultivar and CaSO4 dose, while antheraxanthin was higher in Legacy with gypsum. The Principal Component Analysis (PCA) scores plot showed that PC1 separated Brigitta from Legacy-Al resistant, while PC2 helped to discriminate Bluegold Al-sensitive cultivar with gypsum treatment from the rest of the samples, including Bluegold without gypsum. CONCLUSIONS: Gypsum amendment ameliorates leaf morphology alterations as well as photochemical and biochemical damages in highbush blueberry under Al-toxicity, being cultivar-dependent. The morphological parameters can be important features as Al-resistance anatomical markers in highbush blueberry.