Superoxide radicals, catalase and superoxide dismutase in maize seedlings during anaerobic treatment.
1993
Dai Q. | Yan B. | Lui X. | Huang S. | Wang Z. | Wang Z.
Maize (Zea mays L.) is generally planted in early spring in China and experiences saturated soil moisture due to frequent rainfall. Superoxide is one of the free radicals produced under stress conditions from deleterious reactions of oxygen in plants. In order to understand the mechanism of flood injury, pre-germinated maize seeds, Huangzhao No. 4 (flood-susceptible cultivar), were planted in Wagner pots and subjected to flooding treatment (2 cm above soil surface) at 4-leaf stage for 7 days to investigate the relationship between the concentration of superoxide and the activities of catalase and superoxide dismutase. Unflooded pots served as control. The content of superoxide radical in the maize leaves increased significantly with flooding. Younger leaves has smaller amounts of superoxide than older ones. Catalase activity in the 2nd leaf decreased significantly after 3 days of flooding. Superoxide dismutase showed a similar trend from the 5th day of flooding. Percent reduction of enzyme activities in younger leaves was significantly smaller than that in older leaves. A negative correlation between the amount of superoxide and the activities of catalase (r raised to the 2nd power=0.89) and superoxide dismutase (r raised to the 2nd power=0.75* ) was established. Under anaerobic treatment the enzymatic defense mechanism of maize seedlings is damaged, resulting in free radical accumulation and consequently, injury by excessive amounts of superoxide.
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