Manganese (Mn) is a microelement, but it is also a heavy metal whose excess may have a toxic effect on plants. The aim of the study was to evaluate the effect of an application of increasing Mn concentrations added to a nutrient solution on the content of macro- and micronutrients in tomato leaves (Lycopersicon esculentum Mill., cv. Alboney F1 and Emotion F1). Plants were grown in rockwool using a nutrient solution with the following content of manganese (mg dm-3): 0.06; 0.3; 0.6; 1.2 (experiment I, in 2008-2011); 2.4, 4.8; 9.6; 19.2 mg dm-3 (experiment II, in  2012) – designated the symbols Mn-0; Mn-0.3; Mn-0.6; Mn-1.2; Mn-2.4; Mn-4.8; Mn-9.6; Mn-19.2. The nutrient solution used for plant fertigation had the following chemical composition (mg dm-3): N-NH4 2.2, N-NO3 230, P 50, K 430, Ca 145, Mg 65, Cl 35, S-SO4 120, Fe 2.48, Zn 0.50, Cu 0.07, pH 5.50, EC 3.00 mS cm-1. Manganese significantly influenced the content of other macro- and microelements in leaves. In variant Mn-0, the content of  N, P, K, Ca, Mg, Mn decreased, while that of of Fe, Zn, Cu was higher; in Mn-1.2, the content of N, Mg, Fe, Zn decreased and that of P, K, Ca, Mn increased compared with the variants which ensured optimal yielding. In the range of manganese nutrition from Mn-4.8 to Mn-19.2, N, K, Mg, Fe, Zn, Cu were lower and the content of P and Mn was higher (above optimal). The cultivar significantly modified the nutrient status of plants concerning nitrogen (for Mn-9.6 and Mn-19.2), phosphorus (for Mn-1.2 and Mn-2.4), potassium (for Mn-4.8 and Mn-9.6), calcium (for Mn-0, Mn-1.2, Mn-9.6), magnesium (Mn-0 and Mn-0.6), iron (Mn-0, Mn-0.3, Mn-9.6), manganese (Mn-0.3, Mn-1.2, Mn-2.4, Mn-19.2), iron (Mn-0, Mn-0.3, Mn-9.6), zinc (Mn-0.6, Mn-1.2, Mn-2.4, Mn-9.6) and copper (Mn-2.4, Mn-4.8, Mn-9.6, Mn-19.2). Briefly, both deficit or excess manganese nutrition could induce disorders in the uptake of other nutrients, which may influence plant yielding.

20.1.2015