不同氮营养盐浓度对斜生栅藻生长及化学组成的影响

Effects of different nitrogen concentrations on growth and chemical composition of a freshwater microalga Scenedesmus obliqnus

研究不同氮质量浓度(0.247、2.47、24.7、123.5、247、370.5、740mg/L)营养盐对斜生栅藻(Scenedesmus obliqnus)生长和化学组成的影响,结果表明,不同初始氮质量浓度对栅藻生长及藻体C、N、P含量有显著影响。栅藻生长率随着初始氮浓度的增加而增加,在氮浓度为247mg/L时达到最高值,之后随着氮浓度的继续增加而下降。因此初始氮浓度247mg/L为栅藻的生长饱和浓度。藻体单位体积N含量(mg/L)随着初始氮浓度的增加而增加,但是随着氮浓度继续增加,各浓度处理间栅藻的N含量差异并不明显。因此,环境中氮浓度持续增加并不会显著增加藻体的N含量。随着氮营养盐浓度的增加,栅藻单位体积P含量(mg/L)呈先增加后降低的趋势;而栅藻单位细胞P含量(mg/cell)则随着初始氮浓度的增加而急剧下降。因此,环境中高氮浓度会抑制藻体P含量生成。

An experiment was carried out to evaluate the effects of different nitrogen concentrations on growth and chemical composition of a freshwater microalga Scenedesmus obliqnus.In this study,the culture solutions were designated with seven nitrogen concentrations,which were 0.247 mg/L,2.47 mg/L,24.7 mg/L,123.5 mg/L,247 mg/L,370.5 mg/L and 740 mg/L,respectively.The results showed that different initial nitrogen concentrations had significant effects on the growth and the nitrogen and phosphorus contents of S.obliqnus(P<0.05).The growth rate of algae increased with the nitrogen concentrations of nutrients increasing,peaking at the 247mg/L of nitrogen concentration and decreasing thereafter.Therefore,the nitrogen concentration of 247 mg/L is the saturation concentration for the growth of S.obliqnus.When the nitrogen concentration was 0.247~24.7 mg/L,the N content of unit algae volume(mg/L)increased with the increase of nitrogen concentration of nutrients,but as the nitrogen concentration continued to increase,the N content of algae had no significant difference.With the increase of nitrogen concentration of nutrients,the P content of unit algae volume(mg/L)increased and then decreased,the P content of cell(mg/cell)declined sharply.Therefore,the high nitrogen concentration in surrounding environment would inhibit the production of algal phosphorus composition.