Uptake and long-distance transport of carbon in the marine phanerogam Posidonia oceanica

Using the I4C method in situ, we examined the transport of newly-formed photosynthates to different parts of Posidom'a oceanica: leaves, rhizomes, roots, and epiphytes.After incubation with labelled carbon and post-incubation In situ for 6 to 24 h, ca 2 to 30% of the fixed marker was found outside the incubated part.The results suggest a physiological relationship between the different leaf shoots of a given rhizome as well as between leaves and epiphytes.Rhizomes appear to serve as a storage and redistribution organ for photosynthesis products.Redistribution of such photosynthesis products is not haphazard but rather is directed to organs with high metabolic rates such as leaves in rapid growth phase or apical shoots undergoing division.O Inter-ResearchIPrinted in F. R. Germany