Effect of Sodium Deficiency on the Ultrastructure of the Cyanobacterium Anabaena PCC 7119

Avendaño, M. C.; Maeso, E. Sanchez; Nieva, M.; Valiente, Eduardo Fernández

doi:10.1016/s0176-1617(89)80096-3

Cited by 9 publications

(1 citation statement)

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“…Na ¦ deficiency causes impairment in photosynthesis. The defects are due to reductions in chlorophyll content, phycocyanin, photoevolution of O 2 and ribulose bisphosphate carboxylase activity (Apte and Thomas 1983;Rai 1990;Rai andAbraham 1993, 1995), degradation of thylakoids (Avendaño et al 1989) and reduced HCO 3 − transport under low CO 2 tension (Fernández valiente et al 1984;Gonzalez et al 1987). The altered photosynthetic activity could be recovered by addition of combined-N forms (Apte and Thomas 1983), indicating nitrogen starvation as the factor indirectly affecting photosynthesis.…”

Section: Introductionmentioning

confidence: 99%

Response to NaCl of nitrate assimilation and nitrogenase activity of the cyanobacterium Anabaena sp. PCC 7120 and its mutants

Tiwari

1999

J Appl Microbiol

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The presence of NaCl in the nutrient solution promoted nitrate uptake in parent Anabaena sp. PCC 7120, mutants SP7 (defective in nitrate reductase activity) and SP17 (partially defective in nitrate reductase activity), but not in the mutant SP9 (defective in nitrate transport and reduction). Nitrate reductase activity of the parent and mutant SP17 increased with increasing concentration of nitrate in saline medium, while mutants SP7 and SP9 did not respond to the altered salinity. Although Na+ was not required for nitrate reductase activity, its presence in the nutrient solution enhanced nitrate reduction. Complete removal of Na+ from the nutrient solution markedly reduced nitrogenase activity in all the strains, while raising the concentration of NaCl to 50 mmol l−1 or above, was equally toxic to nitrogenase activity. External NaCl at 200 mmol l−1 brought down the nitrogenase activity to the same residual level as observed without Na+.

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