CHANGES IN THE LIPID PEROXIDATION INTESITY IN AUXIN TREATED CHERRY ROOTSTOCKS SOFTWOOD CUTTINGS

In order to investigate the effect of phytohormones exogenous auxins on the level of the mechanical injury induced oxidative stress,
intensity of lipid peroxidation (LP) was measured in rootstocks of cherry softwood cuttings. Basal parts of the cuttings and leaves of five rootstocks (Mahaleb 1 and 2, Gisela 5, European ground cherry (EGC) and “Oblačinska” sour cherry) were sampled 0, 2, 4 and 6 days after cutting. Cuttings were treated with 0.5% solutions of three auxins: α-naphthylacetic acid (NAA), indolebutyric acid (IBA) and combination of these two (INCIT K). Results obtained for the LP intensity varied depending on the rootstock, plant organ and auxin applied. The best LP-lowering effect of auxins occurred in all genotypes when treated with NAA. In the leaves, the LP peaked on the 2^nd day while the best LP-lowering effect was recorded in European ground cherry rootstocks on the 4^th day, independently of auxin applied. The highest MDA production in leaves was recorded in Mahaleb 2 and European ground cherry rootstocks treated with IBA (60-90% higher then control) two days after the cuttings were made. It has been established that in the most of the rootstocks examined auxins showed lowering effect on LP which points to their positive effect, not only on rooting of softwood cuttings, but on their antioxidant protection system, as well.