EFFECT OF LEAD ON THE UPTAKE OF NUTRIENTS BY UNICELLULAR ALGAE

From batch growth experiments carried out with the alga Selenastrum capricornutum Printz the evolution of uptake of nitrogen and phosphorus with time in the absence and presence of lead 1 x 10(-6) M and at pH 7 and 4 has been considered. The change of pigments (chlorophylls a, b and vegetal carotenoids) with time, as well as the labile and total lead in the medium and in the alga and the fluorescence compounds released by the alga, have also been analysed. Relationships between phosphorus in the alga and the pigments and lead in the cell, as well as between phosphorus and fluorescence compounds exudated by each unit of the unicellular alga, have been examined in order to try to understand the biochemical mechanism.