Defense Date


Document Type


Degree Name

Master of Science



First Advisor

Robert Fisher


Nostoc punctiforme is a nitrogen-fixing, symbiotic/free-living cyanobacterium. There has been a great deal of research conducted on the genomic nature of N. punctiforme as it pertains to its ecologically important role in the nitrogen cycle in varied environments around the world. My study concentrated on the dormant cell type known as the akinete. Increasing concentrations of NaCl were used to follow the growth phases from germination to akinete formation (lag phase-logarithmic growth phase-stationary phase). I found that increased salt concentrations caused N. punctiforme to form akinetes faster when compared to the control. Germination rates were not greatly increased or shortened by salt concentrations at or below 40 mM NaCl. Damage to cells due to NaCl was observed between 105 mM and 500 mM. Physiological studies, such as this one, enable better quantifiable field research since the organism’s limitations under laboratory conditions are known. This research allows researcher to more accurately plan and pick study sites, develop field studies and gives a solid basis for comparison to the natural environment.


© The Author

Is Part Of

VCU University Archives

Is Part Of

VCU Theses and Dissertations

Date of Submission

August 2008

Included in

Biology Commons