Selenium aggravates carbon-nitrogen metabolic imbalance by promoting copper uptake and translocation in apple (Malus domestica Borkh.) plants under copper stress.

Selenium increases copper uptake by 72.7% and 41.2% in apple plants under normal and high copper conditions, respectively, by upregulating Cu transport genes.

• Why it matters: Understanding how selenium influences copper absorption is crucial because copper is essential but toxic at high levels, and selenium's role in modulating this balance remains unclear.
• What they did: Hydroponic experiments with apple plants examined the effects of optimal selenium application on physiological traits, Cu uptake, gene expression, and metabolic responses under normal and high copper conditions, involving gene analysis and biochemical assays.
• The result: Selenium enhances Cu absorption and alters gene expression related to detoxification and transport, leading to increased biomass under normal copper levels but causing oxidative stress and growth inhibition under high copper conditions.