Silver nanoparticles in the in vitro aseptic establishment of poinsettia (Euphorbia pulcherrima Willd. ex Klotzsch) var. Belén

Poinsettia (Euphorbia pulcherrima Willd. ex Klotzsch) is the worldwide symbol of Christmas, and its demand constantly grows. The main challenge in the poinsettia in vitro propagation protocol is maintaining aseptic conditions in the culture, as the latex present in poinsettia stems significantly contributes to carbohydrates and other molecules that promote the development of endogenous phytopathogens in the culture medium after establishment. Therefore, the primary objective of this work is to assess the efficacy in achieving an aseptic in vitro culture by the addition of AgNPs at six concentrations (0, 100, 200, 300, 400, 500, and 600 mg/L) to the MS culture medium. Entirely aseptic nodal segments were obtained with the addition of 300 to 600 mg/L of AgNPs. The best shoot induction and growth promotion was obtained with the addition of 400 mg/L to the medium, without compromising explant viability. It is essential to note that shoot induction and growth promotion were achieved without the addition of 6-benzylaminopurine (BA) or naphthalene acetic acid (NAA), which have previously been reported as the optimal conditions for poinsettia micropropagation. These results highlight the potential of AgNPs to accomplish both tasks in the in vitro establishment of poinsettia cultures: eliminating bacterial and fungal contamination and promoting conditions for shoot induction and growth. Silver nanoparticles ensure aseptic conditions in the culture, stimulate growth, and preserve all specimens of Euphorbia pulcherrima Willd. ex Klotzsch var. Belén alive without the addition of cytokinin or auxins.