New Structural Fragments of Molecules of Chemical Regulators of Plant Growth and Development Stimulating Rhizogenesis

Previous biotesting data on a model of rooting leaf and stem cuttings of beans proposed by the authors as a specific test for auxins allowed a conclusion that the auxin activity is inherent for benzyl alcohols, benzylamines and their quaternary ammonium derivatives. Using a quantitative molecular biotest on a model of three-day-old seedlings of the transgenic Arabidopsis thaliana L. transformed with a construct expressing the β-glucuronidase gene under the control of the auxin-sensitive DR5 semisynthetic promoter it was found that these compounds did not have the auxin activity. We showed that the biotest on the model of rooting of leaf and stem bean cuttings was nonspecific towards auxins and can detect the rhizogenic activity rather than the auxin activity of the compounds under study. Using the biotest on the rhizogenic effect of ten-day-old pea seedlings (Pisum sativum L.) of the Six-Weekly variety we demonstrated that the stress-protectors-phytoregulators under study were comparable by the rhizogenic effect with indole-3-acetic acid (IAA), a natural auxin, although they are not auxins. This is consistent with the previous data on the rhizogenic activity obtained on the models of rooting of leaf and stem cuttings of beans and germination of barley seeds. Thus, we showed that oxybenzyl OBzl and aminobenzyl NHBzl groups were new structural elements that ensured a high rhizogenic activity of the chemical regulators of plant growth.