Temporal evolution of 137Cs+, K+ and Na+ in fruits of South American tropical species

► Concentrations of 137Cs, K and Na in fruits of lemon (Citrus limon B.) are presented. ► Concentrations of K and Na in fruits of coconut (Cocos nucifera L.) are also showed. ► We investigated the use of 137Cs as a tracer for the plant absorption of macronutrients. ► A model was developed to simulate the temporal evolution of 137Cs, K and Na by fruits. ► This model exhibited close agreement with our results along the fruit development.