Phosphatase activities and phosphorous fractions in two periphytic cyanobacteria in response to some pesticides

ABSTRACT

The addition of dursban, dimethoate, karathane and trifluralin at various doses to the nutrient medium of Anabaena oryzae and Nostoc muscorum resulted in significant increase in the total posphorous contents of both organisms as well as in the total soluble, total insoluble, inorganic and organic posphorous fractions. Irrespective of some minor fluctuations, the accumulation of DNA-P and RNA-P was progressively increased. However, the magnitude of this effect differed among the two cyanobacteria. The activities of acid and alkaline phosphatases were accelerated following all pesticide applications, depending on the organism, the pesticide, its dosage and on prevailing conditions. Differences between Nostoc and Anabaena in phosphatase activities could be due to differences in the potential of the organisms to degrade the pesticide, or to differences in competitive and noncompetitive stimulatory and/or inhibitory action of the different pesticides upon acid and alkaline phosphatases