Interactive effects of elevated CO2 concentration and drought stress on some physio-morphological and biochemical characteristics of Quercus brantii seedlings

Abstract

Abstract The elevated atmospheric CO2 concentration is expected to increase plant growth and productivity and improve water use efficiency. Hence, elevated CO2 is considered to mitigate to some extent the adverse effects of drought. We aimed to investigate physio-morphological and biochemical responses of 2-year-old Persian oak (Quercus brantii Lindl.) seedlings to the elevated CO2 concentration and drought alone and when combined. Persian oak seedlings were grown in growth chambers at two CO2 concentrations (ambient; 380 ppm and elevated; 700 ppm) and two water regimes (well-watered; 100% of field capacity and water stress; about 50% of this value) for one growing season (8 months). The results showed elevated CO2 concentration significantly increased collar diameter, shoot height, leaf area, biomass production, root volume, photosynthetic traits, leaf pigments (chlorophyll and carotenoids) content, and relative leaf water content. While, it decreased total N content of leaves, proline content, electrolyte leakage, Malondialdehyde content, and antioxidant enzymes (catalase, peroxidase, and ascorbate peroxidase) activity in comparison to ambient CO2 concentration. However, the root length was unaffected in response to elevated CO2. In contrast, drought had an adverse effect on the studied traits except for root length. These effects were alleviated by the presence of CO2, as apparent in physio-morphological and biochemical traits. Our findings suggest that in different proposed climate change scenarios, Persian oak trees may tolerate drought in the presence of elevated CO2.