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ISRN Ecology
Volume 2012 (2012), Article ID 935476, 8 pages
Research Article

Effect of Nitrogen and Periphyton Extract on the Growth of Nostoc sphaericum in Cultures

1Departamento de Ecología y Recursos Naturales, Facultad de Ciencias, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510 México, DF, Mexico
2Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Morelos, Avenida Universidad 1001, 62209 Cuernavaca, MOR, Mexico
3Departamento de Matemáticas, Facultad de Ciencias, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510 México, DF, Mexico
4Subdirección de Epidemiología Hospitalaria y Control de Calidad de la Atención Médica, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Vasco de Quiroga 15, Piso 4, Colonia, Sección XVI, 14000 Mexico, DF, Mexico

Received 9 August 2012; Accepted 1 September 2012

Academic Editors: A. Chappelka, D. Pimentel, and R. Zhu

Copyright © 2012 Itzel Becerra-Absalón et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Nostoc sphaericum shows marked growth differences in two Mexican wetland ecosystems consisting of rain forest and tropical deciduous forest, respectively. The amount of nitrogen and periphyton extract dominated by other Cyanoprokaryota had been identified as the most obvious differences between these two ecosystems. We studied the impact of these variables on the physiology and morphology of N. sphaericum. that is, the chlorophyll-a content of the thalli and the changes in the size of the trichomes as well as the cell division rate. Our results combined with a statistical verification indicate that the cell division rate of N. sphaericum with solid media is neither stimulated by nitrogen nor by accompanying cyanoprokaryotes and therefore is assumed to have no impact on the thalli observed in situ. However, these two variables are affecting the size of both the trichomes and the thalli, thus suggested to cause the observed growth differences between the two wetlands.