Silver and gold nanoparticles impact on in vitro adventitious organogenesis in chrysanthemum, gerbera and Cape Primrose

Abstract

Despite an increasing interest in nanoparticles influence on plant metabolism and growth is recently observed, still it is an under-explored area of research, especially in the context of nanoparticles impact on the in vitro adventitious organogenesis in ornamental plants. The work presents the results of three independent experiments, in which silver and gold nanoparticles, 20 nm-in-size, were poured on the culture medium immediately after explants inoculation. The aim of the Experiment 1 was to evaluate the effect of 10 and 30 ppm silver and gold nanoparticles on the adventitious roots regeneration in Chrysanthemum × grandiflorum (Ramat.) Kitam. ‘Bydgoszczanka’ and Gerbera × jamesonii H. Bol ‘Suri’. Chrysanthemum shoot fragments and gerbera single rosettes were polarly inoculated on the modified MS medium with 2 mg∙L−1 indole-3-acetic acid (IAA) for rooting. Chrysanthemum explants treated with 10 and 30 ppm silver nanoparticles regenerated less adventitious roots than control explants. These roots were also of the smallest area and diameter, but the length of the longest root was the highest in the experiment. Roots parameters after gold nanoparticles treatment were similar to those reported for the control object, expect for one parameter – the biggest values of root diameter (for 10 and 30 ppm). As for gerbera, the efficiency of adventitious roots regeneration was also reduced by 10 and 30 ppm silver nanoparticles, but the addition of 10 ppm gold nanoparticles stimulated rhizogenesis. Similarly to chrysanthemum, the greatest length of the longest root, the smallest root system area and root diameter were also observed under the influence of silver nanoparticles. In the Experiment 2 the effect of 10 and 30 ppm silver and gold nanoparticles on the adventitious shoots regeneration in Streptocarpus × hybridus Voss. was tested. Leaf explants were horizontally inoculated on the modified MS medium with 0.1 mg∙L−1 1-naphthaleneacetic acid (NAA). The best effects in the stimulation of the rosulate and phyllomorphs regeneration were reported for both silver and gold nanoparticles at the concentration of 10 ppm. The aim of the Experiment 3 was to evaluate the effect of 50 and 100 ppm silver nanoparticles on the adventitious shoots regeneration in Chrysanthemum × grandiflorum (Ramat.) Kitam. ‘Lilac Wonder’ and ‘Richmond’. Internodes used as explants were horizontally put onto the modified MS medium with 0.6 mg∙L−1 BAP (benzylaminopurine) and 2 mg∙L−1 IAA. Formation of adventitious shoots was inhibited as a result of silver nanoparticles application at high concentrations.