Effect of High-Doses Ionizing Radiation on Photosynthesis of Wheat Plants at Various Light Intensities

Long-term manned space missions require the design and construction of “space greenhouses” to replenish food supplies and regenerate the atmosphere. Increased levels of ionizing radiation outside the Earth’s magnetosphere can significantly affect the efficiency of photosynthesis, the process by which plants use light energy to synthesize organic matter and produce oxygen. Identifying the mechanisms of the effect of ionizing radiation on photosynthesis and determining the optimal parameters for the operation of space greenhouses can help compensate for the impact of space conditions on plant productivity. This paper shows that irradiation of wheat plants (Triticum aestivum L.) at a dose of 100 Gy significantly increases the rate of plant development and disrupts their ability to use light energy in photosynthesis. A range of illumination intensities was found at which the efficiency of light energy use in irradiated plants coincided with this parameter in control plants. The disruption of the connection between photosystem II and the antenna of the light-harvesting complex caused by oxidative stress is assumed to be the mechanism of the identified imbalance in the functioning of the photosynthetic apparatus.