Changes in antioxidative defense systems of Aphanothece halophytica in response to salt stresses
盐度胁迫下盐生隐杆藻抗氧化防御系统的变化

Aphanothece halophytica is a unique halotolerant cyanobacterium, which can grow even in saturated NaCl. In this study, we investigated the effect of salt stress on the levels of malondialdehyde, two non-enzymatic antioxidants and four antioxidant enzymes in A. halophytica. As compared to control salinity condition, an exposure to hyposaline or hypersaline conditions inhibited the growth of A. halophytica. With the increase of salt stresses, malondialdehyde content, levels of non-enzymatic antioxidants, and antioxidant enzymes increased continuously with the exception of catalase. These results suggest that the levels of non-enzymatic antioxidants and antioxidant enzymes in A. halophytica are increased to counteract the enhanced oxidative stress under salt stresses, and the antioxidant defense system may play an important role in the tolerance mechanism of salt stress.