Variation of amino acids in Prunus persica cultivars leaves with regard to leaf age

The central role of amino acids in cellular and plant physiology is of current interest. Information related to the implication of amino acids during leaf age is still scarce. This study examined changes in the profile of amino acids extracted from leaves of five peach cultivars (‘Early Maycrest’, ‘Sweet Cap’, ‘O'Henry’, ‘Flordastar’, and ‘Rubirich’) grown in the region of Sidi Bouzid, central-western Tunisia with respect to leaf age. Seventeen amino acids, aspartic acid (Asp), serine (Ser), glycine (Gly), proline (Pro), tyrosine (Tyr), valine (Val), methionine (Met), cysteine (Cys), tryptophan (Trp), leucine (Leu), phenylalanine (Phe), isoleucine (Ile), lysine (Lys), glutamic acid (Glu), arginine (Arg), alanine (Ala), and histidine (His) were quantified. Significant variations were observed for Asp, Glu, Ser, Gly, Ala + Arg, Pro, Val, Ile + Trp, and Lys in relation to the leaf age. On average, young leaves (106.48–142.18 mg g−1 DW) contained higher amounts of most amino acids than mature leaves (97.33–110.27 mg g−1 DW). Approximately identical contents of amino acids were found in the different cultivars. In conclusion, P. persica leaves are a very rich source of amino acids (about 10% DW), and therefore deserves further investigation for their potential application in the nutraceutical, food, feed, and pharmaceutical industries.