NASA says it is conducting plant research aboard the International Space Station because life in space may depend on it during future long-duration missions. Using plants to provide a food source and to recycle carbon dioxide into breathable oxygen may prove critical for astronauts who will live in space for months at a time, the space agency said in a release Tuesday. Several plant-growing experiments have been conducted to help scientists understand the impact of zero gravity conditions on plant growth, NASA said. Plants can provide a sense of well-being, scientists said, noting that at the McMurdo Station for research in Antarctica -- a site that in the dead of winter mirrors the space station in its isolation, cramped quarters, and hostile environment -- the most sought after section of the habitat is the greenhouse. Both NASA and the European Space Agency have conducted plant research on the ISS, with several future experiments planned. One aim of the experiments, scientists said, is to identify specific plants that are better able to withstand long duration spaceflight and microgravity conditions.