Toxic effects induced by salt stress on selected freshwater prokaryotic and eukaryotic microalgal species.
In order to determine the short-term impact induced by salt stress, cultures of Dictyosphaerium chlorelloides and Microcystis aeruginosa were grown in presence of increasing sea-salt concentrations. Growth rate and photosystem II activity in D. chlorelloides, and photosynthetic oxygen production (in both species) were analyzed. A concentration-dependent response was obtained with the presence of sea-salt in culture medium, being M. aeruginosa (EC(50(72)) = 76.6 mM) more sensitive to salt stress than D. chlorelloides (EC(50(72)) = 340.7 mM). However, comparative analysis between growth and Phi(PSII) inhibition in D. chlorelloides shown that there are not significant differences among EC(50(72)) values obtained. An immediate toxic response, induced by increase of sea-salt concentration, has been obtained applying the calculated EC(50(72)) values in both species. These results shown that sea-salt acts as a sensitive and rapid toxic compound in algal cells, and that the sensitivity of M. aeruginosa to salinity stress is much higher than that of D. chlorelloides.
Facultad de Quimicofarmacología, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Mexico.
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Bartolomé
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D'ors
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Sánchez-Fortún
D000704:Analysis of Variance; D000460:Chlorophyta / Q000187:drug effects* / Q000254:growth & development*; D005618:Fresh Water; D046931:Microcystis / Q000187:drug effects*; D010100:Oxygen / Q000378:metabolism; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D012965:Sodium Chloride / Q000633:toxicity*; D013045:Species Specificity
D045332:Photosystem II Protein Complex; D012965:Sodium Chloride; D010100:Oxygen