SILVER NANOPARTICLES AFFECT THE MICROPROPAGATION OF VANILLA (Vanilla planifolia Jacks. ex Andrews)

Abstract

Silver nanoparticles (AgNPs) have various applications in plant biotechnology, mainly to eradicate microbial contamination and promote in vitro development. The aim of this study was to evaluate the effects of silver nanoparticles during micropropagation of vanilla (Vanilla planifolia) in a semi-solid medium. The morphology of nanoparticles was examined with a transmission electron microscope (TEM). For in vitro establishment, nodal segments of 2 cm in length were cultured on Murashige and Skoog (MS) semi-solid medium supplemented with 2 mg L-1 6-benzylaminopurine (BAP). AgNPs concentrations of 0, 25, 50, and 100 mg L-1 and 5, 10, and 20 min exposure times were evaluated during in vitro establishment. For multiplication, shoots of 2 cm in length were transferred to the same medium containing 0, 25, 50, and 100 mg L-1 concentrations of AgNPs. The characterization of AgNPs revealed a spherical shape with a form factor of 0.82, a roundness of 0.88, and average diameters of 35±15 nm. During in vitro establishment, the lowest total percent contamination (23.3, 21.6, and 16.6%) corresponded to explants exposed to 100 mg L-1 of silver nanoparticles for 5, 10, and 20 min, respectively. For shoot multiplication, the greatest lengths, number of shoots, and number of leaves were obtained from 25 mg L-1 and 50 mg L-1 of AgNPs. Treatments with AgNPs had no effect on shoot rooting or plantlet survival during acclimatization. These results suggest that the use of AgNPs can be an effective alternative for the reduction of contamination during in vitro establishment and the promotion of development during micropropagation of V. planifolia.