Positive Effect of Silver Nanoparticles in In Vitro Flowering and Fruiting of Passion Fruit

One of the effects of silver ions is known to stimulate flowering in plants. With the development of nanotechnology, the application of silver in nano form opens a new way to approach flowering in plants. In the present chapter, the positive effects of silver nanoparticles (AgNPs) were demonstrated on the in vitro flowering and fruiting of purple passion fruit (Passiflora edulis Sims f. edulis). Apical shoots on MS medium supplemented with AgNPs formed flowers and young fruits under in vitro conditions. Adding AgNPs at appropriate concentrations enhanced the bloom rate and diameter of in vitro flowers. Some specific abnormalities of in vitro flowers compared with ex vitro flowers have been noted. Flowers were capable of self-fertilization and fruit formation under in vitro conditions. Furthermore, the treatment with AgNPs significantly improved the fruiting rate, number of fruits, and fruit diameter. On the other hand, a decrease in gibberellic acid, abscisic acid, and melatonin concentrations was observed in shoots grown on medium supplemented with AgNPs. In addition, a significant change in the ethylene content in the culture vessel was also observed on medium supplemented with AgNPs. The combination of AgNPs and spermidine significantly affected the rate of flowering and fruit production as well as the structure of flower buds. The effects of AgNPs described in this chapter open avenues for research of mechanisms and applications to flowering and fruiting in plants.