Changes in Secondary Metabolites Content and Antioxidant Enzymes Activity in Leaves of Two Prunus avium L. Genotypes During Various Phenological Phases

In addition to its fruit, the sweet cherry (<i>Prunus avium</i> L.) has other parts that can be used as a source of compounds with beneficial biological activity. The content of these metabolites is affected by different inner and outer factors, often as a response to plant defense against various stresses. Leaves of two <i>P</i>. <i>avium</i>. genotypes, Kordia and Regina, grafted on the same rootstock, were analyzed from trees grown in orchards in six different phenological phases for two years. The content of several groups of phenolic compounds, lipid peroxidation, antioxidant activity of the extracts, and enzyme activity were observed via colorimetric methods on a UV/Vis spectrophotometer. The obtained data showed that the content of metabolites and other parameters in these two genotypes are dependent on the term of harvest, as well as environmental conditions, mainly temperature, but sunshine duration and rainfall also had a certain effect on the compounds in the leaves of Kordia and Regina. Even though the differences between these genotypes were not always significant, it is important to consider the right time to harvest the leaves of the sweet cherry, as their content could vary as a result of the reaction to various other conditions and could reflect the resistance of the chosen genotype.