Impact of Silver Nanoparticles Mixture with NAA and IBA on Rooting Potential of Psidium guajava L. Stem Cuttings

Guava (Psidium guajava L.) has been considered a hard-to-root species, where the percentage of rooting and survival of the stem cuttings is low. To enhance the rooting potential of guava stem cuttings, the current study was conducted to investigate the influence of NAA and IBA alone or combined with silver nanoparticles on the rooting of guava semi-hardwood cuttings. Silver nanoparticles were synthesized using the chemical reduction method. UV/VIS spectra and TEM micrographs confirmed the synthesis of silver nanoparticles (AgNPs) with an average particle size ranging d from 14.8 to 32.4 nm, and zeta potential confirmed the stability of AgNPs due to the high negative charge of zeta potential. Semi-hardwood cuttings of guava were subjected to six treatments, including the dipping in separate aqueous solutions of IBA, NAA, IBA-AgNPs, NAA-AgNPs, dipping in IBA followed by dipping in AgNPs solution (IBA+AgNPs), and dipping in NAA followed by dipping in AgNPs solution (NAA+AgNPs). Results indicated that the hormone type significantly affected all rooting parameters; higher measurements of rooting percentage, root number, root length, and root weight were recorded with IBA treatment, whereas NAA recorded significantly lower values. Auxin-AgNPs (IBA-AgNPs and NAA-AgNPs) and the double-dipping treatments improved rooting efficiency compared with the auxin treatments alone. Cutting of NAA-AgNPs treatment developed a lower number of long roots, while IBA-AgNPs recorded higher values of all root parameters. The present results demonstrated the stimulatory effect of auxin and AgNPs treatments on the rooting of guava stem cuttings.

Automated summary

The study investigated the effects of auxin and silver nanoparticles on the rooting of guava stem cuttings. Results showed that IBA treatment led to higher rooting percentages, root numbers, lengths, and weights, while NAA treatment resulted in lower values. The combination of auxin and AgNPs treatments improved rooting efficiency compared to auxin treatments alone.