Aminolevulinic Acid Coated—Silver, Copper, and Silver–Copper Nanoparticles: Synthesis, Characterization, and Application in Seed Nanopriming

Seed priming is a potential tool for improving productivity under different environmental conditions. Aminolevulinic acid (ALA) priming can enhance plant tolerance to abiotic stresses, such as salinity, drought, and extreme temperatures. Nanopriming, priming with nanoparticles, can increase seed germination, growth, and plant development. The goal of this work was to compare the germination, growth, and development of sunflower seeds primed at 25 °C for 24 h with five treatments: water, ALA, silver, copper, and copper-silver nanoparticles (ALANPs) using a two-way analysis of variance. ALANPs were prepared by the photoreduction process (ALA as stabilizing/capping agent) and characterized by UV–Vis, transmission electron microscopy, FTIR, and Zeta potential. The germination percentage, shoot length, root length, seedling vigor index (Vi), and allometric coefficient were obtained on the 3rd, 6th, and 10th days after the priming process. The fluorescence spectra of chlorophyll extract of the whole seedling or directly in the cotyledons were measured. According to the results, seed priming with ALANPs enhanced sunflower seed germination capacity, seed growth, and increased chlorophyll production compared to water and ALA-primed seeds.