Water Stress-Induced Alterations in Essential Oil Content and Composition of Sweet Basil

ABSTRACT Mild and moderate plant water stress increased sweet basil leaf essential oil content and altered oil composition. After 21 d of plant water deficit, the oil content of leaves increased from 3.1 to 6.2 μl.g1 leaf dry wt. as xylem water potential (ψ) decreased from −0.30 to −1.12 MPa. Significant decreases in leaf dry weight and stem dry weight were observed as plant water deficit increased. Only leaf area from plants subjected to a mild water deficit (-0.68 MPa) was not significantly reduced compared to the control, non-stressed plants. Water stress altered the oil composition (both as a relative percentage of total oil and μl.g1 leaf dry weight). Linalool and methyl chavicol increased as water stress increased, while the relative proportion of sesquiterpenes decreased.