Kaya, Armağan2026-01-242026-01-24202597804433385199780443338526https://doi.org/10.1016/B978-0-443-33851-9.00010-5https://hdl.handle.net/20.500.12868/4674In agricultural areas, abiotic stresses affect various plants, including horticultural plants and prompt the reactive oxygen specie (ROS) generation. Excess ROS damages important biomolecules like proteins, carbohydrates, proteins or nucleic acids, causing oxidative damage. Therefore, it is essential for plants to handle adverse conditions for their survival. Melatonin is a biomolecule naturally synthesized in plants and many other organisms, and it improves plant stress resistance by scavenging ROS and stimulating plant defense responses. In addition, exogenous melatonin promotes plant defense responses by upregulating the antioxidant mechanism in plants suffering from abiotic stress situations. However, there is a need to further investigate the relation between melatonin and the stress defense mechanisms of horticultural plants at molecular and biochemical levels, considering the lack of studies on this subject in literature. © 2026 Elsevier Inc. All rights reserved.eninfo:eu-repo/semantics/closedAccessAbiotic stressAntioxidant systemHorticultural plantsMelatoninOxidative stressBook Chapter10.1016/B978-0-443-33851-9.00010-51051302-s2.0-105023921960N/A