Cultivation of plants in space: their contribution to stabilizing atmospheric composition in closed ecological systems.

Higher plants in biological life support systems (BLSS) not only supply man with food, accomplish recirculation of major gases (CO2 and O2) and reclaim water, they also help remove toxic impurities produced by the ecological system components from the atmosphere of the system. Experiments to study the effect of SO2 on mixed canopies of agricultural plants with pulsing and continuous supply of gas into a sealed volume of the ecosystem showed that gaseous toxic substances can be a) passively absorbed by biologically inactive components of the system, b) actively absorbed and processed by plants. Passive absorption can be described by kinetics with saturation, active absorption--by enzymatic kinetics equations. Parameters of the mathematical model describing removal of toxic substances from closed ecosystem atmosphere can be used to characterize integrally the so-called absorptive properties of the system. Recorded intensity of visible photosynthesis of cenosis showed to be existent such rates of continuous supply of toxic substances into CES that do not essentially damage biological components of the system.