Supported by the National Natural Science Foundation of China (30500068, 30170112) and the Chinese Academy of Sciences (KSCX2-SW-322).
Effects of Salt Stress on Carbohydrate Metabolism in Desert Soil Alga Microcoleus vaginatus Gom.
Article first published online: 2 AUG 2006
Journal of Integrative Plant Biology
Volume 48, Issue 8, pages 914–919, August 2006
How to Cite
Chen, L.-Z., Li, D.-H., Song, L.-R., Hu, C.-X., Wang, G.-H. and Liu, Y.-D. (2006), Effects of Salt Stress on Carbohydrate Metabolism in Desert Soil Alga Microcoleus vaginatus Gom. Journal of Integrative Plant Biology, 48: 914–919. doi: 10.1111/j.1744-7909.2006.00291.x
- Issue published online: 2 AUG 2006
- Article first published online: 2 AUG 2006
- Received 22 Dec. 2005 Accepted 23 Jan. 2006
- carbohydrate metabolism;
- desert cyanobacteria;
- exopolysaccharides (EPS);
- osmotic equilibrium;
- salt stress
The effects of salt stress on carbohydrate metabolism in Microcoleus vaginatus Gom., a cyanobacterium isolated from desert algal crusts, were investigated in the present study. Extracellular total carbohydrates and exopolysaccharides (EPS) in the culture medium produced by M. vaginatus increased significantly during the growth phase and reached a maximum during the stationary phase. The production of extracellular carbohydrates also significantly increased under higher salt concentrations, which was attributed to an increase in low molecular weight carbohydrates. In the presence of NaCl, the production of cellular total carbohydrates decreased and photosynthetic activity was impaired, whereas cellular reducing sugars, water-soluble sugars and sucrose content and sucrose phosphate synthase activity increased, reaching a maximum in the presence of 200 mmol/L NaCl. These parameters were restored to original levels when the algae were transferred to a non-saline medium. Sodium and K+ concentrations of stressed cells decreased significantly and H+-ATPase activity increased after the addition of exogenous sucrose or EPS. The results suggest that EPS and sucrose are synthesized to maintain the cellular osmotic equilibrium between the intra- and extracellular environment, thus protecting algal cells from osmotic damage, which was attributed to the selective exclusion of cellular Na+ and K+ by H+-ATPase.
(Managing editor: Ping He)