Effect of brassinosteroids on rooting of the ornamental deciduous shrubs

Abstract

Brassinosteroids are a developing group of growth regulators. They are a group of steroid hormones involved in plants’ physiological and developmental processes. Among other things, they are responsible for cell wall regeneration or cell elongation. This experiment aimed to examine the effect of rooting stimulants on rhizogenesis in cuttings of two deciduous shrub species: Philadelphus ’Virginal’ and Hydrangea paniculata ’Limelight’. Aqueous solutions of indole-3-butyric acid (IBA) at 200 mg·L–1, Brassinolide (BL) at 0.05% and 24-epibrassinolide (24epiBL) (0.05%) were used in this study. The results obtained showed that both auxin and both of the brassinosteroids used increased the percentage of rooted cuttings almost twice, the degree of rooted cuttings and root length – for BL + IBA – longer roots than the control by 41% in jasmine and by 59% in hydrangea. The growth regulators applied during the rooting of cuttings also caused changes in the organic compound content of plant tissues and the activity of oxidative stress enzymes. The studies and results suggest that brassinosteroids may soon replace the popular rooting stimulants.