Alleviation of Copper Stress in Tomato Plants using Proline and Melatonin in an Open Soilless System

Summary

This two-season field trial on a commercial soilless farm in Egypt investigated how increasing copper concentration in the nutrient solution (48–192 ppb) affected tomato plant physiology and yield. Elevated copper significantly reduced plant biomass, fruit yield, and nutrient content (N, P, K), whilst accumulating in plant tissues and inducing oxidative stress. Foliar applications of proline or melatonin were tested as potential mitigants to protect plants from copper toxicity, though the abstract excerpt provided does not fully detail the protective efficacy of these treatments.

Regional applicability

This study was conducted in Egypt under soilless production systems in a semi-arid climate. Findings may be partially applicable to protected horticulture in the United Kingdom, particularly for commercial glasshouse tomato production, though UK soilless systems typically operate under stricter water quality and nutrient management protocols that would limit copper accumulation to levels below those tested here. The protective role of proline and melatonin could be evaluated in UK soilless systems if copper contamination or phytotoxicity becomes a practical concern.

Key measures

Fresh and dry weight of roots and aerial parts; fruit number and weight per plant; productivity; leaf nitrogen, phosphorus, potassium, and copper content; chlorophyll, protein, and proline content; hydrogen peroxide, MDA, catalase and superoxide dismutase activity

Outcomes reported

The study measured the effects of elevated copper concentrations (48–192 ppb) in nutrient solution on tomato plant growth, yield, elemental composition, and oxidative stress markers, and evaluated whether foliar applications of proline or melatonin could alleviate copper toxicity symptoms.

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