Les bruyères in vitro. IX. Édification du système racinaire adventif chez l’Erica ×darleyensis; mise en évidence d'une rythmicité

Abstract

Cuttings of Erica ×darleyensis were cultured in vitro on a medium containing nitrogen in the nitrate form. Development of foliar shoots from axillary buds and the growth of the root system were studied. Appearance and growth of roots were irregular. Periods of rest alternated with periods of rapid growth. Foliar shoots also emerged in a rhythmic manner. The bursts of root growth began a little before or during the rest period of the foliar shoots and went on during leaf expansion. The maximum growth of roots and shoots took place soon after burst following a rest period. Key words: root system, rhythmic growth, Erica, in vitro.