Abstract: The change characteristics of physio-biochemical indexes of four mangrove plants Rhizophora stylosa, Kandelia obovata, Bruguiera gymnorhiza and Ceriops tagal seedlings after 28 days of heavy metal aqueous solution stress at different concentrations were studied, including soluble protein content, superoxide dismutase (SOD), and Peroxidase (POD) activity and oxidative damage marker malondialdehyde (MDA) content. The results of the study showed that the SOD and POD activities in the leaves of the four plants all increased first and then decreased. When the Rhizophora stylosa were treated with 10 times the heavy metal aqueous solution, the Kandelia obovata and Bruguiera gymnorhiza were treated with 5 times the heavy metal aqueous solution, the Ceriops tagal were treated with 1 time the heavy metal aqueous solution, it has good antioxidant enzyme activity during heavy metal aqueous solution treatment, which can actively remove active oxygen and reduce oxidative damage. Under the same concentration of heavy metal aqueous solution treatment, the results of MDA content showed that the damage of the Rhizophora stylosa was the least, the Kandelia obovata and the Bruguiera gymnorhiza were basically equally damaged, and the Ceriops tagal were the heaviest. The ability of Rhizophora stylosa to resist heavy metal stress is stronger than Kandelia obovate and Bruguiera gymnorhiza, while the ability of Ceriops tagal to resist heavy metal is the weakest. These results show that mangrove plants have strong ability for anti-pollution, which has important guiding significance for mangrove ecological restoration and protection in China.

Key words: Heavy metal stress, mangrove plants, physiological response, characteristics