Light-dependent uptake, translocation and foliar release of phosphorus by the intertidal seagrass Zostera noltii Hornem

摘要

Light-dependent P uptake by root-rhizomes, acropetal translocation and subsequent foliar release by Zostera noltii Hornem. was studied under laboratory conditions in two-compartment chambers using 32P. The uptake by underground parts was unaffected by light conditions but the acropetal translocation proceeded more rapidly in light than in dark, indicating a coupling to the metabolic activity of the plants. The translocated P was mainly accumulated in the youngest leaves (30%), i.e., the most actively growing parts. Foliar release of P might be considered negligible (2–4% of the P taken up by root-rhizomes), indicating that the role of Z. noltii as a “P pump” is of minor importance in the cycling of P between sediment and water. This was calculated for part of the Oosterschelde estuary, Zeeland, The Netherlands.