PHYSIOLOGICAL AND BIOCHEMICAL RESPONSES OF NOSTOC LINCKIA TO COMBINEDEFFECTS OF ALUMINUM, FLUORIDE AND ACIDIFICATION

The toxicities of NaF, AlCl3 and AlF3, separately or in combination (A lCl3+NaF), for growth, photosynthesis, electron transport, nitrogen an d phosphorus metabolism and ATPase activity of Nostoc linckia were enh anced in the presence of AlCl3, especially at pH values of 6.0 or 4.5. Al uptake from the medium containing AlCl3 was influenced by the pres ence or absence of phosphate. Both photosystems (PSI and PSII) were hi ghly susceptible to AlF4 followed by AlF3 and AlCl3 in effectiveness. IR spectra revealed the formation and existence of AlF4 at pH 6.0 and 4.5 in the culture medium and in the algal cells. Fluoroaluminate toxi city seems to be due to a replacement of phosphate from the nucleotide binding site of ATPases, thereby arresting the release of ATP and the translocation of ions vital for cyanobacterial growth and metabolism.