Translocação e compartimentalização de Zn aplicado via ZnSO4 e ZnEDTA nas folhas de cafeeiro e feijoeiro

Two experiments were conducted aiming to evaluate translocation and compartmentation of ZnSO4 and ZnEDTA applied on leaves of coffee and bean seedlings previously grown under Zn sufficiency or deficiency in nutritive solution in greenhouse. The treatments applied were 14mmol L-1 ZnSO4, ZnEDTA and test without zinc applied on leaves. In both species, ZnSO4 was more retained on leaf cuticle, indicating cuticular zinc retention to be an important barrier in its uptake. The nutritional status of bean plants had a significant effect upon zinc utilization when it was applied on leaves. Bean plants enhanced zinc acquisition more than coffee seedlings. Plants grown in zinc deficient solution showed a higher efficiency in ZnEDTA translocation. Coffee seedlings grown in zinc deficient solution showed higher zinc retention in the stem, suggesting high Zn2+ affinity with negatively charged groups in the conductive vessels.