Foliar- and root-applied silicon-based biostimulant increases the nutritional efficiency, fruit firmness and storage potential of nectarines

Silicon is involved in many physiological processes of plants, such as plant water relations, photosynthesis, and mineral uptake and mobility inside plants. Furthermore, silicon can increase chlorophyll content and maintain the stability of cell membranes, which is beneficial to fruits under storage condition. Fresh peaches and nectarines are prone to rapid deterioration after harvest and, consequently, a short postharvest life. After harvest, fruits lose fluid causing a firmness loss and dehydration, which negatively affect their quality. The aim of this work was to study the effect of applications of exogenous silicon in nectarine trees (‘Nectatinto’) on the mineral concentrations, fruit quality and changes of fresh nectarines during cold storage. Codasil^® is a fertilizer composed of silicon (20% SiO₂) and free amino acids (4% w/v). Preharvest foliar applications of Codasil^® at 2 or 3 L ha^‑1, and preharvest root applications at 3 or 6 L ha^‑1, were assessed and compared to an untreated control. Treatments were applied four times between 90 and 30 days before harvest. The foliar applications had a positive effect in the mineral content of fruits (Si, K, Mg, Ca) and increased the dry matter content. Besides, these treatments showed fruits with higher firmness value independently of dose. Root applications at high dose had a positive effect on fruit size, increased Fe content in the exocarp of fruits. In addition, foliar and root applications significantly decreased postharvest dehydration symptoms. These results suggest that silicon applications contributed to mineral uptake and mobility inside fruit and cell walls, involving membrane stabilizing and fortification. Our findings showed that silicon applications improved nectarines tolerance to postharvest deterioration, which closely correlated with the increase in membrane stability. Hence, silicon applications represent a sustainable tool to improve quality and storage of nectarines.