Lignification and growth inhibition of apple-tree roots induced by phenolic compounds from apple-tree root residues

In pot culture experiment, seedlings of apple-tree cultivar ‘Antonovka’ were grown for one month in soil with 0.5%, 1% and 2.5% addition of root residues of ‘Cortland’, ‘Elstar’ and ‘Šampion’ cultivars. The addition of apple-tree root residues to the soil significantly increased the content of phenolic compounds proportionally to the amount of residues added. It was found that the content of phenolic compounds in the soil showed positive correlation with lignin synthesis in roots of ‘Antonovka’ seedlings, which correlated negatively with the root mass.