Modifications phyllotaxique et stélique provoquées par la suppression expérimentale d'un initium foliaire chez le très jeune sporophyte de Phyllitis scolopendrium

Abstract

In the very young sporeling of Phyllitis scolopendrium (L.) Newman, the leaf initium situated at the upper extremity of one of the two helices was microsurgically destroyed. In 5 specimens out of 24 the shoot developed only one foliar helix. This is proven by the contiguous disposition of the successively formed leaves (original phyllotactic diagram) and by the observation of only one focus of morphogenetic activity in the initiating ring, thus supporting the concept of the existence of only one foliar generating centre. When the foliar initium is destroyed, the shoot stelar differentiation is also modified: the vascular system develops a protostele, then a siphonostele. As soon as the first new leaf appears after wounding, the normal solenostele is restored. [Translated by the Journal]