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The Problem
  		• Tough Environment for Plants in Lunar and Martian Agriculture.
  		• Atmospheric Pressure: Moon-0; Mars-1/100th earth's.
  		• Gravity: Moon - 1/6th; Mars 2/5th earth's.
  		• Day length:
    Moon 29.5 days - 14.8 days in dark.
    Mars - 24 hr. 29 min.
  		• Mars - Atmosphere is 95% CO2; 1/2 light as on earth.
  		• No carbon on Moon (needed for photosynthesis).
  		• Light - can be captured, but will need to be produced artificially.
  		• Travel to Mars and return to Earth is a 3-year process, i.e. you can't cram enough food into a space ship.
  		• Need to incorporate Biogenerative Life Support Systems (recycling using PLANTS and physical-chemical systems), rather than just depending on "Resupply".
  		• Plants also supplement physical/chemical methods of removing Carbon Dioxide (CO2) and producing Oxygen (O2).
  		• Plants are being used as supplemental food source: "NASA's Salad Bar program".


    The Currency of Space
  • POWER -
    		• Energy costs to produce power, i.e. generating light for plants.
  • MASS-WEIGHT -
    		• Very expensive to ship stuff into Space.
    Vacuum of space makes large transport structures difficult to build.


    Plant Growth at Sub-Ambient Atmospheric Pressures
    Advantages of Low Pressure System.
  • Less structure needs to be shipped into space.
  • Less gas leakage from low pressure crop production to vacuum of Moon or near vacuum of Mars.
  • Crew could tend crops without suiting up.
  • Won't have to ship or produce as much Nitrogen gas.


    		•


    A.B.
    C.D.
    Figure 4. (A) Six chambered low pressure growth (LPPG) system; (B) R. Lacey and C-J He starting an experiment lettuce at (C) early and (D) later stage of development under low pressure.


    Figure 3. Effect of low pressure [(LPS) at 50kPa] on growth of lettuce and wheat seedlings. Notice that the lettuce seedling (left) has greater shoot and root growth than the ambient (100 kPa) lettuce plant, whereas the wheat plant (right) is only slightly larger (+10%) at low pressure (He et al., 2003).
    Results of Low Pressure Systems (LPS).

  • Lettuce and wheat can be grown under low pressure.
  • Photosynthesis and stomatal conductance not adversely affected.
  • Accumulation of Ethyene in chambers under ambient pressure reduced lettuce and wheat growth [1 ppb up to 1000 ppb].
  • Lower ethylene production and better plant growth with LPS.
  • Dark Respiration (at night) lower under LPS = greater plant yield.
    		•


    Nursery Crop Physiology Plant Stress Mycorrhizae Plant Propagation Tissue Culture Acclimatization NASA Phytoremediation Sustain. Ag. Systems
    / Biofertilizers

    Dept. Horticulture Sci., HFSB 416, Texas A&M University,
    College Station, Texas 77843-2133. 979-845-4524 (ph)
    979-845-0627 (fax)

    f-davies@tamu.edu
    If you use any of the visual or written materials, please give credit to the source.