Evaluation of drought resistance of Lavandula angustifolia and L.stoechas

To understand the drought resistance mechanism of two species (Lavandula angustifolia and L.stoechas), changes of physiological and biochemical indexes were investigated under light (LS), moderate (MS) and severe (HS) drought stress for 0, 10, 20, 30 and 40 days through controling soil volumetric woisture content with negative pressure water supplying and controlling devices. The results showed that with the increasing of drought stress intensities and stress periods, the relative water content (RWC) of two species displayed a reduction trend. Under severe drought stress, the decrease amplitude was significantly increased after 40 d, the RWC decreased to 30.08% and 25.27%, while the RWC of L.angustifolia was the lowest. Contrary leaf relative electrolytic leakage (REC), soluble sugar (SSC) and MDA contents followed an increasing trend. The REC of L.angustifolia increase amplitude beyond to 400% under severe drought stress and was significantly higher than that of L.stoechas. The MDA content of L.angustifolia was also higher than that of L.stoechas. Meanwhile, SOD and CAT activities firstly elevated and then declined. Compared to the L.angustifolia, the RWC, SOD and CAT activities of L.stoechas were higher, but the REC, SSC and MDA contents of L.stoechas were lower. Overall, L.stoechas exhibited a stronger ability to tolerant drought stress than L.angustifolia.