Effect of Adden N-Sources on Salinized Scenedesmus Obliquus

The physiological responses of Scenedesmus to short-term NaCI salinization or to treatments with combinations of NaCI and NaNO3 or NH4CI were investigated. With the rise of NaCI salinization level in the culture medium, the photosynthetic O2-evolution was markedly reduced whereas respiration was generally promoted. The contents of soluble carbohydrates, soluble proteins, free amino acids (in particular proline) were raised with the rise of NaCI level. The addition of NaNO3 especially in small amounts resulted in a promotion of photosynthetic O2-evolution and O2-uptake when compared to those of the reference culture containing only NaCI as a salinizing agent. The contents of soluble proteins, amino acids, including proline also increased when compared to those of control culture, but when compared to those of reference cultures, these contents decreased with the rise of combination level. Addition of NH4CI resulted in a suppression of photosynthetic O2-evolution and respiration and in an elevation of the contents of soluble carbohydrates and soluble proteins and free amino acids.