Effect of water deficit on morphological and physiological parameters of Carum copticum

Ajwan (Carum Copticum L.) is an important plant in Apiaceae family and has many medical uses. In this research، the effects of water deficit stress on growth، yield، compatible metabolite accumulations (proline and carbohydrates) and plant ingredients were studied under controlled conditions in a greenhouse. Water deficit levels included mild stress (90% field capacity)، medium stress (70% field capacity) and severe stress (50% field capacity). In 50% field capacity، the plant didn''t reach to seeding stage. Also، In this study، seed essence of plants under water stress، levels of 70 and 90% field capacity، was obtained by distillation with water and chemical compounds of essence were analyzed by GC/MS method. The statistical results showed significant effects of water stress on growth parameters، seed yield، proline accumulation، carbohydrate accumulation، oil yield and essential oil percentage. The increase of water stress decreased plant height، number of lateral branches، dry weight and seed yield. However، oil yield، oil percentage، proline and carbohydrate contents increased. The highest amounts of proline and carbohydrate at the 50% of field capacity (high stress) and also the maximum essential oil yield and percentage of essential oil at 70% field capacity were observed. Twenty-one chemical compounds were identified in both of the essences of Carum Copticum، and thymol، gamatherpinen and parasimen in each treatment were changed.