Acta Biologica Hungarica

, Volume 57, Issue 3, pp 355–365 | Cite as

Protection Against Salt Toxicity in Azolla pinnata-Anabaena azollae Symbiotic Association by Using Combined-N Sources

  • A. K. Mishra
  • Satya S. Singh


Protection from salt stress was observed in the terms of yield (fresh and dry weight, chlorophyll and protein) and nitrogenase activity. Azolla pinnata appeared highly sensitive to 40 mM external NaCl stress. Fronds of Azolla unable to grow beyond a concentration of 30 mM NaCl and accordingly death was recorded at 40 mM NaCl on the 6th day of incubation. Yield was inhibited by various levels of NaCl (0, 10, 20 and 30 mM). Addition of combined-N to the growth medium protected the association partially from salt toxicity. Among the N-sources (NO3, NH4+ and urea) tried, urea mitigated the salt-induced toxicity most efficiently. Reduction in nitrogenase activity was observed when intact Azolla was grown in nutrient medium either supplemented with different levels of NaCl or combined nitrogen. Only NO3 (5 mM) protected the enzymatic activity from salt toxicity while other concentrations of ammonium, nitrate and urea slowed down the salt-induced inhibition of enzyme activity in Azolla-Anabaena association. These results suggested that an optimum protection from salt stress could be obtained by using a combination of combined nitrogen sources. The reason for this protection might be due to the availability of combined nitrogen to the association, nitrogen is only available through the biological nitrogen fixation which is the most sensitive to salt stress.


Azolla pinnata combined-N growth nitrogenase salinity 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.



Dr. Satya S. Singh is thankful to CSIR, New Delhi for financial assistance. Thanks are also due to Head, Department of Botany for providing laboratory facilities.


