Responses of Helichrysum arenarium (L.) Moench Distributing in the Sivas Region to Drought Stress via the Antioxidant Defense System

Helichrysum species are recognized for their therapeutic properties as aromatic herbs that have been utilized for millennia in both conventional and alternative medicine. In the germination and early growth stages of Helichrysum arenarium (L.) Moench (immortelle) seeds obtained from the Sivas region were attempted to ascertain the morphological, physiological, and antioxidant defence system-based responses to drought stress. Immortelle seeds grown in vitro under PEG-6000 (%0-30 PEG) were exposed to drought stress. Germination test results showed that seeds could not germinate in 20% and 30% PEG medium and 15% PEG medium significantly inhibited growth in the early stages of seedling development. The physiological and biochemical responses of plants in PEG-6000 (0% (control), 5% and 10% PEG) medium during the early stages of seedling development were examined over a two-week period. The growth parameters decreased by 5% and 10% PEG medium. In addition to leaf water content (LCW), catalase (CAT) and glutathione reductase (GR) activities; APX, H2O2, SOD and TBARS values also increased. According to the seventh day data, CAT and GR activity decreased, SOD activity did not change. This observation indicates rapid responses in drought-tolerant plants such as H. arenarium, highlighting the necessity for further investigation within a seven-day period.