Physiological Aspects in Propagation of Ninebark

Recently, a trend can be observed to replace plant protection chemicals in nursery production by products of natural origin. Such products increase plants' resistance to stressful conditions and lower their susceptibility to pathogens. They may also offer an alternative to chemicals stimulating rhizogenesis. The aim of this work was to evaluate the effects of foliar applications of AlgaminoPlant, a biostimulator based on a seaweed extract, relative to auxin-containing preparations, on root growth in stem cuttings of common ninebark (Physocarpus opulifolius). Cuttings were sprayed with water solution of IBA or AlgaminoPlant once, twice or three times during the rooting period at one week intervals and powder IBA was also applied directly to the bases of cuttings. The best rooting was observed after powder IBA application and satisfactory results were observed for AlgaminoPlant and aqueous IBA solution. Treatments with AlgaminoPlant and IBA increased photosynthetic efficiency, chlorophyll contents, total soluble sugars, soluble proteins, indole derivatives and catalase activity while the hydrogen peroxide level and peroxidase activity were reduced. The effects of AlgaminoPlant on rhizogenesis were comparable to synthetic IBA, or only slightly lower. Hence, if needed, synthetic auxin IBA may be replaced by AlgaminoPlant which is considered an environmentally friendly product.