UV-B辐照培养下南极冰藻的形态和超微结构及主要生化组成的变化

对从南极水样中分离到的L-4单细胞绿藻(Chlorophyceae L-4)，模拟南极的紫外辐射环境．在人工UV-B辐照下培养绿藻L-4．以滤除UV-B培养的绿藻L-4为对照组。用电镜对绿藻L-4试验组和对照组的形态和超微结构进行观察比较。结果表明：试验组细胞内积累大量的淀粉颗粒，是对照组的10～20倍；脂肪颗粒是对照组的3～4倍；试验组的细胞膜和细胞壁之间充满大量的黑色颗粒物质，而对照组很少。此外，试验组的细胞普遍较对照组大，且细胞外粘附着大量的白色黏性物质。对绿藻L-4试验组和对照组的蛋白质、脂肪、糖、无机元素的总含量进行测定，结果表明．试验组的蛋白质含量低于对照组14．16％；脂肪含量高于对照组46．65％；可溶性总糖含量高于对照组66．34％；灰分和其它物质含量分别低于对照组38．83％和33．31％。UV—B辐照下南极冰藻的细胞超微结构和生化组成的变化，部分反映了南极冰藻在长期的进化过程中对南极强辐射环境的适应。本研究将为从南极冰藻中获取抗紫外辐射活性物质提供科学依据。

Changes of the Antarctic alga exposed to UV-B in configuration and ultrastructure as well as main biochemical composition

Single-cell alga L-4 (Chlorophyceae), isolated from the Antarctic water , was cultured under UV-B irradiation similar to the irradiation environment in Antarctica. Compared with the control group in the configuration and ultrastructure, the test group showed the cells with massive accumulation of starch particles, which were 10 to 20 times the quantity of the control group, and the fat particles in the test group cells were 3 to 4 times the quantity of the control group. Also, the cells of the test group were full of black particles between their membrane and cell wall whereas few in the cells of the control group. In addition, the cells in the test group were bigger than those in the control group, and had plenty of white sticky substances around them. We also determined the total content of the protein, fat, polysaccharides, inorganic elements in the cells. The results showed that the contents of the protein, inorganic elements, ash in the test group cells were lower than those in the control group, while the contents of the fat and total polysaccharides were higher. The changes of ultrastructure and biochemical composition in the test group cells scientifically reflected that Antarctic ice alga adapted themselves to the strong irradiation environment during their evolution.