TY - EJOU AU - Sandoval-Rangel, Alberto AU - Benavides-Mendoza, Adalberto AU - Betancourt-Galindo, Rebeca AU - Pérez-Velasco, Eneida Adilene AU - Puente-Urbina, Bertha Alicia TI - Dose-Dependent Effects of ZnO Nanoparticles on Growth, Gas Exchange, and Inflorescence Quality in Marigold (Tagetes erecta L.) T2 - Phyton-International Journal of Experimental Botany PY - VL - IS - SN - 1851-5657 AB - In soils and substrates, the bioavailability of Zn2+ is generally low. The use of zinc oxide nanoparticles (ZnO-NPs) has emerged as a promising strategy in agriculture to improve zinc availability and stimulate plant growth. Their physicochemical properties and biocompatibility promote greater micronutrient uptake and the regulation of physiological processes in plants. In this study, the effects of five concentrations of ZnO-NPs (0, 100, 250, 500, and 1000 mg L−1) and two application methods (foliar or drench) on the growth, gas exchange, and flowering quality of marigold were evaluated. ZnO-NPs significantly influenced plant growth; plant height and total dry weight increased by 28.6% and 35.2%, respectively, at a concentration of 100 mg L−1. Similarly, the flower diameter increased by 28.6%. The number of inflorescences increased 1.6-fold at 1000 mg L−1, whereas photosynthesis, stomatal conductance, and transpiration increased at 250 mg L1 (84.4, 242.8, and 168.8%, respectively). Intercellular carbon increased by 79.3% with the application of 100 mg L1, and SPAD units increased by 27.2% with the application of 1000 mg L−1. The application of ZnO-NPs significantly improved plant growth and physiological processes, demonstrating their potential as an efficient strategy to optimize crop productivity and quality. KW - Biostimulants; zinc nanomaterials; photosynthesis DO - 10.32604/phyton.2026.083195