  1. 1.
    Apte, S. K., Thomas, J. (1984) Effect of sodium on nitrogen fixation in Anabaena torulosa and Plectonema boryanum. J. Gen. Microbiol. 130, 1161–1168.Google Scholar
  2. 2.
    Blom-Zandstra, M., Lampe, J. E., M. (1985) The role of nitrate in the osmoregulation of lettuce (Lactuca sativa L.) grown at different light intensities. J. Exp. Bot. 36, 1043–1052.CrossRefGoogle Scholar
  3. 3.
    Blumwald, E., Mehlhorn, R. J., Packer, L. (1983) Ionic osmoregulation during salt adaptation of the cyanobacterium Synechococcus 6311. Plant Phsyiol. 73, 377–380.CrossRefGoogle Scholar
  4. 4.
    Cano, E. A., Bolarin, M. C., Perez-Alfocea, F., Caro, M. (1991) Effect of NaCl priming on increased salt tolerance in tomato. J. Hortic. Sci. 66, 621–628.CrossRefGoogle Scholar
  5. 5.
    Cayuela, E., Perez-Alfocea, F., Caro, M., Bolarin, M. C., (1996) Priming of seeds with NaCl induces physiological changes in tomato plants grown under salt stress. Physiol. Plant 96, 231–236.CrossRefGoogle Scholar
  6. 6.
    Deits, T. L., Howard, J. B., (1990) Effects of salt on Azotobacter vinelandii nitrogenase activities: inhibition of iron chelation and substrate reduction. J. Biol. Chem. 265, 3859–3867.PubMedGoogle Scholar
  7. 7.
    Fernandez Valiente, E., Carmen Avendano, M. (1993) Sodium stimulation of phosphate uptake in the cyanobacteria Anabaena PCC 7119. Plant Cell Physiol. 34, 201–207.Google Scholar
  8. 8.
    Fernandez-Valiente, E., Zamoro, I., Sanchez Maeso, E., Bonilla, I. (1984) Protection of CO2 against sodium deficiency in a mutant of Nostoc muscorum. J. Plant Physiol. 11 6, 473–476.CrossRefGoogle Scholar
  9. 9.
    Fogg, G. E. (1973) Physiology and ecology of marine blue green algae. In: Carr, N. G., Whitton, B. A., (eds) The Biology of Blue Green Algae. California University Press, Berkeley, pp. 368–378.Google Scholar
  10. 10.
    Ito, O., Watanabe, I. (1983) The relationship between combined nitrogen uptakes and nitrogen fixation in Azolla-Anabaena symbiosis. New Phytol. 95, 647–654.CrossRefGoogle Scholar
  11. 11.
    Leidi, E. O., Silberbush, M., Lips, S. H., (1991) Wheat growth as affected by nitrogen type, pH and salinity. I. Biomass production and mineral composition. J. Plant Nutr. 14, 235–246.CrossRefGoogle Scholar
  12. 12.
    Lichtenthaler, H. K. (1987) Chlorophylls and carotenoides: pigments of photosynthetic biomembrane. Methods Enzymol. 148, 350–382.CrossRefGoogle Scholar
  13. 13.
    Lowry, O. H., Rosenbrough, N. J., Farr, A. L., Randall, R. J., (1951) Protein measurement with the folin-phenol reagent. J. Biol. Chem. 193, 265–275.Google Scholar
  14. 14.
    Moore, A. W. (1969) Azolla: Biology and agronomic significance. Bot. Rev. 35, 17–34.CrossRefGoogle Scholar
  15. 15.
    Moore, D. J., Reed, R. H., Stewart, W. D., P. (1985) Responses of cyanobacteria to low level osmotic stress: Implications for the use of buffers. J. Gen. Microbiol. 131, 1267–1272.Google Scholar
  16. 16.
    Munns, R., Husain, S., Rivelli, A. R., James, R. A., Condon, A. G., Lindsay, M. P., Lagudah, E. S., Schachtman, D. P., Hare, R. A., (2002) Avenues for increasing salt tolerance of crops, and the role of physiologically based selection traits. Plant and Soil 247, 93–105.CrossRefGoogle Scholar
  17. 17.
    Nayak, S., Prasanna, R., Pabby, A., Dominic, T. K., Singh, P. K., (2004) Effect of urea, blue green algae and Azolla on nitrogen fixation and chlorophyll accumulation in soil under rice. Biol. Fertil. Soil. 40, 67–72.CrossRefGoogle Scholar
  18. 18.
    Niven, G. W., Kerby, N. W., Rowell, P., Reed, R. H., Stewart, W. D., P. (1987) The effects of salt on nitrogen fixation and ammonium assimilation in Anabaena variabilis. Br. Phycol. J. 22, 411–416.CrossRefGoogle Scholar
  19. 19.
    Okoronkwa, N., Hove, C. (1987) Dynamics of Azolla-Anabaena nitogenase activity in the presence and absence of combined-N. Microbios 49, 39–45.Google Scholar
  20. 20.
    Pabby, A., Prasanna, R., Singh, P. K., (2003) Azolla-Anabaena symbiosis — from traditional agricultural to biotechnology. Ind. J. Biotechnol. 2, 26–37.Google Scholar
  21. 21.
    Parida, A. K., Das, A. B., (2005) Salt tolerance and salinity effects on plants: a review. Ecotoxic. Environ. Safety 60, 324–349.CrossRefGoogle Scholar
  22. 22.
