Ultrastructural study of the brown core of Witloof chicory chicon

Abstract

A study of the ultrastructure of the chicon axis suffering from “brown core” has revealed a gradual cell wall weakening. It began in the middle lamella and led to cells collapsing. Breaks of the plasmalemma and of the tonoplast were also noted. The severe deterioration of the cell compartmentation finally led to the formation of dark precipitates in the central vacuole. These observations are consistent with the assumption that the brown core results from a Ca-deficiency.