Foliar-applied selenium nanoparticles alleviate cadmium stress through changes in physio-biochemical status and essential oil profile of coriander (Coriandrum sativum L.) leaves.

Since large areas of agricultural soils around the world are contaminated by Cd, a cost-effective and practical method is needed for the safe production of edible plants. The effective role of many nanomaterials to improve plant yield by mitigating environmental pollutions is addressed; however, the impacts of selenium nanoparticles (Se-NPs) have not been well-known yet. The aim of this work was to investigate foliar application of Se-NPs on yield, water content, proline concentration, phenolic content, lipid peroxidation, and essential oil (EO) attributes of coriander (Coriandrum sativum L.) under Cd stress. The plants were exposed to Cd contamination (0, 4, and 8 mg L-1) and foliar application of Se-NPs (0, 20, 40, and 60 mg L-1). The results showed increased Cd accumulation in roots and shoots of coriander plants upon Cd stress; however, Se-NPs alleviated the uptake of Cd. Cd toxicity, particularly 8 mg L-1, decreased shoot and root weight, chlorophyll (Chl), and relative water content (RWC), while Se-NPs improved these attributes. The Cd concentration at 4 mg L-1 and Se-NPs at 40 or 60 mg L-1 increased phenolic and flavonoid contents as well as EO yield. Proline concentration and malondialdehyde (MDA) increased by enhancing Cd stress, but Se-NPs decreased MDA. The GC/MS analysis showed that the main EO constitutes were n-decanal (18.80-29.70%), 2E-dodecanal (14.23-19.87%), 2E-decanal (12.60-19.40%), and n-nonane (7.23-12.87%), representing different amounts under Cd pollution and Se-NPs. To sum up, Se-NPs at 40-60 mg L-1 are effective in alleviating Cd stress.

Foliar-applied silicon nanoparticles mitigate cadmium stress through physio-chemical changes to improve growth, antioxidant capacity, and essential oil profile of summer savory (Satureja hortensis L.).

The use of nanofertilizers is a promising method for enhancing plant productivity and mitigating environmental pollution. The aim of this study was to show the silicon nanoparticles (Si-NPs) effects on growth, water content, phenolic and flavonoid content, and essential oil (EO) profile in aerial parts of summer savory (Satureja hortensis L.) in cadmium (Cd)-contaminated soil. The pot experiment was conducted with Cd concentration (0, 10, and 20 mg Cd kg-1 soil) and foliar application of Si-NPs (0, 0.75, 1.5 and 2.25 mM of SiO2). The results revealed severe Cd stress (20 mg Cd kg-1 soil) significantly decreased root and shoot weight, relative water content (RWC) but increased Cd accumulation in roots and shoots and proline concentration. Moderate Cd level (10 mg Cd kg-1 soil) improved total phenolic content (TPC), total flavonoid content (TFC), and EO content. Under Cd stress, the 1.5 or 2.25 mM Si-NPs were highly effective concentrations to improve the growth and EO yield. The main EO constitutes were carvacrol (43.12-57.6%), γ-terpinene (20.56-25.6%), p-cymene (5.53-11.3%), and thymol (1.65-8.2%) with changes in their concentrations under Cd and Si-NPs. Heat map analysis (HMA) showed fresh weight, dry weight, and EO yield with a higher variation during these treatments had the most significant impact on distinguishing the clusters. The present study recommended 1.5-2.25 mM Si-NPs in improving the physio-biochemical status of summer savory plants to cope with Cd stress.