    Peters, G. A. (1975) The Azolla-Anabaena azollae relationship III studies of metabolic capabilities and a further characterization of the symbiont. Arch. Microbiol. 103, 113–122.CrossRefGoogle Scholar
  23. 23.
    Peters, G. A., Ito, O., Tyagi, V. V., S., Kaplan, D. (1981) Physiological studies on N2- fixing Azolla. In: Lyons, J. M., Valentine, R. C., Phillips, D. A., Rains, D. W., Huffaker, R. C., (eds) Genetic Engineering of Symbiotic Nitrogen Fixation and Conservation of Fixed Nitrogen. Plenum Press, New York, pp. 343–362.CrossRefGoogle Scholar
  24. 24.
    Peters, G. A., Mayne, B. C., (1974) The Azolla, Anabaena azollae relationship. 1. Initial characterization of the association. Plant Physiol. 53, 813–819.CrossRefGoogle Scholar
  25. 25.
    Planzinski, J. (1990) The Azolla-Anabaena symbiosis. In: Gresshoff, P. M. (ed.) Molecular Biology of Symbiotic Nitrogen Fixation. CRC Press Inc., Boca Raton, Florida, USA, pp. 51–79.Google Scholar
  26. 26.
    Rai, A. K. (1990) Biochemical characteristics of photosynthetic response to various external salinities in halotolerant and fresh water cyanobacteria. FEMS Microbiol. Lett. 69, 177–180.CrossRefGoogle Scholar
  27. 27.
    Rai, A. K., Rai, V. (2003) Effect of NaCl on growth, nitrate uptake and reduction and nitrogenase activity of Azolla pinnata-Anabaena azollae. Plant Sci. 164, 61–69.CrossRefGoogle Scholar
  28. 28.
    Rai, A. K., Abraham, G. (1995) Relationship of combined nitrogen sources to salt tolerance in fresh water cyanobacterium Anabaena doliolum. J. Appl. Bacteriol. 78, 501–506.CrossRefGoogle Scholar
  29. 29.
    Reddy, B. R., Apte, S. K., Thomas, J. (1989) Enhancement of cyanobacterial salt tolerance by combined nitrogen. Plant Physiol. 89, 204–210.CrossRefGoogle Scholar
  30. 30.
    Rodríguez, R., Guerrero, M. G., Lara, C. (1994) Mechanism of sodium/nitrate symport in Anacystis nidulans R2. Biochim. Biophys. Acta 1187, 250–254.CrossRefGoogle Scholar
  31. 31.
    Rodríguez, R., Lara, C., Guerrero, M. G., (1992) Nitrate transport in the cyanobacterium Anacystis nidulans R2. Kinetic and energetic aspects. Biochem. J. 259, 545–548.Google Scholar
  32. 32.
    Seeman, J. R., Critchley, C. (1985) Effect of salt stress on the growth, ion content, stomatal behaviour and photosynthetic capacity of a salt-sensitive species, Phaseolus vulgaris L. Planta 164, 151–162.CrossRefGoogle Scholar
  33. 33.
    Singh, R. P., Singh, P. K., (1989) Effect of nitrogen fertilizers on nitrogen fixation and heterocyst frequency of cyanobacterium Anabaena azollae in seven species of Azolla. Biochem. Physiol. Pflanzen 185, 429–433.CrossRefGoogle Scholar
  34. 34.
    Singh, S. S., Singh, S. K., Mishra, A. K., (2006) Regulation of Na+ influx, intracellular Na+ and Na+ efflux by combined-N sources in Azolla pinnata-Anabaena azollae symbiotic association (communicated).Google Scholar
  35. 35.
    Stewart, W. D. P., Fitzgerald, G. P., Burris, R. H., (1968) Acetylene reduction by nitrogen-fixing blue-green algae. Arch. Microbiol. 62, 336–348.Google Scholar
  36. 36.
    Thomas, J., Apte, S. K., (1984) Sodium requirement and metabolism in nitrogen fixing cyanobacteria. J. Biosci. 6, 771–794.CrossRefGoogle Scholar
  37. 37.
    Tel-Or, E., Melhamed-Harel, H. (1981) Adaptation to salt of the photosynthetic apparatus in cyanobacteria. In: Akoyunoglou, G. (ed.) Photosynthesis. International Science Services, Philadelphia, 6, pp. 455–462.Google Scholar
  38. 38.
    Whitton, B. A. (2000) Soil and rice fields. In: Whitton, B. A., Potts, M. (eds). The Ecology of Cyanobacteria. Kluwer, Dordecht, pp. 233–255.Google Scholar
  39. 39.
    Yost, H. J., Lindquist, S. (1988) Translation of unspliced transcripts after heat shock. Sci. 242, 1544–1548.CrossRefGoogle Scholar
  40. 40.
    Zimmermann, W. J. (1985) Biomass and pigment production in three isolates of Azolla 1. Response to water stress. Annals. Bot. 56, 689–699.CrossRefGoogle Scholar

Copyright information

© Akadémiai Kiadó, Budapest 2006

This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (, which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Authors and Affiliations

  • A. K. Mishra
    • 1
  • Satya S. Singh
    • 1
  1. 1.Department of BotanyBanaras Hindu UniversityVaranasiIndia

Personalised recommendations