The effect of phloretin on root growth and antioxidant activity in selected plant species in vitro

Abstract

Phloretin is phenolic compound specifically produced in apple tree species and secreted into the soil as a response to biotic and abiotic factors. Since our previous results indicated roots as the primary site of phloretin phytotoxic action, this study focused on assessment of phloretin effects on the root growth of weed (Chenopodium murale and Lotus corniculatus), crop (Solanum tuberosum) and woody species (Castanea sativa and Malus × domestica Borkh.). Significant decrease in root biomass production in liquid growth medium enriched with 500 µM phloretin was observed both after 2 and 4 weeks of treatment in all tested species. The percentages of roots growth inhibition were as follows: Chenopodium murale (95% and 89,1%), Lotus corniculatus (69,4% and 81,8%), Solanum tuberosum (88,4% and 84,7%), Castanea sativa (85,6% and 100%) and Malus × domestica Borkh. (65,3% and 87,4%, respectively). Total antioxidant capacity (TAC), total phenolic content (TPC), as well as antioxidant enzymes activities were determined spectrophotometrically in treated and control Chenopodium murale roots after 4 weeks of phloretin treatment. TAC increased 44,1% presumably due to elevated TPC (25,8%) in treated roots. However, there were no significant differences in catalase (CAT), guaiacol peroxidase (POD) and superoxide dismutase (SOD) activities in control and treated roots after 4 weeks of treatment. Increased antioxidant activity in treated roots is presumably the consequence of known phloretin antioxidant potential.