Several carbon capture mechanisms have emerged in plant systems that provide unique advantages to plants depending on their environment. For example, while most plants use C3 photosynthesis, C4 and…

North Carolina State University received a $93,601.95 research grant from a civilian federal agency (Shared Services Center) awarded on December 8, 2022, to investigate how elevated carbon dioxide levels affect plant physiology and nutritional content in edible microgreens. The research will examine three distinct photosynthetic mechanisms—C3, C4, and Crassulacean Acid Metabolism (CAM)—to determine which mechanisms provide advantages for enhancing plant productivity in space environments. By monitoring physiological characteristics and nutritional profiles across varying CO2 levels and spaceflight-relevant stressors such as water availability, the project aims to provide baseline information essential for planning long-term space missions. The work is conducted at NC State's facility in Raleigh, North Carolina, with a completion deadline of December 31, 2024, and carries no set-aside designation.

This research directly supports NASA program goals outlined in the Decadal Survey Priority 3, which calls for systematic plant biology experiments to elucidate how plants respond and adapt to spaceflight conditions and to facilitate their integration into bioregenerative life support systems. The project addresses two key NASA research questions: how gravity affects plant growth, development, and metabolic processes such as photosynthesis, and how horticultural approaches can optimize plant cultivation in space. As a prominent Land Grant research institution with extensive experience in agriculture, environmental science, and biotechnology, NC State is well-positioned to deliver the scientific expertise required to advance human spaceflight capabilities through bioregenerative systems research.

Several carbon capture mechanisms have emerged in plant systems that provide unique advantages to plants depending on their environment. For example, while most plants use C3 photosynthesis, C4 and crassulacean acid metabolism (cam) carbon capture mechanisms can increase water use efficiency or temperature tolerance. These advantages have been well-characterized in the atmospheric CO2 levels on earth, but in enclosed human habitats such as those needed for long-term space flight, CO2 levels far exceed that of the earth s atmosphere. Altered CO2 levels are known to affect nutritional content and water use efficiency, however, much of the prior research has used CO2 levels below that on enclosed human habitats. This proposed work would examine how high CO2 levels affect plant physiology and nutritional content of edible microgreens that use different photosynthetic mechanisms: C3, C4, and cam. We will monitor physiological characteristics and the nutritional profile across different CO2 levels for select microgreen species (with C3, C4, and cam photosynthesis). The combined effects of altered CO2 levels and other spaceflight relevant stresses such as water availability will be examined to understand if these different photosynthetic mechanisms can provide advantages to enhance plant productivity in space environments. These results would provide important baseline information on plant nutrition and performance that is needed for planning long term space missions and thus would address the following objectives of the solicitation and NASA program goals: decadal survey- priority 3: a systematic suite of plant biology experiments to elucidate mechanisms by which plants respond and adapt to spaceflight, and to facilitate their eventual use in bioregenerative life support systems PB-1 how does gravity affect plant growth, development & metabolism (e.g. photosynthesis, reproduction, lignin formation, plant defense mechanisms) and PB-3 how can horticultural approaches for sustained production of edible crops in space be both improved and implemented (especially as related to water and nutrient provision in the root zone)?