L-tryptophan affects the essential oil of navel orange under various growing regions

Abstract

Abstract Essential oil (EO) of navel orange had anticancer and antimicrobial activities. l -tryptophan and growing regions play important roles in physiological processes of navel orange EO. The application of l -tryptophan under different growing regions is one way of scientific research that has the potential to increase the EO production, so, the aim of this trial was to evaluate the EO isolated from young shoots and peels of navel orange trees under l -tryptophan treatments in West and Upper Egypt. The experiments were conducted at the two Citrus farms located in West and Upper Egypt. Selected trees were subjected to l -tryptophan doses at 0, 200 and 400\u202fmg/L in both regions. The EO of young shoots and peels was isolated by hydro distillation method (HD), then, analyzed by GC and GC/MS equipments. Data were statistically analyzed using ANOVA-2. The EO percentages and constituents of young shoots or peels were significantly affected due to l -tryptophan doses in both regions. The major component of young shoot EO was sabinene while it was limonene of peel EO. The treatment of 400\u202fmg/L ( l -tryptophan) resulted in the greatest amounts of EO (%), sabinene and limonene in west and Upper Egypt. The application of l -tryptophan caused different variations in all chemical classes (MCH, MCHO, SCH and SCHO) of young shoots and peels EO in both regions. l -tryptophan levels produced positive variations on essential oil composition of navel orange trees grown in West and Upper Egypt.