<![CDATA[Background: This study investigated the effects of varying drought stress durations on the growth and accumulation of antioxidant compounds in basil (Ocimum basilicum L.), a plant sensitive to water availability and threatened by prolonged drought due to climate change. Methods: Four treatment groups were established: control (C0: watered daily), C1 (watered every 3 days), C2 (watered every 6 days), and C3 (watered every 9 days). Morphological parameters (root fresh/dry weight, leaf area) and physiological parameters (Relative Water Content/RWC, root-shoot ratio) were measured, along with biochemical parameters (total phenolic content/TPC and total flavonoid content/TFC). Results: Analysis showed that increasing drought duration significantly reduced root fresh weight (C0: 21 g to C3: 3 g), leaf area (C0: 13.2 cm2 to C3: 7.46 cm2), and RWC, which dropped drastically from 71.70 % in C0 to 30.50 % in C3. However, a mild stress level (C1) significantly induced the highest TPC (97.61 ± 2.94 mg GAE/g extract) and TFC (115,97 ± 3.23 mg QE/g extract), surpassing the control (C0: TPC 76.98 ± 3.55 mg GAE/g extract, TFC 85.42 ± 5.08 mg QE/g extract). The concentrations of these compounds then decreased significantly at severe stress levels (C2 and C3), indicating metabolic breakdown. Conclusion: Mild drought stress (C1) is optimal for inducing secondary metabolite accumulation in basil as an adaptive response, while severe stress significantly inhibits growth and reduces physiological capacity.]]>
