Abstract

The effects of different nutrient sources (nitrogen, phosphorus and carbon) on the growth status and glycogen reserves in Synechocystis sp. strain PCC 6803 and Anabaena sp. strain PCC 7120 were studied. The two cyanobacteria grew well on suitable nutrient sources, for example, nitrate (sodium nitrate), phosphate (two potassium hydrogen phosphate) or inorganic (sodium carbonate, dicarbonate) and organic (sodium acetate, glucose) carbon. On the contrary, the growth rate decreased markedly when grown on ill-suited nutrient sources, for example, ammonium (ammonium chloride), organic nitrogen (urea), pyrophosphate (sodium pyrophosphate) and organophosphate (D-Glucose,6-(dihydrogen phosphate) sodium salt (1:2), adenosine-triphosphate). The yield of phycocyanin and chlorophyll a was higher when grown on suitable than ill-suited nutrient sources, whereas, the activities of superoxide dismutase (SOD) and peroxidase (POD) were higher on ill-suited than suitable nutrient sources, and the glycogen reserves presented the same variation tendences as peroxidase. These results indicate that the nutrient sources used in this study were involved in regulation of (1) the contents of pigments and glycogen, (2) energy and electron transport efficiencies of photosynthesis, and (3) activity level of SOD and POD in Synechocystis sp. PCC 6803 and Anabaena sp. PCC 7120.

Key words: Nitrogen, phosphorus, carbon, growth, glycogen reserves.