Grapefruit Extracts and Black Chokeberry Juice as Potential Antioxidant and Antifungal Agents for Carrot Seed Treatment

Grapefruit extracts and black chokeberry juice have antioxidant and antimicrobial properties. The aim of the experiment was to evaluate the effect of grapefruit-based preparations, Biosept Active and Citrogrep, and black chokeberry juice on the germination, vigor, and health of carrot seeds. The seeds of two cultivars were soaked for 30 min in 0.25% grapefruit-based preparations and in 5 and 25% chokeberry juice. Standard ISTA methods were used to evaluate seed germination and health. The chemical composition of the applied preparations and juice was analyzed with ultra-high-performance liquid chromatography electrospray ionization mass spectrometry. The grapefruit-based preparations differed significantly in their chemical composition, qualitatively and quantitatively, but in both of them, flavanones and flavones prevailed. Biosept Active improved seed germination especially in the cultivar, which was characterized by a lower initial seed quality. The significant positive correlations between germination at the first and final counts, as well as the contents of flavanones and flavones, were identified in this cultivar. Moreover, the negative correlations between the percentages of diseased seedlings, dead seeds, the percentages of seed infested with Cladosporium spp., Epicoccum nigrum, Melanospora simplex, and Ulocladium spp., and the investigated compounds were found. Chokeberry juice, at the higher concentration, showed some antioxidant activity; however, it frequently stimulated the growth of the fungi.