The Impact of Drought on the Physiological Characteristics of Half-Sib Lines of Turkey Oak (quercus Cerris L.)

Two half-sib lines of Turkey oak (Quercus cerris L.) (C1 and C2) were subjected to different treatments in semi-controlled conditions: optimal soil moisture - control (K), drought followed by recovery after the restoration of the optimal soil moisture (T1) and the treatment of constant drought (T2). Changes in the physiological parameters related to the process of photosynthesis were examined in correlation with the applied treatments. Treatment T2 was influenced to a significant reduction in the intensity of photosynthesis, stomatal conductance and instantaneous water use efficiency, as well as to a significant increase in the intercellular CO2 concentration in both half-sib lines. In relation to control, treatment T2 did not lead to a significant variation in the maximum photochemical efficiency in the examined half-sib lines. In treatment T1, the second half-sib line (C2) showed better ability to recover the intensity of photosynthesis and stomatal conductance after re-watering, while using the same treatment before recovery, water was used more efficiently compared to the first half-sib line (C1). The results of the study indicate specific adaptive predispositions of the examined half-sib lines in relation to drought stress and recovery.