IS THE APICAL GROWTH OF CYMODOCEA-NODOSA DEPENDENT ON CLONAL INTEGRATION

The importance of clonal integration for the production of biomass by the apical meristem of Cymodocea nodosa (Ucria) Ascherson was tested i n situ by experimental manipulation. The production of new biomass by the apical meristem of a horizontal rhizome, as well as the leaf growt h of the remaining shoots, was greatly reduced when the horizontal rhi zome was severed, even when up to 11 shoots were left connected to the apical meristem of the rhizome. In contrast, the elimination of up to 8 shoots after the 3 apical shoots on a horizontal rhizome did not af fect the production of biomass by the apical meristem. These results s how that growth at the apical meristem of a C, nodosa rhizome depends on resources translocated along the rhizome from shoots situated furth er than 50 cm from the rhizome apex and that all the individual shoots (ramets) in a C. nodosa clone should be considered as one unit. Clona l integration does not depend on the presence of living shoots along t he translocation route but is dependent on the integrity of the horizo ntal rhizome.