Vegetative propagation and the tissues involved in lateral spread of Lythrum salicaria

Abstract

The potential for vegetative propagation of Lythrum salicaria L. (Lythraceae) from stem and root sections, and the tissues involved in the lateral spread of L. salicaria were assessed. Only stem sections consisting of one or more nodes produced shoots and established a new root system. Internodal sections formed adventitious roots and rarely, one occurrence of 36, a new shoot. Neither woody nor non-woody root pieces formed shoot primordia. Entire root systems from which the stem was severed failed to produce new shoots, while root systems in which the stems were severed above the first node formed several new shoots arising from the remaining stem tissue. Plants excavated from field sites revealed that lateral spread of L. salicaria resulted from elongation of lateral meristems on horizontal stems, although the presence of adventitious roots on the stems and changes resulting from secondary growth of both the horizontal stems and adventitious roots gave the appearance of shoot primordia forming on roots. It is concluded that lateral spread and perennation of L. salicaria is facilitated by lateral shoot meristems in the leaf axils and not shoot primordia developing on roots.