Studies of protoplasmic structure in spirogyra

Summary

By means of centrifugal accelerations the chloroplasts in cells ofSpirogyra were moved through the cytoplasm 2, 3, 4, 5, or 15 times. Each time the chloroplasts moved through the cytoplasm their rate of movement was increased and, hence, the apparent consistency of the cytoplasm was decreased. On the basis of the above evidence, it was concluded that the cytoplasm inSpirogyra cells is an elastic fluid.

Some cells in filaments ofSpirogyra were killed by cutting, by heating, or by applying 50 % ethyl alcohol. The filaments were then centrifuged with accelerations which did not cause any displacements of the chloroplasts in most normal filaments. Because the chloroplasts were displaced in groups of cells adjacent to killed cells and were not displaced in more distant cells, it was concluded that impulses were generated in the killed cells which decreased the elasticity of the cytoplasm in nearby cells. Following the initial decrease in elasticity there was a gradual recovery which required more than 40 minutes.