Plant physiological and biochemical responses to nickel–cobalt–manganese (NCM) exposure under non-acidified and acidified conditions

This dataset contains raw and processed data obtained from controlled plant bioassays assessing early crop responses to mixed-metal exposure under neutral and acidified conditions. Experiments were conducted using four crop species: maize (Zea mays), wheat (Triticum aestivum), canola (Brassica napus), and Chinese cabbage (Brassica rapa subsp. pekinensis). Two experimental regimes were applied: (i) a non-acidified concentration gradient (0–500 mg·L⁻¹) and (ii) an acidified treatment scenario including an acid control and combined metal–acid treatments (200–1000 mg·L⁻¹). The dataset includes measurements of germination indices, seedling growth traits, tolerance indices, fresh and dry biomass, and photosynthetic pigment contents. Oxidative stress indicators and antioxidant enzyme activities measured under non-acidified conditions are also provided. All measurements were obtained from replicated experiments (n = 3) following standardized physiological and biochemical protocols. The dataset includes raw replicate values and processed summary statistics (mean ± standard error) used for statistical analyses and figure preparation in the associated manuscript.