Effect of weightlessness and of artificial gravity on irradiated lettuce seeds.

In our previous studies on board the artificial earth satellite Cosmos 368, the cosmic apparatus Zond 8 and the orbital station Salyut it has been demonstrated that space-flight factors (SFF) have a definite effect on poorly active biological systems, such as dry lettuce seeds. The technical possibilities on board the biosatellite Cosmos 782 (the availability of an on-board centrifuge) allowed us to obtain some new data concerning the mechanisms of the SFF effects. Irradiated seeds of lettuce (Lactuca sativa L.) were exposed in space flight for 22 days either to weightlessness conditions only or to a centrifugal field. Data have been obtained characterizing the cytogenetical and physiological processes in seeds of various series of the experiment. An attempt is made to analyse the role of individual SFF in the changes observed.