[Experiment with a physiologically active culture of Chlorella on "Soiuz-9" spacecraft]. / Eksperiment s fiziologicheski aktivnoi kul'turoi khlorelly na kosmicheskom korable "Soiuz-9"

A physiologically-active culture of chlorella was for the first time exhibited on board the "Soyuz-9" spacecraft. The use of a special four-socket container made it possible to investigate in one experiment the effect of the factors of a space flight on the cells of algae developing in illumination during 1, 6 and 14 days. Besides that the effect of the flight conditions was studied on the culture of chlorells. Insignificant change in sensitivity of the cells to the effect of the flight factors depending upon the duration of their exposure in the active condition is shown.

Effect of dynamic factors of space flights on the green alga Chlorella vulgaris.

The biological effects of vibrational and linear acceleration on the alga Chlorella vulgaris were studied. Periodic vibration in the frequency range of 4-4000 Hz with vibrational acceleration up to 16 g did not affect the survival and mutability of Chlorella cells and did not modify the effects of acute gamma-radiation. However, random vibration similar to that occurring during launch of spaceships, combined with linear acceleration increased the radiation damage to algae produced by acute gamma-radiation at a dose of 10000 r. This effect is seen only in cells at the beginning of the G1 stage, which precedes DNA synthesis.

Effects of space flight factors on the heredity of higher and lower plants.

The effects were studied of a long-term space exposure (72 days) aboard the Salyut orbital station on the following: dry seeds of Crepis capillaris (L.) Wallr. and Arabidopsis thaliana (L.) Heynh, haploid and diploid strains of Saccharomyces cerevisiae mutant for adenine locus (ad) and strain LARG-I of Chlorella vulgaris Beijer. A modifying effect of space factors on radiobiological action of gamma-irradiation from 137Cs was determined with the higher plant seeds and Chlorella culture. For this, the material was partly irradiated prior to, and partly after the flight at doses of 3, 30 and 10 kr for C. capillaris, A. thaliana and Chl. vulgaris, respectively. It was shown that: (1) Space factors caused reduced survival of Arabidopsis seedlings and Chlorella and yeast cultures, reduced productivity of Chlorella cells, increased mutability of Chlorella and yeast cells and increased frequency of chromosome aberrations in cells of Crepis root meristem. There are, however, a few exceptions: cell germination of C. capillaris was enhanced while mutability of A. thaliana seeds declined. (2) Space factors increased the adverse effects of the pre-flight irradiation on all the parameters of the cultures tested. (3) Space factors had no genetic effect on the objects tested. They have, however, caused a stronger inhibition of seed germination and augmenting survival of A. thaliana seedlings and Chlorella cells.