Melatonin enhances drought tolerance in Dendrobium ovatum: Insights into physiological and genomic adaptations

• Melatonin enhances biomass, root, and pseudobulb growth in D. ovatum . • It balances its rhythms, boosts moscatilin, and adjusts tryptophan pathways. • It stabilizes pigments, mitigates photodegradation, enhances photosynthesis. • It improves stomatal & epidermal growth; water efficiency & osmoprotection. • It reduces chromatin, lowers DNA content without changing ploidy, & boosts mitosis. Melatonin, an evolutionarily conserved indoleamine, is increasingly recognized as a crucial regulator in