Kinetic variables related to potassium absorption efficiency in Vaccinium sp. cultivars

Blueberry (Vaccinium sp.) cultivars may exhibit different kinetic variables related to potassium (K) absorption. Thus, the aim of this study was to identify blueberry cultivars (Vaccinium sp.) with greater efficiency in K absorption and use. Eight blueberry cultivars (Climax, Bluegem, Florida, Sharpblue, Biloxi, Emerald, Jewel, and Misty) were acclimatized in a half-strength Hoagland nutrient solution, containing 50% of the macro- and micronutrient concentrations of the original formulation, and evaluated during a 102-h kinetic assay. Kinetic parameters, K absorption efficiency, and the morphological, physiological, and biochemical characteristics of the plants, as well as the nutrient content in the tissues, were determined. The cultivars differed in terms of K absorption and utilization. Emerald stood out for its greater root growth, higher biomass accumulation, and superior photosynthetic and antioxidant performance, associated with low Michaelis-Menten constant (Km) and higher influx, indicating high absorption efficiency under low K availability. Climax and Florida showed higher maximum absorption rate (Vmax) values and greater influx under conditions of higher nutrient availability, demonstrating a better response when K is more available in the soil. Misty and Sharpblue stood out for their higher chlorophyll content and greater photosynthetic efficiency associated with K use. Therefore, Emerald and Misty are more promising for environments with limited K, while Climax and Florida tend to excel in areas with greater supply of this nutrient. These results support the selection of more K-efficient blueberry cultivars, contributing to genetic improvement programs, the rational use of fertilizers, and more sustainable blueberry production.