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Physiological adaptability of three mangrove species to salt stress

The three mangrove species were treated with different salinity levels over a three-month period. The response and adaptation of these three mangrove species to salinity were shown to be different. Net photosynthesis rate, stomata conductance and transpiration rate of leaves decreased and soluble sugar content in leaves increased, with salt concentration in all three mangrove species. The malondial dehyde (MDA) content in stems and leaves of Sa and Sc | ACTA ECOLOGICA SINICA Volume 27 Issue 6 June 2007 Online English edition of the Chinese language journal Cite this article as Acta Ecológica Sinica 2007 27 6 2208-2214. Available online at www.sciencedirect.com ScienceDirect RESEARCH PAPER Physiological adaptability of three mangrove species to salt stress Liao Yan Chen Guizhu School of Environmental Science and Engineering Sun Yat-sen University Guangzhou 510275 China Abstract The impact of salinity on three arboreal mangrove plants Sonneratia apetala Sa S. caseolaris Sc and Rhizophora stylosa Rs was studied. The three mangrove species were treated with different salinity levels over a three-month period. The response and adaptation of these three mangrove species to salinity were shown to be different. Net photosynthesis rate stomata conductance and transpiration rate of leaves decreased and soluble sugar content in leaves increased with salt concentration in all three mangrove species. The malondial dehyde MDA content in stems and leaves of Sa and Sc somewhat decreased when the salinity was lower than 10 but rapidly increased with increasing salt concentration. The MDA content in stems and leaves of Rs increased only when salinity was greater than 40. No changes were observed in the MDA content of roots in the three mangrove species. The adaptabilities of Sa and Sc to salt tolerance were limited. The more salt tolerant the mangrove Rs the more likely the free oxygen radicals were eliminated through the increase in activity of superoxide dismutase SOD . Results of this experiment identified salinity levels best suited for the growth and metabolism of the species which provides information necessary for maintaining mangrove forestation along the South China coast. Key Words Sonneratia apetala S. caseolaris Rhizophora stylosa salt stress net photosynthesis rate stomata conductance transpiration rate soluble sugar membrane peroxidation SOD Mangroves a kind of xylophyte form unique communities in tropical and .