锶胁迫下亚心形扁藻生理生化的研究

Strontium Stress of Physiological and Biochemical on Platymonas Subcordiformis

目的以亚心形扁藻为材料,在室内条件下研究Sr2+胁迫对其生理生化的影响。方法采用f/2配方灭菌人工海水培养基培养,用分光光度法测定其生长,硫代巴比妥酸(TBA)比色法测定丙二醛(MDA)含量,黄嘌呤氧化酶法测定超氧化物歧化酶(SOD)活性,原子吸收光谱法测定其对Sr2+的富集能力。结果在实验设计的Sr2+浓度下亚心形扁藻均能生长,但Sr2+浓度较高时,生长受到不同程度的抑制,细胞密度分别减少10.1%和21.0%;叶绿素含量随着锶浓度的升高而降低,呈负相关关系;MDA含量随Sr2+浓度的升高而升高,当Sr2+浓度大于5.76mmol/L后急剧降低;SOD活性在Sr2+存在时始终维持一个较高的水平,且随Sr2+浓度的增高而先升高后降低,脂肪酸的种类随Sr2+浓度的升高而减少;亚心形扁藻表现出对Sr2+的高富集能力。结论亚心形扁藻对锶胁迫具有较高的耐受能力和富集能力,有望通过进一步的研究为重金属污染的处理提供更多的资料。

Objective: To investigate the physiological and biochemical effects of strontium on the marine microalga P. subcordiformis. Methods: The microalga was maintained in sterilized artificial seawater enriched with f/2 medium. The growth of microalgae was measured spectrophotometrically at wavelength of 675 nm. The Malondialdehyde(MDA) content was determined by the method of thiobarbituric acid(TBA) and total superoxide dismutase activity(SOD) was determined by the ferric cytochrome c method. Strontium content and the remaining concentration of strontium in the filtrate were analyzed by an atomic absorption spectrophotometer. Results: It showed that the microalga could grow in all the strontium concentrations assayed, but cell numbers decreased 10.1% and 21.0% when Sr2+ concentration was higher than 5.76 mmol/L. Chlorophyll contents decreased when Sr2+ concentration increased. The SOD activity maintained a high level when Sr2+ was added in the culture medium, MDA content increased with Sr2+ concentration raise,but higher than 5.76 mmol/L provoked a decrease. The components of fatty acids decreased when Sr2+ concentration rose. The algal biomass exhibited high uptake capacity for strontium. Conclution: This study showed that Platymonas subcordiformis had a very high strontium tolerant and uptake capacity.