Influence of Hg2+on the growth and the antioxidant system of an Antarctic algae Chlorophyceae L-4 and the feature of its accumulating Hg2+

Abstract:

Antarctic ice algae Chlorophyceae L-4 is an important component and primary productivity of Antarctic ecosystem. It has specific physiological mechanism for longtime survival in the polar environment. When living environment and conditions get change, membrane-lipid system and protein level varies. Ultrastructure of ice algae also changes under heavy metal stress. [Objective] To observe Chlorophyceae L-4 state under Hg2+ stress, and study Hg2+ enrichment and influence on antioxidant system of Chlorophyceae L-4. Then provide theoretical foundation for Antarctic environmental monitoring. [Methods] Drew growth curve of Antarctic algae in different concentration stress conditions of Hg2+and algae ultrastructure observation. Measured MDA content and SOD enzyme activity. Detected Hg2+ enrichment rule by ICP-MS. [Results] Cell count decreased in lower Hg2+ concentration (≤100 μg/L), and in higher concentration (≥250 μg/L), algae cells died. MDA content increases as Hg2+ concentration increased. SOD enzyme activity was enhanced at first and then decreased. Hg2+ enrichment reaches a peak value within one hour and after that, enrichment value reduced slightly. [Conclusion] Hg2+ would be inhibiting and poisonous to the growth of algae. Hg2+ has obvious adverse influence on Chlorophyceae L-4 antioxidant system. Hg2+ absorption of L-4 reach saturation in one hour. Enrichment amount of Hg2+ decreased slightly when it is over concentrated.