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Several studies have demonstrated that ultraviolet-band-C (UV-C) irradiation can enhance plants’ natural resistance to pathogens and diseases. A suitable dose of UV-C radiation induces the production of metabolites that strengthen plant defenses, an effect known as “hormesis”. Hormesis presents a promising alternative that could supplement and reduce the use of pesticides, which pose risks to the environment and human health. This paper investigates the effects of UV-C radiation emitted by an array of Light-Emitting Diodes (LEDs) in generating a hormetic response in three kiwifruit species, namely <i>A. chinensis</i> var. <i>deliciosa</i> cv. Hayward, <i>A. chinensis</i> var. <i>chinensis</i> cv. Soreli^®, and <i>A. arguta</i> plantlets, grown <i>in vitro</i> and in pots, exposed to the pathogen <i>Pseudomonas syringae</i> pv. <i>actinidiae</i> (Psa) either before or after UV-C irradiation. Analyses of morpho-physiological parameters and spectrophotometric assays were conducted to evaluate changes in chlorophyll a and b content, carotenoids, total phenols, and antioxidant activity in relation to the UV-C irradiation. Results indicate partial protection against Psa infection and increased levels of chlorophylls, carotenoids, polyphenols and antioxidant activity. The optimal UV-C dose was determined to be 2.2 kJ/m² for <i>in vitro</i> shoots and 1.3 kJ/m², for <i>ex vitro</i> plants.