The Effect of external abscisic acid on some physiological factors and gas exchanges of Lavender (Lavandula angustifolia cv. Organic Munestead) in response to drought stress

In order to study the effects of irrigation and abscisic acid regime on physiological factors and gas exchanges of Lavandula angustifolia CV. Organic Munestead, a pot experiment was conducted as factorial based on randomized complete block design with three replications at Plant Production faculty of Gorgan University of Agricultural Sciences and Natural Resources, during growing season of 2016- 17. The treatments were four levels of irrigation regimes (30-40, 50-60, 70-80 and 90-100 percent field capacity) and Abscisic acid including three levels (0, 15 and 30 Mm/L). The results showed that irrigation regimes increase chlorophyll a, chlorophyll b, chlorophyll a+b, gas exchange and RWC. Abscisic acid had significant effect on all traits except of carotenoid content that except to efficiency of water consumption was Abscisic acid 15 Mm/L, the others were the highest in Abscisic acid 30 Mm/L. Also interaction effect of irrigation regimes and Abscisic acid was significant for all traits except of chlorophyll a+b. Abscisic acid 15 Mm/L spray and irrigation regimes 30-40 percent field capacity increase 25.04 and 38,75 in efficiency of leaf water consumption and efficiency of water consumption, respectively. Generally, Abscisic acid 15 Mm/L application and irrigation regimes 30-40 percent field capacity Introduces the best treatment, due to the lower consumption of water and the use of Abscisic acid in stress conditions, higher levels of Abscisic acid can be achieved in inducing drought tolerance.