MEPS prepress abstract  -  doi: 10.3354/meps07408

ABSTRACT: The existence of apical dominance and the importance of clonal integration to apical growth in the seagrass Syringodium filiforme were examined using field and mesocosm experiments. In the field, apical dominance was observed with proliferative branching resulting from the removal of apical meristems. Rhizome internode length and branching increased when plants grew from a dense meadow into a bare patch, providing further evidence for the existence of apical dominance in S. filiforme. The results of the experiments indicated that growth of the apical meristem is dependent on the translocation of resources from older ramets. Removing 3 shoots from a rhizome runner lead to a significant reduction in the growth of the apical meristem, and removing 6 shoots had a greater effect. Apical growth was more significantly impacted by cutting the rhizome, with the lowest growth observed in clonal fragments comprised of an apical meristem and the 4 youngest ramets. We conclude that clonal integration is an important factor regulating the growth form and productivity of S. filiforme. These results have implications to damage assessment and restoration projects, and indicate that future studies of meadow structure and plant production should consider apical meristem health and branch formation along with individual ramet growth.