Vegetative morphology and meristem dependency the foundation of productivity in seagrasses

Shoot organization in seagrasses varies from the unspecialized condition of Enhalus and Posidonia to the highly differentiated shoot systems of plants like Halophila, Thalassodendron and Thalassia. In the former type proliferation of vegetative meristems seems to be an unordered process, whereas in the latter type proliferation can be very ordered. In some examples, e.g. Syringodium, proliferation of rhizomes is not regularized in shoot organization but is largely a consequence of perturbation by the environment. Since production of new organs and proliferation of indeterminate shoot systems is dependent entirely on continually active meristems, with either a limited tendency to form resting meristems or often no such ability at all, seagrasses show a high degree of meristem dependency.