Biostimulators are preparations intended to improve plant growth and development, especially under stressful conditions. The aim of the study was to evaluate the effect of two biostimulators: AlgaminoPlant (0.2%) and Route (0.1%) on rooting of Cotinus coggygria Scop. ‘Royal Purple’ and their influence on biochemical changes, respiration efficiency and photosynthetic rate during this process. Cuttings were sprayed with water solution of biostimulators once, twice or three times during the rooting period at week intervals. The effectiveness of biostimulators was compared with the formulations traditionally used in the nursery production, i.e. with a rooting powder Rhizopon AA containing a synthetic auxin IBA (2%) or a water solution of IBA (200 mg·dm^-3) applied on leaves. Triple treatments of microcuttings with AlgaminoPlant and a single one with Route significantly increased a rooting degree relative to the untreated control. The highest photosynthesis rate was observed in cuttings sprayed once with AlgaminoPlant and twice with Route. Respiration efficiency was the highest in cuttings treated once and thrice with AlgaminoPlant. The significant increases in chlorophyll (a + b), total soluble and reducing sugars contents were observed in cuttings treated with both biostimulators in comparison to the control. The results suggest that biostimulators applied on cuttings may cause biochemical and physiological changes which increase the stem ability to regenerate roots therefore their application should be considered in nursery practice.

145-157