Soil supplementation with silicon nanoparticles to alleviate toxicity signs of salinity in strawberry

The current study investigated the efficiency of soil supplementation with Silicon Oxide (SiO2) nanoparticle product (nSi; 20-30 nm; 0, 0.75, and 1.5 gKg-1) or Potassium silicate (BSi; K2SiO3 as a bulk counterpart) to improve strawberry protection against salinity (NaCl of 2.5 gkg-1). The BSi or nSi utilization not only increased fresh root mass (mean= 23 %) but also mitigated the inhibitory effects of salinity. The salinity, BSi, or nSi treatments made changes in secondary metabolites confirmed by the differential HPLC chromatogram. The soil supplementation with BSi or nSi induced activity of phenylalanine ammonia-lyase. Likewise, the BSi or nSi treatments enhanced concentrations of phenylpropanoid derivatives, including salicylic acid, ascorbic acid, quercetin, apigenin, caffeic acid, catechin, and chlorogenic acid.The individual salinity treatment caused a severe H2O2 accumulation by two folds. However, the BSi or nSi supplementation alleviated the salinity-associated risk of H2O2 accumulation. Salt stress caused a drastic increase in lipid peroxidation levels. However, BSi or nSi applications partially relieved the salinity toxicity on membrane integrity. With a similar trend, the BSi or nSi utilization improved the nutritional status of K+, Na+, and Ca+2 in both leaves and roots. Exposure to BSi, nSi, and/or salinity also enhanced proline concentrations. The BSi or nSi treatments mitigated the salinity-mediated down-regulations in photosynthesis performance. Our findings showed that silicon supplements increased salicylic acid (a signaling compound), ascorbate, and quercetin (two vital antioxidants) as fundamental mechanisms.