Crop productivity depends largely on photosynthetic efficiency, which is key to converting light energy into assimilates for biomass accumulation. The use of biostimulants such as melatonin (MEL) has emerged as a sustainable alternative to imp...

Nanopriming with metal nanoparticles (NPs) is a promising strategy for improving seedling quality in horticultural crops. This study evaluated the effects of hydropriming, ZnO, SiO₂, ZnO + SiO₂, a ZnMo nanofertilizer, and two commercial biostimulants (Osmoplant and Codasil) on the early development of Capsicum annuum L. seedlings. Morphological, physiological, and biochemical traits, including biomass, stem architecture, number of leaves, chlorophylls, carotenoids, SPAD index, and nitrate reductase (NR) activity, were measured under controlled conditions. The ZnO and ZnO + SiO₂ treatments promoted stronger root growth, higher pigment content, and higher NR activity. SiO₂ alone and ZnMo showed intermediate improvements, while Osmoplant and Codasil had more limited effects. Multivariate analyses provided complementary information: heat maps revealed correlations between traits, PCA differentiated treatment responses, and radar charts integrated performance profiles. Overall, the results provide promising evidence that seed nanopriming, particularly with ZnO and ZnO + SiO₂, improves seedling vigor and transplant potential in jalapeño peppers.

The application of nanoparticles (NPs) has become a promising strategy for improving the physiological quality of horticultural seedlings and increasing their tolerance to abiotic stress. In this study, the effects of hydropriming and nanopriming with ZnO, SiO₂, and ZnO+SiO₂, as well as a nanofertilizer containing zinc and molybdenum (ZnMo), and two commercial biostimulants (Osmoplant and Codasil), on the morphological, photosynthetic, and biochemical performance of Capsicum annuum L. seedlings, with the aim of improving both transplant success and stress resistance. Key parameters such as root, stem, and total biomass, stem length and diameter, number of leaves, photosynthetic pigments (chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, SPAD index), and nitrate reductase (NR) activity were measured under controlled conditions. Seedlings treated with NP, particularly ZnO and ZnO+SiO₂, showed superior root development, higher chlorophyll content, and higher NR activity compared to hydropriming, commercial biostimulants, and the untreated control. Multivariate analyses (heat maps, principal component analysis, and radial graphs) revealed synergistic improvements in morphological and physiological traits, with ZnO+SiO₂ emerging as the most effective treatment for promoting a robust and stress-adapted seedling profile. These findings provide strong evidence that nanopriming represents a valuable biotechnological tool for improving seedling vigor and abiotic stress tolerance, contributing to sustainable and efficient horticultural production systems.