Uptake of nitrate‐nitrogen by blueberry plants

Abstract

Kinetic parameters of the uptake of nitrate‐nitrogen (NO₃‐N) by rabbiteye blueberry plants (Vaccinium ashei Reade cv. Tifblue) were studied. Plants were grown in nitrogen (N)‐free nutrient solution for three days and then transferred to nutrient solutions that contained various concentrations of NO₃‐N. The rate of uptake of NO₃‐N was maximal 24 hr after exposure to nitrate at 0.2 mM and lower concentrations, whereas it was maximal after 8 hr at 0.4 mM NO₃‐N. Net uptake of NO₃‐N exhibited saturation‐type kinetics over a range of concentrations of NO₃‐N in the nutrient medium of 0.0125 to 0.2 mM from zero hr to 28 hr. V_max values 8 hr and 24 hr after the start of exposure to NO₃‐N were 1.58 and 1.75 μmol/(g root fresh weight)/hr, respectively.