Temperature-induced changes in the nuclear envelope of Euglena and Scenedesmus

Abstract

Euglena and Scenedesmus cells were grown at two different temperatures prior to measurement of the number of nuclear pores per square micron of nuclear surface areas and nuclear volumes. Euglena cells grown at 15°C had a significantly larger nuclear volume, a significantly larger nuclear surface area, and a significantly greater number of pores per square micron of nuclear envelope surface than did Euglena cells grown at 30°C. An estimate of nuclear pores per nucleus showed that on average there were several thousand more pores per nucleus in cells grown at 15°C than in cells grown at 30°C. In Scenedesmus the mean number of nuclear pores per square micron of nuclear surface area was significantly greater in cells grown at 23°C than in cells grown at 15°C. The mean nuclear volumes and surface areas were, however, significantly greater in cells grown at 15°C than in cells grown at 23°C. An estimate of nuclear pores per nucleus indicated no difference between the two growth temperatures for Scenedesmus . The results of these experiments provide further evidence that the nuclear envelope does change in response to growth temperature.