ROS regulation during abiotic stress responses in crop plants is crucial for plant survival and productivity. Abiotic stresses such as drought, cold, salt, and heat reduce plant growth and crop yield worldwide. Reactive oxygen species (ROS), including hydrogen peroxide (H₂O₂), superoxide anions (O₂⁻), hydroxyl radicals (OH·), and singlet oxygen (¹O₂), are by-products of cellular metabolism and are tightly regulated by enzymatic and non-enzymatic antioxidant systems. Under stress, ROS levels increase, causing oxidative damage and cell death. However, ROS also play a key role in signaling pathways that help plants respond to stress. ROS are produced in various cellular compartments, including mitochondria, chloroplasts, and peroxisomes, and are also generated at the plasma membrane and apoplast in response to environmental signals. Plants have evolved an efficient antioxidant system, including enzymes like superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT), and glutathione peroxidase (GPX), which help detoxify ROS. Non-enzymatic antioxidants such as glutathione (GSH), ascorbic acid (AsA), carotenoids, and flavonoids also contribute to ROS homeostasis. NADPH oxidases, particularly respiratory burst oxidase homologs (RBOHs), are key enzymes in ROS production and signaling. They are regulated by various factors, including calcium ions, phosphorylation, and signaling pathways involving MAPKs and CDPKs. In crops, RBOHs play a critical role in stress responses, such as drought and pathogen defense. Antioxidant systems in crops are regulated by various transcription factors, including AP2/ERF, WRKY, NAC, and zinc finger proteins, which modulate gene expression to enhance stress tolerance. For example, ZFP36 and ZFP179 are involved in ROS homeostasis and abiotic stress resistance in rice. Additionally, brassinosteroids and abscisic acid (ABA) are important hormones that regulate ROS production and antioxidant defense. The regulation of ROS homeostasis is essential for maintaining plant health under abiotic stress. Strategies such as manipulating ROS levels through genetic engineering or enhancing antioxidant enzyme activity can improve stress tolerance in crops. Understanding the complex network of ROS signaling and antioxidant systems is crucial for developing crops that can withstand environmental challenges.ROS regulation during abiotic stress responses in crop plants is crucial for plant survival and productivity. Abiotic stresses such as drought, cold, salt, and heat reduce plant growth and crop yield worldwide. Reactive oxygen species (ROS), including hydrogen peroxide (H₂O₂), superoxide anions (O₂⁻), hydroxyl radicals (OH·), and singlet oxygen (¹O₂), are by-products of cellular metabolism and are tightly regulated by enzymatic and non-enzymatic antioxidant systems. Under stress, ROS levels increase, causing oxidative damage and cell death. However, ROS also play a key role in signaling pathways that help plants respond to stress. ROS are produced in various cellular compartments, including mitochondria, chloroplasts, and peroxisomes, and are also generated at the plasma membrane and apoplast in response to environmental signals. Plants have evolved an efficient antioxidant system, including enzymes like superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT), and glutathione peroxidase (GPX), which help detoxify ROS. Non-enzymatic antioxidants such as glutathione (GSH), ascorbic acid (AsA), carotenoids, and flavonoids also contribute to ROS homeostasis. NADPH oxidases, particularly respiratory burst oxidase homologs (RBOHs), are key enzymes in ROS production and signaling. They are regulated by various factors, including calcium ions, phosphorylation, and signaling pathways involving MAPKs and CDPKs. In crops, RBOHs play a critical role in stress responses, such as drought and pathogen defense. Antioxidant systems in crops are regulated by various transcription factors, including AP2/ERF, WRKY, NAC, and zinc finger proteins, which modulate gene expression to enhance stress tolerance. For example, ZFP36 and ZFP179 are involved in ROS homeostasis and abiotic stress resistance in rice. Additionally, brassinosteroids and abscisic acid (ABA) are important hormones that regulate ROS production and antioxidant defense. The regulation of ROS homeostasis is essential for maintaining plant health under abiotic stress. Strategies such as manipulating ROS levels through genetic engineering or enhancing antioxidant enzyme activity can improve stress tolerance in crops. Understanding the complex network of ROS signaling and antioxidant systems is crucial for developing crops that can withstand environmental challenges.