THE TRANSLOCATION OF 32P IN TWO SUBMERGED AQUATIC ANGIOSPERM SPECIES

Abstract

The translocation of phosphorus as ³²P was investigated in two species of rooted, submerged, aquatic angiosperm, Potamogeton pectinatus and Potamogeton crispus. Experiments were conducted in two forms of partition apparatus for periods of either 1 to 48 h or 6 to 10 days. The apparatus used for the shorter-term experiments incorporated three compartments so that possible isotope leakage through seals could be critically distinguished from plant excretion. Results of autoradiography and of radioactive counting provide evidence for a circulation of ³²P in these plants akin to that described for terrestrial plants but with slower rates of movement. Quantitative differences in rates and amounts of ²P transport in the two species are discussed in relation to their anatomy and ecological distribution. There was no evidence of excretion of isotope, following transport, in the experiments conducted.