谷皮菱形藻的耐盐适应性

ADAPTABILITY OF NITZSCHIA PALEA TO SALINITY

本文报道了在水产养殖上有较大经济价值的硅藻代表种类——谷皮菱形藻对盐度的适应性。该藻有较强的耐盐适应性,在含≤1.0mol/L NaCl的培养基中均能生长,其最适生长盐度约为18‰(含0.25 mol/L NaCl的培养基)。在不同盐度下生长的细胞中其主要生化组分含量有不同程度的改变。类胡萝卜素/叶绿素的比值随盐度的增加略有升高,这主要是由于叶绿素含量随盐度增高而降低所致;细胞蛋白质含量与盐度改变无明显关系;但糖类却随盐度提高而成倍增加,表明糖类是谷皮菱形藻适应盐度改变的主要渗透调节物。同时,在较高盐度时,谷皮菱形藻细胞内氨基酸含量明显增加,显示一些氨基酸特别是脯氨酸在谷皮菱形藻耐盐适应过程中也起着相当的渗透调节作用。

The response of Nitzschia palea to increase in NaGl concentration (0—1.0 mol/L) in the growth media was studied. The alga showed a wide adaptability to salinity. It was able to grow in media containing≤1.0mol/L NaCl, and optimal growth was observed at 0.25mol/L NaCl (S‰=18‰). The contents of main biochemical constituents of cells grown at different NaCl concentrations varied various degrees. A slight increase in the ratio of carotinoid to chlorophyll was observed with increasing salinity due to a decrease in chlorophyll content in the cells. There was no significantly variation in protein content of the cells grown in the media with different levels of NaCl. However, the relationship between the carbohydrate content and the NaCl concentration was found to be linear. Morever, the total amino acid contents of N. palea increased markedly with increases in NaGl concentration from O to 0.75 mol/L in growth media. The results suggested that carbohydrates and free amino acids in the ceils of N. palea were major osmotic regulators during adaptation to externaal salinity changes.