Frost sensitiveness of chicory roots (Cichorium intybus L.)

This study was conducted to determine if chicory roots (Cichorium intybus L. var. foliosum) can be stored at temperatures below -1 degrees C. Roots from cultivar Focus, produced in hydroponics on two different artificial substrates, were stored at -1, -2.5, -5 and -7 degrees C. After storage at sub-zero temperatures, roots with highest dry weight percentage showed highest chicon production and highest organogenesis capacity. Moreover, the electrical resistance of those roots never decreased significantly during storage, while roots with a lower dry weight percentage had reduced electrical resistance after storage at -7 degrees C. Decrease in electrical resistance was detected before frost damage became visible. Thus, measuring the electrical resistance of root tissue can be used to predict frost damage. The most distinct frost damage symptoms were 'water soaking' and browning of the vascular bundles. According to these results, it can be concluded that storage temperatures below -1 degrees C, but above -7 degrees C, are not necessarily fatal for chicory roots: roots with relatively high dry weight percentage are best able to withstand low storage temperatures. (C) 2000 Elsevier Science B.V. All rights reserved.