CYTOLOGICAL AND PADIOAUTOGRAPII£CAL ANALYSIS OF A COLD-INDUCED MITOTIC BLOCKAGE IN THE NEUROBLASTS OF THE GRASSHOPPER CHORTOPllAGA VIRIDIFASCIATA(Do GEER)

摘要

Studies by M. E. Gaulden have shown that embryos of Chortophaga viridifasciata (Do Gcer) kept at 11℃ show no development over a period of several months,. Experiments were designed to study the effect of this temperature on mitosis. After 13 days development at 26℃, embryos were placed in a refrigerator at 11℃. At 4 day intervals three embryos wore removed and the mitotic stage of each visible neuroblast in three segments was determined in hanging-drop cultures. After 40 days exposure to 11℃, over 99％ of the cells were found to be in interphase, as identified by nuclear morphology. The per cent of cells in telophase and in mid-mitosis (prometaphase, metaphase, and anaphase) decreased steadily and reached zero after 16 and 20 days respectively, and all prophase stages except very early prophase after 40 days.