A device to study the effect of space radiation on photosynthetic organisms.

ABSTRACT

This research concerns the study of the effects of ionising space radiation on the oxygen-evolving activity of algae and cyanobacteria, focusing our attention on Photosystem II (PS-II), the oxygen-evolving complex. These microorganisms as higher plants, can use light energy to split water molecules and evolve oxygen in a process that produce storable energy-rich products from atmospheric carbon dioxide. Algae and cyanobacteria which can grow in the presence of nutrients and carbonate are expected to be utilised to maintain an oxygen-atmosphere and to constitute biomass in space shuttles. Irradiation was performed in gamma 60Co-sources of different activities; fluorescence techniques in vivo and SDS-PAGE analysis in vitro were used to determine PS-II efficiency during radiation stress. We determined the radiation target on PS-II by immunoblot. We built a miniaturised growth box that preserves constant pressure and temperature to measure automatically photosynthetic activity by a fluorescence sensor, directly in space during a mission in an ASI balloon.