The effect of the biostimulator Goteo on the rooting of ninebark stem cuttings

As a consequence of restrictions on the use of preparations containing synthetic auxins in nursery production, there is a necessity to replace them with more environmentally friendly biopreparations efficiently stimulating plant growth. The aim of the presented experiment was to compare the effects of the synthetic auxin indole-3-butyric acid (IBA) and the biostimulator Goteo on the rooting of ninebark stem cuttings (Physocarpus opulifolius ‘Dart’s Gold’ and ‘Red Baron’) and to get some insight into the latter’s mechanisms of action in plants. Applications of the biostimulator Goteo produced comparable or slightly weaker effects compared to the treatments with IBA. Goteo stimulated elongation in new growth of cuttings when applied in watering or two-fold spraying methods. Application of the biostimulator resulted in increased levels of chlorophyll, soluble sugars and indole derivatives, while the contents of free amino acids and polyphenolic acids decreased. The above results indicate that, if necessary, Goteo may replace the synthetic auxin IBA in the propagation of ninebark in the future.