Effects of copper on growth, accumulation, antioxidant activity and malondialdehyde content in young seedlings of the mangrove species Kandelia candel (L.)

Abstract

The effects of different concentrations of copper (Cu) on the growth, Cu accumulation, antioxidant enzyme activity and malondialdehyde (MDA) content of seedlings of the mangrove species Kandelia candel L. were investigated. Seedlings were treated with several concentrations of CuCl₂ (0, 1, 5, 10, 20, 30 or 40 mg L⁻¹) for 3 months. The results indicated that a high dose of Cu significantly decreased the growth of K. candel in terms of seedling height, leaf number and total biomass. At the highest Cu concentration (40 mg L⁻¹), there was a 39.53% decrease in final seedling height, a 53.25% decrease in leaf number and a 35.96% decrease in total biomass. Cu ions were accumulated mainly in the roots (96%), and only small amounts were translocated to the hypocotyl, leaves and stem. The MDA content increased with increasing external Cu concentration both in roots and leaves. A significantly higher superoxide dismutase, peroxidase and catalase antioxidative enzyme activity occurred in roots and leaves of plants exposed to 20 mg L⁻¹ CuCl₂ compared to other treatments, suggesting that K. candel seedlings can tolerate up to 20 mg L⁻¹ Cu treatment.

Keywords:

• Accumulation
• antioxidant enzymes
• copper
• growth
• Kandelia candel (L.)
• malondialdehyde

Acknowledgements

We thank the two anonymous reviewers for their comments and recommendations that have significantly contributed to improving the manuscript. We also extend our thanks to Mr. Jason Douglas Todd, The University of North Carolina, USA, for his suggestions on organising the manuscript and his painstaking proofreading.