EFECTO DE LA SALINIDAD EN LA LIBERACIÓN FOLIAR DE FOSFATO POR LA FANERÓGAMA ACUÁTICA ZOSTERA NOLTII HORNEM. DE LAS MARISMAS DEL RÍO PALMONES (CÁDIZ).

Resumen

We study the et'fects of salinity on the uptake of phospate by roots and rhizomes in the aquatic angiosperm Zostera noltii Hornem., and its possible release through the leaves to the surrounding water. The uptake of phosphate by roots and rhizomes was not affected by different salinity values (36% and 18%0)in the water surrounding the leaves; on the contrary, the foliar release was affeeted. The 6.25% of the phosphate uptaken belowground ogans was released by leaves in the control experiment (36%") cluring a 3 hour incubations, against the 57.87% in the low salinity experiment. Therefore the foliar release of phosphate is low at normal salinities found in the Palmones estuary (34-36%0),but when salinity values decrease (very rarely in this environment), the foliar release become enhanced 10 times, indicating that under these conditions, individual plants could act as a 'phosphate pump'. Nevertheless the atnount of phosphate releascd to the estuary is low due to the low eoverage of this plants.