nitrogen content and nitrogen reserves in annual leaves and offshoots of apple trees undergoing foliar nitrogen fertilization

Foliar applications of nitrogen (N), when needed, have been used to supplement the fertilization of fruit trees through the soil. However, information on frequency effects, N amount to be applied, and the importance of increasing N content and N reserves in the leaves and offshoots are few. This paper aimed at evaluating the effect of foliar N applications on the N content and reserves in annual leaves and offshoots of apple trees. The study was carried out in an apple trees orchard (Eva cultivar), crop 2007/2008, in the experimental area of the Polytechnic College of Universidade Federal de Santa Maria (UFSM), in the town of Santa Maria, Rio Grande do Sul, Brazil, on a hydromorphic planosol. The treatments consisted of 1 and 2 foliar applications of 0; 1.11; 2.23; 3.31; 4.41; and 5.51g of N plant-1. The results showed that foliar N applications resulted in increased N contents in the whole leaves, especially up to the 8th day after application, but they do not affect N content in the annual offshoots. Nitrogen fertilization via the leaves did not increase the total content of amino acids and proteins in the annual whole leaves and offshoots