Mitigation of cadmium toxicity and accumulation in lamb’s lettuce ( Valerianella locusta L.) by silicon: A sustainable approach for food safety

Background: Cadmium (Cd) contamination in food poses serious health risks, especially in leafy vegetables and salads, which are staples in the daily diet. Recently, silicon (Si) has been suggested as a potential solution to limit cadmium accumulation in plants. Methods: This study assessed the role of exogenous silicon application (0.5 mM) on cadmium toxicity, accumulation, and translocation in a commonly consumed salad, lamb’s lettuce ( Valerianella locusta ). Results: Silicon significantly mitigated cadmium-induced toxicity by attenuating its symptoms. Root growth, root and whole plant water content, and the activities of both photosystem I (PSI) and photosystem II (PSII) were improved, particularly PSI through increased oxidation of P700 (P700 ox ). Silicon application also increased proline levels, reduced membrane peroxidation, and restricted cadmium accumulation in shoots, consistent with reduced root-to-shoot translocation. Plants exposed to cadmium (20 μM CdCl 2 ) accumulated 27.8 μg Cd g −1 dry weight (DW) in edible shoots, compared with 2.76 μg g −1 DW with silicon, representing a 90.1% reduction in shoot Cd concentration. Conclusions: These findings indicate that exogenous silicon application can reduce cadmium toxicity and accumulation in the edible tissues of lamb’s lettuce, suggesting a promising approach under the controlled conditions tested. Validation in Cd-contaminated soils under realistic cultivation conditions will help translate these benefits into practical applications.