The Dependence of Cell Division in Chlorella on Temperature and Light Intensity

Abstract

The effects of temperature and light on cell division were studied in synchronized suspensions of the high‐temperature strain Chlorella 7–11–05. It was found that the time for incipient cell division, the progress in the process after it started, and the number of cells produced are influenced by temperature and light intensity. Within limits, cell division is generally favored by the increase in temperature. The increase in light intensity first favors cell division then, after the optimal light intensity is attained, a further increase in light intensity inhibits cell division. Observations are discussed in connection with the findings of other investigators. The limitations of cell division by temperature and light intensity are considered to be separate from the effects of these factors on growth.

Synchronous Cultures of Algae

“…It wa s observed that , although the rates of growth and onset of cellular division were markedly temperature-dependent, the division number remained the same (4.0 to 4.1) at the three temperatures tested. A similar temperature-dependency of growth and cellular division was later reported for the high temperature Chlorella, in which, however, the division number markedly increased with the increase in temperature (187). Kinetic analysis of Morimura's results showed that the processes of "ripening" and "postripening" (see Fig.…”

“…Similar results (but with some irregular fluctuations) were later observed with the. high temperature Chlorella in the temperature range of 20° to 40° (187). What was remarkable in Morimura's observations was the difference in the division number which was smaller at lower light intensities.…”

Plants under Climatic Stress

“…Solarization (12), a term coined for the damaging effects of very high light intensities on starch production in the leaves of many plants; high light, low temperature inhibitions of algal growth (24); and the photoinactivation of isolated chloroplasts (13,14) may be phenomena related to effects described in this paper. Reducing photosynthesis by lowering the temperature puts little increased heat-dissipating load on the chloroplast, since 75 to 85% of visible light absorbed by the chloroplastic pigments is lost as heat under even optimal photosynthetic conditions, yet this light under these chilling conditions causes a rapid change in the ultrastructure of mature chloroplasts (25).…”

Influence of aeration and lighting on biomass production and protein biosynthesis in a Spirulina sp. isolated from an oil-polluted brackish water marsh in the Niger Delta, Nigeria

“…Cell division, an aspect of cell growth, is also known to be influenced by light intensity. Sorokin and Krauss (1965) had reported that an increase in light intensity first favours cell division then, after the optimal light intensity was attained, a further increase in light intensity inhibited cell division. Dubey (2006) reported moderate light intensity in the cultivation of Spirulina, suggesting low light intensity at the beginning to avoid photolysis.…”