Trolox-Mediated Alleviation of Cadmium Toxicity in Grapevines Through Enhanced Mineral Homeostasis and Metabolic Stability

Abstract Heavy metal contamination poses significant challenges to sustainable viticulture, necessitating innovative approaches to protect grapevine health and productivity. However, comprehensive evaluations of antioxidant-mediated protection against cadmium toxicity in integrated physiological systems remain scarce. We assessed mineral homeostasis, organic acid metabolism, and sugar accumulation in three-year-old Vitis vinifera L. cv. Ökuzgözü berries exposed to graduated cadmium (Cd) concentrations (0–20 ppm) with and without 50 µM Trolox supplementation. Treatment effects were highly significant across all measured parameters ( p < 0.001 ). Notably, Trolox application consistently demonstrated protective efficacy, maintaining nitrogen content at 1.53% compared to 0.65% in untreated cadmium-stressed plants, while preserving essential macronutrient (phosphorus, potassium, calcium, magnesium) and micronutrient (manganese, iron, zinc) accumulation under toxic conditions. In contrast, cadmium exposure alone severely compromised mineral nutrition, organic acid biosynthesis, and carbohydrate metabolism, with total organic acids declining from 15.27 to 4.43 mg L⁻ 1 and reducing sugars dropping substantially across all stress levels. Multivariate analysis revealed that Trolox treatment fundamentally reorganized the metabolic network, enhancing coordination between mineral uptake, organic acid production, and sugar metabolism. Particularly, Trolox-supplemented plants formed distinct clusters with elevated beneficial compounds, including preserved tartaric, malic, citric, and succinic acid levels, alongside maintained glucose and fructose concentrations, indicating efficient stress mitigation capacity. These findings show that targeted antioxidant application plays a crucial role in improving grapevine performance under heavy metal stress. Trolox consistently protected multiple vine systems, including nutrient balance, organic acid metabolism, and carbohydrate stability. Rather than just providing support, antioxidant supplementation proved essential for maintaining vine health and metabolic function. This suggests that carefully designed antioxidant protocols adapted to specific contamination conditions could be an effective strategy for sustaining vineyard productivity and fruit quality in heavy metal-polluted areas.