The Effect of Biostimulators and Indole-3-Butyric Acid on Rooting of Stem Cuttings of Two Ground Cover Roses

One of the important groups of roses are ground cover roses, used not only as garden plants but also in urban green areas for covering scarps and hill slopes. Roses are mostly propagated in vitro and by budding, grafting, and cuttings however, the latter is feasible only in certain rose groups. To hasten the production of plant material, preparations that stimulate rhizogenesis are used, which are based mainly on auxins and enhance the growth of adventitious roots in cuttings. Other substances capable of stimulating plant growth are biostimulators, which can be an alternative to rooting formulations containing auxins. The goal of this experiment was to compare the effects of the biostimulators AlgaminoPlant and Goteo with that of the synthetic auxin indole-3-butyric acid (IBA) on rooting of cuttings in two ground cover roses Elfrid ('Kormuse') and Weisse Immensee ('Korweirim'). In the preparations, IBA in the form of Rhizopon (1% IBA) or water solution (200 mg L-1) was used, whereas the biostimulators were applied at the concentration of 0.2% for foliage spraying. Both biostimulators positively affected the percentage of rooted cuttings, whereas their effect on the degree of rooting was comparable or slightly weaker than that of synthetic auxin. Both biopreparations stimulated the growth of new shoots in cuttings. The use of Goteo resulted in increased content of chlorophyll and total soluble sugars in cuttings, whereas levels of free amino acids and polyphenolic acids were decreased. The synthetic auxin IBA increased the total sugar concentration and the free amino acid contents in cuttings were decreased.