biologia plantarum

Biologia plantarum 35:481-489, 1993 | DOI: 10.1007/BF02928019

Peroxidases during the course of callusing and organ differentiation from root explants ofCichorium intybus

A. Bouazza¹, S. Rambour¹, T. Gaspar², B. Legrand¹

¹ Laboratoire de Physiologie et Genitique Moléculaire Végétales, Université des Sciences et Technologies de Lille, Villeneuve D'Ascq Cedex, France

² Hormonologie Fondamentale et Appliquée, Institut de Botanique B22, Liège, Belgium

Growth ofCichorium intybus root explants was accompanied by an important increase of fresh mass during the course of callusing and rooting. The absence of glucose in callus forming medium was compensated for by hydrolysis of storage carbohydrates of the tissues, inducing a decrease in dry mass. Protein content showed similar slight variations in explants during the course of budding and callusing, whereas an important increase of protein content was found during the first 48 h in explants cultured on root forming medium.
Specific increase of soluble peroxidase activity during bud and root neoformation was found. A peak of peroxidase activity, proceeding the organ emergence, was always observed. This peak occurred earlier in bud forming than in root forming explants. Conversely, during callusing, the bulk peroxidase activity showed only weak variations, and no peak was detectable. Moreover one basic isoperoxidase was missing in these explants after a 6-d culture, whereas in both root and bud forming explants the isoperoxidase patterns were very similar. When explants growing on differentiation media were in darkness a supplementary basic isoperoxidase with the highest electrophoretic mobility was revealed.
The data obtained show that isoperoxidase patterns cannot be correlated to a particular organ differentiation process, but that peroxidase activity and especially the moment of peak emergence can be a reliable marker of the differentiation process. Moreover, light seems to inhibit the expression of a basic peroxidase in explants growing in media promoting organ differentiation.

Received: June 29, 1992; Accepted: December 3, 1992; Published: December 1, 1993  Show citation