Silver Nanoparticles and Biostimulants Affect Chemical Constituents, Total Phenolics, Antioxidants, and Potential Antimicrobial Activities of <i>Santolina chamaecyparissus</i>

Abstract

The beneficial application of silver nanoparticles and biostimulants to increase crop yield and quality is a long-term strategy to achieve desired agricultural productions that are resilient to various biotic and abiotic challenges. This project aimed to evaluate the individual effects of silver nanoparticles (AgNPs), Ascophyllum nodosum (SEW), and Spirulina platensis (SP) on the growth and physiological responses of Santolina chamaecyparissus. S. chamaecyparissus plants were exposed to AgNPs (20, 40, and 60 mg L−1), SWE (0.5% and 1%), and SP (1%, 2%, and 3%). The finding indicates that the light-harvesting efficiency and plant photochemical capacity are not affected by most treatments except for 60 mg L−1 AgNPs. Furthermore, the pattern of H2O2 levels in leaves was significantly higher after AgNP, SP, and SEW treatments. In parallel, total phenolic production was at least accompanied by a burst in H2O2 levels. However, higher antioxidant activity compared to the control, is shown by the higher free-DPPH-radical inhibition that goes completely smoothly with lower H2O2 levels. Thus, the results of the present study showed that biostimulants overall improved the antioxidant activity of S. chamaecyparissus and induced variable detectable amounts of phenolic compounds in response to the concentrations of each biostimulant.

Keywords

• Antioxidants
• DPPH
• H₂O₂
• phenolics
• RP-HPLC
• AgNPs