Abiotic Stress-induced Changes in Bioactive Compounds of Fruit Crops: A Review

Abstract

Abiotic stress is one of the major constraints limiting crop productivity, plant growth, and fruit quality worldwide. Environmental stresses such as drought, salinity, temperature extremes, heavy metals, and oxidative stress adversely affect plant metabolism, development, and survival. This review synthesizes published literature on the role of plant secondary metabolites in mediating tolerance to major abiotic stresses. Particular emphasis is placed on the functions of terpenes, phenolic compounds, and nitrogen-containing compounds in plant stress adaptation. Nitrogen-containing compounds have greater effects against biotic stress than abiotic stress. The reviewed studies indicate that secondary metabolites play significant roles in mitigating abiotic stress. Phenolic compounds, particularly flavonoids and stilbenes, function as powerful antioxidants and photoprotective agents, while terpenes contribute to cellular stability under stress conditions. Nitrogen-containing metabolites, including alkaloids, glucosinolates, and cyanogenic glycosides, also participate in defence responses and stress tolerance. Collectively, these compounds contribute to Reactive Oxygen Species (ROS) scavenging, antioxidant activity, osmotic regulation, membrane stability, and stress signalling pathways. The findings highlight the diverse mechanisms through which secondary metabolites enhance plant resilience to environmental stresses. Their accumulation and activity are critical components of plant adaptive responses and may influence stress tolerance across different crop species and stress conditions. Secondary metabolites play a crucial role in enhancing plant adaptation to adverse environmental conditions. A better understanding of their mechanisms of action may facilitate the development of stress-resilient crops and support sustainable agricultural production under changing climatic conditions.