Responses of soluble protein contents and antioxidant enzyme activities in leaves of eight mangrove species seedlings to light intensities

Abstract

The restoration and reconstruction of mangrove wetland ecosystem is one of the key research fields in ecological restoration in the coastal zone of South China. In order to reveal the physiological and ecological strategies to light conditions of mangrove species, the characteristics of leaf soluble protein contents and activities of antioxidant enzymes in seedlings of eight mangrove species (Sonneratia apetala, Kandelia obovata, Bruguiera gymnorhiza, Aegiceras corniculatum, Acanthus ilicifolius, Acrostichum aureum, Heritiera littoralis and Hibiscus tiliaceus) under different light intensity treatments (100%, 45%, 30%, and 10% of natural light intensity) were studied using shading control experiment. The results were as follows: (1) Low light intensities had little effect on the leaf soluble protein contents of Bruguiera gymnorhiza, Acanthus ilicifolius and Acrostichum aureum, whereas the other five species showed a decreasing trend of leaf soluble protein contents with the decline in light intensity. (2) The activities of superoxide dismutase (SOD) and ascorbate peroxidase (APX) in the leaves of Bruguiera gymnorhiza, Acanthus ilicifolius and Acrostichum aureum under 10% of natural light intensity treatment had no significant differences compared with the control, while the other five mangrove species showed a decreasing trend of all the five antioxidant enzyme activities. In conclusion, the results indicate that Bruguiera gymnorhiza, Acanthus ilicifolius and Acrostichum aureum are suitable to be planted under the forest with high canopy density, while Sonneratia apetala, Kandelia obovata, Aegiceras corniculatum, Heritiera littoralis, Hibiscus tiliaceus are suitable to be planted under the forest with lower canopy density or planted as middle and upper layer tree species in mangrove. The results of this study provide theoretical guidance for the optimal allocation of artificial mangrove communities.

Keywords

• mangrove species
• light intensity
• antioxidant enzymes
• soluble protein
• physiological adaptation