VEGETATIVE PROPAGATION AND THE TISSUES INVOLVED IN LATERAL SPREAD OF LYTHRUM-SALICARIA

The potential for vegetative propagation of Lythrum salicaria L. (Lyth raceae) from stem and root sections, and the tissues involved in the l ateral spread of L. salicaria were assessed. Only stem sections consis ting of one or more nodes produced shoots and established a new root s ystem. Internodal sections formed adventitious roots and rarely, one o ccurrence of 36, a new shoot. Neither woody nor non-woody root pieces formed shoot primordia. Entire root systems from which the stem was se vered failed to produce new shoots, while root systems in which the st ems were severed above the first node formed several new shoots arisin g from the remaining stem tissue, Plants excavated from field sites re vealed that lateral spread of L. salicaria resulted from elongation of lateral meristems on horizontal stems, although the presence of adven titious roots on the stems and changes resulting: from secondary growt h of both the horizontal stems and adventitious roots gave the appeara nce 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 roo ts. (C) 1997 Elsevier Science B.V.