Lignification Associated with Decreased Adventitious Rooting Competence of English Ivy Petioles

Abstract

English ivy ( Hedera helix L.) was used to study the relationship between lignin accumulation and adventitious rooting. Juvenile-phase and three chronological ages of mature-phase petioles were collected from clonal stock plants, analyzed for quantity of vascular lignin, and placed in an in vitro rooting assay. Rooting competence was determined by observing the number of roots formed per petiole. The number of roots per petiole differed significantly between juvenile-phase and mature-phase petioles. Lignin accumulation increased during petiole growth and development with chronologically older mature-phase petioles having the greatest amounts of lignin. There was a negative correlation between lignin accumulation and adventitious rooting competence.