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The aim of the experiment "Seeds" on the Sowjetic satellite Biokosmos 9 was the observation of mutagenic effects caused at special loci of seeds of Arabidopsis thaliana and assigned to particles of the Cosmic radiation. Two types of exposure units were flown: A low-shielding unit Type I, mounted at the surface of the satellite (1.4 g/cm2 shielding) and, for comparison, an identical item inside (16 g/cm2 shielding), using nuclear emulsion as track detectors. A Type II unit, flown inside (18g/cm2 shielding) was mounted with AgCl track detectors. The layout will be briefly described. A first set of dosimetric data from the physical evaluation of the experiment will be presented. The subdivision into charge- and LET-groups shows a rather high contribution of the intermediate LET-group (350-1000 MeV/cm) due to medium heavy particles (Z = 6-10) and to enders of light (p, alpha) particles.

The effect of cosmic radiation on air-dry lettuce (Lactuca sativa) seeds was investigated. It was attempted to discriminate the effects of cosmic ionizing radiation per se and its combination with solar light radiation. It was found that the number of aberrant cells in the seeds exposed to solar light was smaller than that of cells chielded with 0.0008 to 0.0035 g/cm2 foil which could be attributed to photoreactivity.

This paper presents the results of measuring single heavy ions (HI) of galactic cosmic rays during 40- to 457-day flights of manned orbital stations Salyut-6 and Salyut-7. Cytogenetic analysis of Lactuca sativa seeds showed a significant increase of aberrant cells and cells with multiple chromosome aberrations in seeds hit with HI compared to non-hit++ seeds during flights of 123 to 457 days in duration. There was a good correlation between curves showing aberrant cells as a function of flight of the dose absorbed, viz. 16.0 to 63.4 mGy. These findings suggest a high biological effectiveness of heavy ions of galactic cosmic rays.

The experiment was carried out on lattice (Lactuca sativa) seeds flown in a biocontainer equipped with plastic detectors to record heavy charged particles (HCP). The purpose of the experiment was to determine the yield of aberrant cells as a result of irradiation, and to identify this effect as a function of HCP topography in the seed. The cytogenetic examination of flight seedlings revealed a significant difference between the seeds which were hit with HCP and those that remained intact. This indicates a significant contribution of the heavy component of galactic cosmic rediation into the radiobiological effect. The relationship between the radiobiological effect and the HCP topography in the seed was established: zones of the root and stem meristema proved to be most sensitive targets.