A PHYTOCHROME-MEDIATED ALTERATION FROM STEM TO ROSETTE GROWTH ON CHICORY ROOT EXPLANTS IN-VITRO

Chicory root explants (Cichorium intybus L. var. foliosum) of two cult ivars, taken before and after hydroponic forcing, were cultured in vit ro in complete darkness supplemented with red and far-red light treatm ents. Using 5 min red light per day, the strong stem elongation occurr ing in complete darkness was converted to rosette formation. This reac tion was reversed to stem elongation (accompanied by leaf formation) a dding 15 min far-red light after the red light. Fifteen min far-red li ght per day alone caused the same reaction as 5 min red/15 min far-red light. Far-red light followed by red light caused rosette formation. In stems, formed under complete darkness in vitro, the presence of phy tochrome was shown. No phytochrome was detected in the root fragment i tself.