RESUMEN
Nanoparticles (NPs) have the potential to improve plant health and secondary metabolite production. In the present study, three different NPs, i.e., Ag, Cu, and Cu-Ag NPs were produced in the range from 25 to 86 nm, with zeta potentials ranging from -28.8 to -38.5 mV. The synthesized NPs were used for seed priming and foliar spray on three varieties of Capsicum annuum. L, i.e., Arka Sweta (AS), Arka Meghana (AM), and Arka Harita (AH) plants grown under greenhouse conditions. Seed priming at various concentrations of NPs (1, 10, 20 ppm) enhanced the seed germination (96%), seedling vigor index (2494-3112.66), seedling length (6-49%), and biomass (46%) of 45 days old Arka Meghana seedlings. Additionally, all plant tissues accumulated significantly higher amounts of chlorophyll (51-142%), carotenoids (23-94.2%), total phenolic content (73%), and total flavonoid content (57%), compared with the control (p ≤ 0.05). The foliar spray of NPs (20-100 ppm) has a protective effect on the chili plants against thrips infestation (30-76%). The foliar spray enhanced chlorophyll (15-62%), carotenoids (15-50%), total phenolic content (20-62%), total flavonoid content (64-99%), reducing sugars (15-97%), total antioxidant activity (15-142%), ferric reducing antioxidant power assay (15-109%), DPPH (129-54 mg mL-1), and capsaicinoids (capsaicin and dihydrocapsaicin) (82-128%). This study illustrates that Ag, Cu, and Cu-Ag NPs suppress thrips infestation and proliferation with enhanced plant growth and biochemical activity, which is inversely proportional to the NP size. Chemical NPs play a crucial role in the economic significance of chili plants, offering a promising avenue for developing pesticides to effectively combat thrips infestation. This advancement holds great potential in enhancing the overall agronomic productivity of the chili crops.
RESUMEN
The objective of this study was to investigate the physiological and biochemical effects of Chitosan nanoparticles on Capsicum annuum plants. The particle size, polydispersity index, composition, and structure of the synthesized chitosan-based nanoparticles (Chitosan (CS), Chitosan-Silver (CSAg), and Chitosan-Copper (CSCu) NPs) were determined by analyzing the zeta potential, FTIR, TEM, and XRD. The seedlings showed improved physiological and biochemical characteristics when 1, 10, and 20 ppm concentrations of nanoparticles (CS, CSAg, and CSCu) were used for 24-h seed priming. The application of nanoparticles in different concentrations (0, 20, 40, 60, 80, and 100 ppm) on the leaves of Capsicum spp. plants resulted in improved physiological traits and protection against thrips by 70-85 %. Furthermore, it enhanced the content of chlorophyll (20-75 %), carotenoids (20-30 %), total phenolics (20-45 %), total flavonoids (40-125 %), reducing sugars (15-40 %), total antioxidant activity (10-82 %), FRAP (10-100 %), DPPH (76-83 mg mL-1) activity, and total capsaicinoids (125-142 %). Therefore, the use of chitosan-based nanoparticles could be considered an environmentally friendly approach to enhance secondary metabolite production, disease resistance, and growth in Capsicum spp. plants for sustainable production.
