Synthesis of indole-3-acetic acid and indole-3-butyric acid loaded zinc oxide nanoparticles: Effects on rhizogenesis

[Display omitted] •Zinc oxide nanoparticles as nanocarriers for plant auxins IAA and IBA.•High loading capacity on zinc oxide nanoparticles.•Increase in rooting efficiency for difficult-to-root Pyrus genotype compared to free auxins.•A promising nanocarrier in agricultural biotechnology. The aim of this work was to investigate the use of zinc oxide nanoparticles (nZnO) as nanocarriers for plant auxins indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA) and determine the effects on rhizogenesis in micro cuttings of different Pyrus species. Auxin loaded nanoparticles (IAA-nZnO and IBA-nZnO) were characterized for particle size, morphology, thermal behavior and chemical structure. A high loading capacity was observed for both auxins (˜90%). Bioactivity assays were performed by using micro cuttings of Pyrus genotypes (Pyrus elaeagrifolia Pall and Pyrus communis L.) under aseptic conditions by dilute solution soaking method. In vitro rooting efficiency was increased at least two folds for the difficult-to-root wild pear (Pyrus elaeagrifolia Pallas) with IAA or IBA loaded ZnO nanoparticles. In this genotype, the highest rooting percentage was achieved for IBA-nZnO and IAA-nZnO at 400 mgL−1 concentration as 50.0% and 41.7%, respectively. Thus, auxin loaded ZnO nanoparticles could be used as efficient nanocarriers in agricultural applications.