The effect of salinity and light intensity stress on fresh weight and some biochemical parameters in green algae Scenedesmus obliquus

In this study, the effects of salinity and light intensity stress on the fresh weight, some of pigments, protein and carbohydrates has been studied in green algae Scenedesmus obliquus. For salt stress, BG11 culture was used with 0, 100, 200 and 300mM NaCl concentrations and for light intensity stress a week after subculture, algae were exposed to 114 μmol.m-2 .s -1 light intensity for 0, 2, 4 and 6 days. Samples were harvested 14 days after subculture and fresh weight of Scenedesmus decreased under both stress. The lowest fresh weight was observed in 300 mM NaCl and six days light intensity treatment and controls were the most. Also the amount of carotenoids severely decreased under these stress. The most of β-carotene and lutein were observed in the control samples and the lowest of them in 300 mM of salt concentration and six day treatment of light intensity. The amount of astaxanthin increased under both stress. These results showed that salinity in applied concentration and also light intensity in different levels significantly reduced growth but increased astaxanthin content. In addition, growth reduction and other parameters were indicative low resistant and incompatibility of this species of algae to salinity and light intensity stress.