Geographic variation of strontium concentrations in orange leaves

Abstract

Very high (>7,000 μg g^‐1 d.w.) strontium (Sr) concentrations in orange leaves from a site in southwestern Florida raised the question of how common were these higher than previously reported levels. Five leaf samples each of which had been collected for nutritional diagnosis at the optimum sampling time at 22 locations in Florida and one each in Texas, Arizona, Mexico, Nicaragua, Brazil, and Argentina, were analyzed for Sr, calcium (Ca), and magnesium (Mg). High Sr levels in the leaves were limited to three sites in a narrow band across Florida between latitudes 27°00’ and 27°30’ N. Levels in the more northern locations tended to be lower (<100 μg g^‐1 d.w.) than at the southern sites. The out‐of‐state and foreign samples contained Sr in the 100 to 400 ug g^‐1 d.w. range reported from California.