Allelopathic Influence of Cyanobacteria Microcystis aeruginosa on Green Algae Chlorella vulgaris

Abstract

Organic compounds not directly involved in the normal growth, development and reproduction of organism are called secondary metabolites. The growth and development of biological and agricultural systems could be affected by secondary metabolites with biological activity. This phenomenon is known as allelopathy. Allelochemicals could have influence on different physiological processes of target organism cells, which could lead to growth inhibition or even death. The goal of this work was to investigate allelopathic influence of cyanobacteria Microcystis aeruginosa on green algae Chlorella vulgaris. Both species occur in Baltic Sea; furthermore, M. aeruginosa could locally form toxic blooms (HABs) in coastal zone. Axenic cyanobacterial monocultures were cultivated in the flasks on liquid medium. After 30 days of growth cell-free solutions from cyanobacterial cultures were collected by filtering through the glass-fiber filters in sterile conditions and added to Chlorella vulgaris cultures. The influence of obtained extracellular secretion on growth of green microalgae was investigated after 3 and 7 days. In other experiment the influence of living cyanobacterial cells on growth of green algae was investigated (cocultures). In both experiments M. aeruginosa demonstrated allelopathic effects towards green algae. © Springer International Publishing Switzerland 2014.