SILVER NANOPARTICLES IN THE in vitro ESTABLISHMENT OF GLADIOLUS APICES

Abstract

Plant micropropagation can be limited by various factors, such as in vitro contamination. Disinfection at the establishment stage is one of the most important steps in the prevention of bacterial and fungal contamination. The silver nanoparticles (AgNPs) are a new non-toxic material that shows high capacity in the elimination of microorganisms. The objectives of this research were to evaluate the effect of AgNPs as an auxiliary in the disinfection of gladiolus apices and in the disinfection of the culture medium. The AgNPs were applied as an aid in the disinfection of explants in four concentrations (25, 50, 100 and 200 mg L^-1) and they were combined with four immersion times (5, 10, 15 and 20 min). In addition, the AgNPs were used in five concentrations (0, 25, 50, 100 and 200 mg L^-1), as part of the culture medium to prevent the growth of microorganisms. The amount of 50 mg L^-1 of AgNPs produced the highest percentage of asepsis (91.67 %) and the best shoot length (28.62 mm). The immersion time of 5 to 20 min of the explants in AgNPs had no effect on the asepsis of explants, since the result was similar in the four times of immersion. Factor interaction analysis suggests that 50 mg L^-1 for 15 min was the best treatment. The disinfection of the culture medium with 25, 50, 100 and 200 mg L^-1 of AgNPs generated 100 % asepsis, while the control, without AgNPs, showed 80 % microorganisms contamination. The use of 50 mg L^-1 generated a 35.5 % longer sprout length, compared to the control without AgNPs.