Lavender sensitivity to water stress: Comparison between eleven varieties across two phenological stages

Abstract

Essential oils from Lavandula angustifolia Mill. and Lavandula x intermedia Emeric x Loisel composed of concentrated terpene mixtures, and are highly produced due to their economic value. In the Mediterranean area, the production is threatened by the increasing frequency and intensity of drought events, leading to the loss of crops. Thus, we aimed to evaluate the response to water stress and the tolerance of the main French cultivated varieties of L. angustifolia and L. x intermedia during flowering period, based on the response of their primary metabolic traits (e.g. growth, photosynthesis, stomatal conductance) and specialized metabolic traits (terpene storage and emissions related to the plant defense system). Two treatments were applied: a control where plants received 300 mL every day (≈75% of substrate field capacity) and a stress where plants received 100 mL every two days (≈25% of substrate field capacity). Our results showed that both species featured a drought-tolerant strategy to cope with water stress with a more competitive strategy in L. angustifolia. Water deficit modified the amounts of stored terpenes in both species which could be economically harmful for the sector related to essential oil production. Moreover, some compounds such as bornyl acetate were highlighted as potential defense compounds. The study also highlighted that the varieties ‘Rapido’ (L. angustifolia), arecent variety developed in France, and ‘Sumian’ (L. x intermedia), could be the best candidates to cultivate under intense drought.