C4 Photosynthesis in Space Advanced Plant Experiment-9 (APEX-9)

C4 Photosynthesis in Space (C4 Space) (Advanced Plant Experiment-09 or APEX-09) examines the carbon dioxide capture mechanisms of two types of grasses, Brachypodium distachyon and Setaria viridis.  Results could show how photosynthesis and overall plant metabolism change in space. This knowledge could support development of ways to use carbon metabolizing plants in bioregenerative life support systems on future missions.

Experiment launched to the International Space Station (ISS) on the NG-21 Commercial Resupply Service mission in August 2024.

C4 Photosynthesis in Space (C4 Space) (APEX-09) examines how microgravity affects C3 and C4 plant metabolism. Plants capture atmospheric carbon dioxide (CO₂) and convert it into oxygen (O₂) and sugars through photosynthesis. C3 and C4 plants have two different CO₂-concentrating mechanisms. The APEX-09 investigation seeks to compare the impact of conditions aboard the International Space Station on C3 and C4 metabolism using Brachypodium distachyon, a C3 model grass, and Setaria viridis, a C4 model grass. Results from this investigation provide the research team with a better understanding of the C3 and C4 metabolic reprogramming occurring in space environments as compared to on Earth.

Additionally, APEX-09 supports NASA’s efforts for evaluating the potential of growing small-stature cereal and vegetable crops for bio-generative support during future deep space exploration missions.

Results from this investigation provide fundamental insight into plant metabolism in space and could increase understanding of how carbon-fixing plants may be used in bioregenerative life support systems for future space exploration missions.

This investigation provides fundamental insights into photosynthesis and carbon metabolism in space, knowledge that could expand and improve the uses of these plants on Earth.

Space Station Research Explorer