Different Responses in Micro-propagation of Three Avocado Cultivars using Silver and Zinc Nanoparticles

In recent years, nanomaterials have drawn considerable interest in different areas of science, including plant tissue culture. A critical step for successful micropropagation is preventing or avoiding microbial contamination. This problem can be described as a bottleneck when using single node culture during the establishment stage of different woody plants. In this study, the influence of (40 and 80 mg/l) of both silver and zinc oxide (Ag and ZnO) nanoparticles (NPs) during establishment and micropropagation stages of avocado "cv." Hass, Fuerte and Red were examined by incorporating AgNPs and ZnONPs into cultural media. Also, in vitro minimal inhibitory concentration (MIC) for both types was studied on various bacterial and fungal strains. The obtained results showed a significant difference between various types and concentrations of nanoparticles on microbial contamination. In relation to how nanoparticles avocado affect tissue culture, the experiments showed that, AgNPs were more effective in increasing all studied parameters compared with ZnONPs. Moreover, adding 40 mg/l of silver nanoparticles to either establishment or multiplication media resulted in the greatest number of shoots/explant, number of leaves/explant and shoot length/explant compared with 80 mg/l. Biometric parameters for shoot multiplication were affected positively by adding 40 mg/l AgNPs to woody plant multiplication medium (WPM). To our knowledge, there are no previous investigations utilizing both types of nanomaterials with avocado cultures in vitro. Our results suggested that, culture media supplemented with AgNPs reflected positively for reducing contamination and the enhancement of avocado micropropagation in vitro.