THE COINCIDENT DISTRIBUTION OF CALCIUM-RICH MEMBRANES AND KINETOCHORE FIBERS AT METAPHASE IN LIVING ENDOSPERM CELLS OF HAEMANTHUS

Abstract

Chlorotetracycline (CTC) fluorescence was coupled with polarized light microscopic observations of living mitotic endosperm cells of Haemanthus to compare the spatial distributions of Ca2+-rich endomembranes in the spindle with that of the kinetochore fibers during metaphase. In either control cells or in those treated with the microtubule-stabilizing drug, taxol, the metaphase distribution of Ca2+-rich membranes (bright spindle fluorescence) coincides exactly with the distribution of kinetochore-fiber birefringence. [The endomembrane system associated with the mitotic apparatus may function in the regulation of the spindle, most specifically, through the controlled release of sequestered Ca2+.].