پارامترهای تبادلات گازی و عملکرد فلورسانس کلروفیل نهال‌های تحت تنش خشکی بلوط اوری (Quercus macranthera F&M) در استان گلستان

     This study was investigated the gas exchange parameters and Chlorophyll fluorescence yield in Iranian oak (Quercus macranthera F & M) seedling under drought stress in Golestan Province. For this aims, 2 years old of Iranian oak exposed (Quercus macranthera F & M) seedling from Golestan province population exposed to three soil moisture regimes (control, any drought stress (95% field capacity), medium drought stress (60% field capacity) and severe drought stress (% 25 FC) for 45 days’. The gas exchange parameters, water relations and chlorophyll fluorescence were measured. The results showed that photosynthesis, transpiration, stomatal conductance, Fv/Fm, YII and water potential of severe drought stress treatment after 15 days were significantly lesser compared to control treatment. In general Iranian Oak seeding after 15 days in order to avoid of water desiccation in severe drought treatment decreased the gas exchange parameters (photosynthesis, transpiration, stomatal conductance) chlorophyll fluorescence (Fv/Fm and YII) in compare with control treatment. Also using of tolerance water desiccation strategy by Q.macranthera led to after 30 and 45 days, the gas exchange parameters (photosynthesis, transpiration, stomatal conductance) and chlorophyll florescence fluorescence (Fv/Fm and YII) of severe drought treatment hasn’t change compare to its 15 days. According to our findings, it can be concluded Iranian Oak call successfully pass the drought stress using avoidance and tolerance strtegies.