Effect of irrigation depth on biomass production and metabolic profile of Lippia alba (linalool chemotype) essential oil

Abstract

Water is a limiting factor in agricultural production. In the cultivation of aromatic plants, abiotic factors, such as water deficit, influence the yield and composition of essential oils. Lippia alba, linalool chemotype, is an aromatic species originally from South America in domestication, and it can be used in the cosmetics industry to develop natural products, such as flavorings, fragrances, and perfumes. So far, the effect of water deficit on the agronomic characteristics and the species' essential oil composition has not been evaluated. In this work, total aerial dry matter production, total leaf dry matter production, essential oil production, and chemical composition of the essential oil from the leaves of selected clones of L. alba were evaluated under four different irrigation depths, using an organic production system during four cutting cycles of 90 days. Nineteen compounds were detected in the essential oil of L. alba. The irrigation treatments altered the relative proportions of the compounds linalool, geranial, β-elemene, and germacrene D. The highest total biomass production of the aerial part was obtained with the 125% of the reference evapotranspiration (ET0) at 180 (second cut) and 270 (third cut) days after formation pruning. The irrigation depths of 100% and mainly the 125% ET0 at 180 days (second cut) favored the total dry matter production of leaves in Lippia alba, chemotype linalool, and the essential oil production. In general, a moderate water deficit generated an adjustment in the use of water resources with increased the essential oil production, in particular the linalool compound.