The Behavior of Mitochondria in Pollen Mother Cells of <i>Tradescantia reflexa</i>

Abstract

Several types of behavior of mitochondria during cell division are known. Wilson (1925) describes two types. In one type, mitochondria become ag gregated about the spindle and are cut transversely during telophase. In the other type he describes, mitochondria remain scattered throughout the cytoplasm and pass undivided towards the poles. Other types have been found in plant cells. In Larix (Devise 1922, Prosina 1928 and Hemero callis (Sienica 1929) mitochondria begin to gather around the nucleus in prophase.In metaphase and anaphase the mitochondria are found around the spindle, and in late telophase around each daughter nucleus. In Equisetum (Lewitsky 1925, Jungers 1934 and Nephrodium (Yamanouchi 1908, Senjaninova 1927) mitochondria, which were scattered throughout the cytoplasm in pro-, meta-, and ana-phase, became intruded into the equa torial region of the cell, between daughter nuclei. The observations de scribed above on the behavior of mitochondria during cell division were all made using a light microscope. Few studies such as the present ones have been carried out using an electron microscope, although the structure and nature of the mitochondria have been studied intensively.While studying the fine structure of meiotic cells, a different type of behavior of mitochondria from the above types was found in the pollen mo ther cells of Tradescantia reflexa.This type may throw some light on the problem of disappearance of the nuclear membrane during prometaphase. Materials and methodsPollen mother cells of Tradescantia reflexa in the first meiotic division were fixed for 3 hours in the refrigerator with 1% OsO4 adjusted to pH 8.04 with phosphate buffer, and to isotonicity with sucrose. Materials were de hydrated rapidly with an ethanol series up to 70% ethanol and then with methanol and were embedded in methacryl resin. Some materials were fixed for 1 hour with 1% KMnO4, adjusted to pH 8.04 with phosphate buffer. Materials fixed with KMnO4 were dehydrated in a methanol series and