The effect of pH on the kinetics of intra- and extracellular uptake of Al in Fontinalis antipyretica: Changes in the cellular contents of K, Mg, and Ca

The effect of acidity on the accumulation of Al in the aquatic bryophyte Fo ntinalis antipyretica was studied. The main interest of this study was in c haracterizing the relationship between the two parameters, as Al is typical ly mobilized in acidic environments, where it becomes extremely toxic. With this aim, a series of laboratory experiments were carried out where sample s of F. antipyretica were held in tanks of water with different concentrati ons of Al (0.1-3 mg L-1) and levels of acidity (pH 3-5.8). The incubation t ime varied between 1 and 24 h. In general, the greatest accumulations of bo th intra- and extracellular Al were found at a pH of 4.4. With the results obtained, the kinetics of both intra- and extracellular Al uptake was chara cterized, and models constructed for different combinations of Al and acidi ty. The study was completed by examining the relationship between the pH of the holding water and bioaccumulation of Al and the variation in concentra tion of cations essential to plant life, which are also indicators of chang es in cellular physiology (K, Mg, Ca). In general, losses of these elements were found at intra- and extracellular locations, especially at high pH.