The Cytological Effects of Space Flight Factors, Vibration, Clinostat and Radiation on Root Tip Cells of Tradescantia

Abstract

Cytological effects of actual and simulated space flight factors, with and without gamma irradiation, have been studied in Tradescantia clone O2. In the Biosatellite II experiment, one package of 32 rooted Tradescantia inflorescences was exposed during the weightless phase to about 220 R of γ-radiation from an ${}^{85}{\rm Sr}$ source, and an unirradiated package was used as a flight control. Two similar packages, one irradiated and the other unirradiated, were maintained in a nonflight vehicle at the Cape Kennedy launch site as nonflight controls. The location of the roots of individual plants within the package relative to the radiation source permitted an exposure-response determination for chromosome aberrations. In the clinostat-radiation experiments dose response data were not obtained. After the treatments, the frequencies of chromosomal aberrations and mitotic spindle abnormalities were studied in root tip cells. A comparison between the irradiated flight and nonflight samples...