Effect of foliar calcium chloride treatment on the level of chlorogenic acid, β-carotene, lutein and tocopherols in lettuce (Lactuca sativa L.)

Abstract

The aim of the presented study was to determine the effect of foliar application of CaCl₂ on the level of β-carotene, lutein, tocopherols and phenolic compounds in the leaves of lettuce cv. Omega (Lactuca sativa L.). The experiments were conducted in the greenhouse of the Faculty of Cultivation and Fertilisation of Horticultural Plants, University of Life Sciences in Lublin. During the growing period, 7 and 14 days before harvest, the plants were treated with a solution of CaCl₂ with concentrations of 0.1 M and 0.2 M. Plants sprayed with water were the control treatment in the experiment. Analyses were performed on whole leaves and the blade without midrib. The obtained results indicate that the leaves of lettuce cv. Omega are a good source of phenolic compounds, carotenoids and tocopherols. The dominant carotenoid in lettuce cv. Omega was β-carotene. Foliar application of CaCl₂ on the plants did not have any significant effect on the level of β-carotene and lutein in the whole leaves. The contents of tocopherols, total phenolic compounds and chlorogenic acid were dependent on the concentration of CaCl₂. The application of 0.1 M CaCl₂ solution in the plants resulted in a decrease in the level of total phenolic compounds and chlorogenic acid, and an increase in tocopherol content. However, the treatment of the plants with 0.2M CaCl₂ solution caused a lowering of the concentration of tocopherols and an increase in the content of chlorogenic acid and total phenolic compounds.