Physiological, oxidative, and antioxidative responses of Quercus vulcanica Boiss. and Quercus aucheri Jaub. & Spach. under drought stress conditions
Hakan Özden, Gülriz Bayçu KahyaoğluBackground and Aims: Drought stress is one of the most common global factors of abiotic stress affecting plant growth and productivity world-wide. The present study aims to assess the effects of 1, 2, and 4 weeks of drought stress on the two endemic tree species, Quercus vulcanica and Q. aucheri
Methods: After applying drought stress conditions, the study determines the physiological parameters, markers of oxidative damage, and levels of antioxidant enzymes in the leaves and stems of 6-month-old oak seedlings.
Results: The dry and fresh weights were observed to decrease by at least 11.44%, as well as the chlorophyll levels by at least 14%, in both the Q. vulcanica and Q. aucheri that were subjected to 1, 2, and 4 weeks of drought stress. The carotenoid, proline, and anthocyanin levels also increased in the leaves of both Quercus species; however, the amount of ascorbic acid, reduced glutathione (GSH), and total soluble protein decreased in the leaves and stems of both Quercus species. As oxidative stress markers, the levels of hydrogen peroxide (H2O2) and lipid peroxidation were seen to elevate by at least 1.21 fold under drought stress conditions. This revealed some of the alterations in the activities of antioxidant enzymes in the leaves and stems of both Q. aucheri and Q. vulcanica.
Conclusion: In conclusion, this study revealed increasing drought stress to have a substantial impact on the physiological parameters and oxidative and antioxidant responses in Q. vulcanica and Q. aucheri. This will contribute to understanding how oak species respond to drought stress and their adaptation strategies.