The Behavior of Mitochondria in Pollen Mother Cells of Tradescantia reflexa

Abstract

The behavior of mitochondria was studied in pollen mother cells of Tradiscantia reflexa fixed with OsO₄ or KMnO₄ under the electron microscope. Mitochondria were found scattered throughout the cytoplasm in cells in prophase I. But with the break down of the nuclear membrane (prometaphase I), mitochondria were found intruded into the nuclear or spindle area. Besides mitochondria, dictyosomes, lipid granules and even plastids were seen in the spindle. Mitochondria in the spindle area or phragmoplast gradually increased in number with the progress of meiotic stages from metaphase I to early telophase I. In mid-telophase I, most of the mitochondria are aggregated about the equator of the phragmoplast. Vesicles were found among the aggregated mitochondria arranged in a series forming the beginning of the cell plate (late telophase I). By the cell plate formed, the mitochondria are distributed evenly between the daughter cells. The relation between the increase in elements of the endoplasmic reticulum at the boundary of the spindle followed by the break down of the nuclear membrane and the intrusion of mitochondria into the spindle is discussed.