Impact of Air Quality on Food Production in Space
- Paper number
IAC-07-A1.6.07
- Author
Mr. Joseph Romagnano, Utah State University, United States
- Coauthor
Prof. Bruce Bugbee, Utah State University, United States
- Year
2007
- Abstract
The mandate to travel back to the moon and on to Mars, by necessity, entails long duration missions. As part of the Advanced Life Support Initiative, NASA has for many years pursued long-term self-sustaining crop plant production technologies. These efforts have been hampered by the accumulation of the plant hormone ethylene in growth chambers; disturbing normal growth. Plants are the main source of ethylene in controlled environment chambers and levels as low as 5 nmol mol-1 (ppb) can reduce yield. Since ethylene is required to regulate developmental change it is important to understand how much ethylene synthesis or sensitivity can be altered without an adverse affect on growth or development. We examined the effects of several abiotic stressors common to microgravity plant hardware: 1. Light: Increased light did not decrease ethylene sensitivity. 2. Drought: Decreased ethylene synthesis occurred until plants were re-watered. 3. Flood-Induced Hypoxia: Plants increased synthesis in response to flood stress. The ratio of the ethylene to CO2 synthesis rates was calculated to determine ethylene synthesis as a function of respiration, which eliminates metabolic rate and plant size as variables. Calculating this ratio allowed us to test the hypothesis that ethylene signaling is tied more to metabolic rate than to plant size. Small rapidly growing plants can produce more ethylene than large, slow growing ones; however, per unit metabolism, they may be identical. We also examined the potential for 1-methylcyclopropene (MCP), a gaseous non-toxic ethylene perception inhibitor, to mitigate ethylene contamination in controlled environment chambers. Although substantial data exists for MCP effects in post-harvest physiology, sparse data is available for whole-plant physiology. MCP increased the respiration and ethylene synthesis for all intact plants tested. This was unexpected given the effects observed in post-harvest physiology. MCP also increased the rate of ethylene synthesis more than respiration. The work was carried out using flow-through gas exchange chambers and steady-state techniques. An automated thermal desorption gas chromatography system, capable of measuring down to picomol mol-1 levels was used to quantify ethylene synthesis rates. This approach, for the first time, allowed whole plant ethylene synthesis to be quantified in a manner that prevented the accumulation of ethylene to detrimental concentrations. Such data is essential for engineers designing plant growth units since ethylene removal systems can now be sized on known plant output.- Abstract document
- Manuscript document
IAC-07-A1.6.07.pdf (🔒 authorized access only).
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