Effect of species and variety on the content of macroelements and micronutrients in lettuce

The nutritional importance of fresh lettuce lies in the high content of bioactive substances among which macroelements and micronutrients take a special place. We studied 10 lettuce varieties from two species: Lactuca sativa L. (var. capitata and var. foliosa) and Cichorium intybus (var. foliosum). The varieties were grown on a fertile limeless chernozem soil in the summer-fall period under the conditions of the moderate continental climate of the Vojvodina Province (northern Yugoslavia). The experiment did not receive mineral fertilizers and chemical protection. but it was a part of a regular crop rotation. Macroelements and micronutrients were analyzed by conventional methods, the contents of P, K, Ca and Mg were given in g/kg of fresh matter and the contents of Cu, Zn and Fe in mg/kg of fresh matter. The lettuce varieties had increased contents of P, K and Ca, Mg, Cu and Fe, the chicory varieties had increased contents of Zn and Mn. Inclusion of lettuce in human diet may cover a large part of the daily requirement for K, Cu, Fe and Mg. This reiterates not only the importance of lettuce in the group of yellow-green vegetables but also the necessity of a year-round production of lettuce.