Impact of drought stress on water potential and gas exchange parameters in Macedonian oak (Quercus trojana P.B. Webb.) seedlings

The increase in the duration and severity of summer droughts due to global climate change will adversely affect forests, and it is very important to examine the drought stress that trees are exposed to as a species due to increasing drought and to understand the response of the species. In this study, the effects of drought stress on physiological (midday water potential, relative water content, gas exchange parameters) and biochemical (total soluble sugar content) characteristics were investigated in Quercus trojana P.B. Webb. seedlings. Under greenhouse conditions, two treatments were applied to 1+0 old seedlings: control (2-3 times a week for watering) and drought stress (no watering for 30 days). Drought stress was repeated twice, consecutively. At the end of the two-month stress cycle, drought stress decreased the midday water potential, relative water content, net photosynthesis rate, stomatal conductance and transpiration rate, while increasing the water use efficiency and total soluble sugar content. In the study, strong relationships were found between midday water potential, net photosynthesis rate, stomatal conductance, transpiration rate and total soluble sugar content.