The Effect of Alginate-Based Silver Nanoparticle Films on Young Arugula Plants (Eruca vesicaria L. subsp. sativa)

Biodegradable alginate films containing silver nanoparticles (AgNPs) are being increasingly investigated as active agricultural materials (e.g., antimicrobial mulches) and active food packaging. However, since these materials ultimately degrade in soil after use, assessing their environmental compatibility and potential phytotoxicity upon release is crucial. The aim of this study was to synthesize films containing AgNPs in sodium alginate using xylose as a reducing agent and to determine their effect on culturable rhizosphere microorganisms and selected biochemical parameters in young arugula (Eruca vesicaria L. subsp. sativa) plants. Alginate films containing three nominal AgNP loadings (50, 100, and 150 mg L^-1) and a control film without AgNPs were synthesized. The films were cut into square pieces (4 cm²) and placed in 0.076 L multipots filled with peat substrate, into which arugula seeds were sown. During the experiment, the abundance of culturable rhizosphere bacteria and fungi was determined, and the young arugula plants were subjected to biochemical analyses. The results showed that the AgNP-containing films did not significantly affect the abundance of bacteria and fungi in the rhizosphere under the conditions tested. The tested films also did not markedly alter the measured parameters in the tissues of young arugula plants, including ascorbic acid, photosynthetic pigments, sugars, dietary protein, and glutathione. However, they reduced phenolic content, altered antioxidant activity, and led to detectable silver accumulation in plant tissues, especially at the highest nominal AgNP loading (150 mg L^-1). These findings indicate limited but selective biochemical effects during the early growth stage of arugula rather than a complete absence of plant response.