Biological investigations of higher and lower plants aboard Soyuz 19

Biological investigations carried out aboard Soyuz 19 consisted of three independent complex experiments. All biological materials aboard the spacecraft were kept in "Biocat" thermostats which maintained the required temperature. The objective of the experiment "Genetic investigations" was to determine the effect of space flight factors on the heredity of lower (Chlamydomonas reinhardi Dang) and higher (Crepis capillaris (L) Wallr and Arabidopsis thaliana (L) Heynh) plants, and on the radiosensitivity of plant seeds and the radiation effect of prior gamma-irradiation. The space flight factors decreased the survival of Chlamydomonas cells and A. thaliana plants of the first generation. They decreased the germination of seeds, increased the rate of chlorophyll mutations and embryonal lethals, produced no effect on the rate of visible mutations in unicellular algae, increased the rate of chromosome aberrations in root meristem cells C. capillaris, induced disturbances in mitosis of unicellular algae and modified the effect of prior gamma-irradiation. The experiment "Growth of micro-organisms" was conducted with a culture of Proteus vulgaris in a growth chamber. After return to the laboratory the experimental and control variants were studied for twenty-two tests. The control and experimental material differed in the average cell size, biomass distribution, the character of haemotaxis, the rate of cell migration over the substratum surface, dehydrogenase activity, ribosomal aggregation, and ultrastructural peculiarities of cells. The experiment "Embryological investigations" was carried out to study the effect of space flight factors on embryogenesis of the bony fish Brachyodanio rerio. No abnormalities were noted in the course or rate of the development of spawn cultivated in a special thermostat.