Plants, Agriculture and Space

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Plants, Agriculture and Space

• Christopher S. Brown
• Director of Space Programs
• Kenan Institute for Engineering, Technology
  Science
• North Carolina State University
• SpaceTalk, October 9, 2002

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Plants, Agriculture and Space Outline

• Why Plants? Why Biology?
• Plants in Space
• Advanced Life Support Physicochemical and
  Bioregenerative
• A Plan(t) for the Future

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NASAs StrategicEnterprise Goals(NPD 1000.1,
Sept. 2000)

• HEDS and BPR
• Conduct human missions in the solar system
• Space Science
• Enable human exploration beyond low-Earth orbit
• Aero-Space Technology
• Reduce the cost of interorbital transfer by an
  order of magnitude

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The practical feasibility of cheap human voyages
and settlement of the solar system depends on
fundamental advances in biology
and will have a timescale tied to the
timescale of biotechnologya hundred years.
Freeman Dyson 1999. The Sun, the Genome the
Internet, Oxford University Press.
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• What Plants Do
• Release oxygen, remove carbon dioxide
• Transpire water
• Produce food, fiber and pharmaceuticals
• Respond to the environment

Photos from Biology of Plants, 5th edition,
Raven, Evert and Eichhorn, Worth Publ. 1992
Images from USDA-ARS and Biology of Plants,
Raven et al 1992
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Can plants survive and thrive in space?

• Seed and germination
• Orientation
• Growth and development
• Reproduction
• Gene expression
• Metabolism and photosynthesis

Adapted from June 29, 1999 by David Weisner 1992,
Clarion
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LDEF - Long Duration Exposure Facility

• 12 million tomato seeds in space for 6 years.
• Postflight measurement of germination
• Germination
• Flight 73.8
• Gr. Cont. 70.3
• Seeds remain viable in space.

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Seed germination

• Seeds germinate in space.
• Without gravity, the radicle (embryonic root)
  will continue to grow in the direction of
  emergence.

Lentil seeds in space
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Which way is up?

• Gravitropism tells us that shoots grow up and
  roots grow down.
• Which way will they grow in space?

Arabidopsis floral stalks after 4 hours on their
side.
Photo- S. Wyatt
Photo - Dr. Sarah Wyatt
Soybean seedilings after 8 days in space
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Arabidopsis thaliana
Kiss et al. 1998. Physiol. Plant. 102492-502

• Space shuttle (10 days)
• Strains with dif. amounts of starch
• On-board centrifuge
• Amount of Degree of Hypocotyl
• Starch Curvature after 60 min x 1 g
• Normal 9.5
• Intermediate 1.7
• Intermediate 0.7
• None 0.0
• Conclusion - Strain with the greatest amount of
  starch responded to gravity, which supports the
  starch statolith theory.

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Leaf structure Musgrave et al. 1998. Ann. Bot.
81503-512 Arabidopsis thaliana, 11 d in space,
postflight fixation, STS-68
Ground
Flight
No significant differences in leaf structure
between flight and ground controls. No
differences in membrane structure.
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Plant structural materials

• Cellulose and lignin are important in plant
  structural support
• Reduced amounts of cellulose and lignin were
  found in space -grown mung bean, oat and pine
  (1).
• Bacterial cellulose structure was altered during
  parabolic flight (2).

Mung beans grown for 8 days on the Space
Shuttle (1)
1. Cowles et al. 1984. Ann. Bot. 54 (sup.)
3033-48. 2. Brown et al. 1992. Am. J. Bot.
791247-1258.
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Plant structural materials cont.
Ground Control

• Wheat seedlings
• 10 d in space
• Primary root cell wall cellulose
  microfibrils showed nsd
• Roots grew down into agar
• Roots had normal vessel development and
  thickening patterns
• Plant size similar

Microgravity
0.25 micron
Cellulose microfibril organization in outer
strata of cortical parenchyma cells of wheat
primary roots
Levine, LH et al 2001 Phytochemistry 57835-846
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Tuber formation Solanum tuberosum leaf
cuttings, 16 d mission. Tubers formed
normally. Tuber structure similar. Starch
amounts the same but space tubers had more
grains that were smaller in size. Croxdale
et al. 1997. J. Exp. Bot. 482037-2042.
Volume 48 (317) December 1997
SPACE
GROUND
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Seed pod (silique) formed in space
Arabidopsis, 11 d in space
Flowers formed in space were normal in appearance
Pistil of flower grown in space
Pre-flight STS-68
Pollen germinated and pollen tubes grew towards
style
Ovules from siliques formed in space
Post-flight, 11 d

• Arabidopsis reproduction proceeded normally
  through the stage of an immature seed (STS
  experiments)
• Brassica completed life cycle (Mir space station)
• Past failures and/or diminished growth were
  probably due to less than adequate horticultural
  conditions

Musgrave et al. 1997. Planta 203S177-S184 Musgrav
e et al. 2000. Planta210400-406
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Gene Expression / Stress Physiology
Paul et al 2001. Plant Physiol 1261-9





Arabidopsis thaliana STS-93, PGIM-01, 7-12 d old
plants, Adh gene promoter GUS reporter gene.

Flight


Ground Controls

Whole Plant
Root Tip
Adh/GUS activated in flight roots, not identical
to GC inductions. No apex staining in flight
plants, but staining in GC inductions.
Shoot Apex
Either Normal hypoxia response signaling is
altered in space plants Space induces Adh/GUS
for reasons other than hypoxia.
 
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Metabolism

• Glycine max, 8 d in space
• Decreased starch concentration.
• Lower starch synthetic enzyme activities
• Altered starch grain properties (slower
  degradation, increased amylose).
• Ethylene levels doubled in space.

Soybean seedling grown in space
Temple of Apollo at Delphi DeBoer 2001. Geology
29707-10
Brown et al. 1999. Grav. and Space Biol. Bull.
1377.
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Photosynthesis

• Triticum aestivum, 9 days in space, measurements
  postflight.
• Oxygen evolution dec. 25
• Dark respiration dec. 27
• Electron trans. dec. 28
• Light comp. pt. inc. 33
• Photosynthesis is affected (reduced), but
  measurements must be done in space.

Wheat leaves grown for 9 days in space.
Tripathy et al. 1996. Plant Physiol. 110801-806.
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PESTO - Photosynthesis Experiment System Testing
and Operation.
Triticum aestivum plants at different stages of
growth ISS 4/8 6/19 2002, 73 days In-flight
measurements gtgas exchange gttranspiration
Post-flight measurements gtgrowth
morphology gtcarbohydrates
gtphotosynthesis gtgene expression G. Stutte,
O. Monje, B. Tripathy, G. Goins, D. Chapman
Wheat seedlings grown in prototype hardware for
space experiments
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FD1
FD8
BPS on the ISS
Slide G. Stutte
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• Ground control and flight plants
• were substantially similar wrt
• Germination
• Growth
• Root distribution
• Photosynthetic rates
• Spent years developing the
• hardware (BPS Orbitec) and
• the horticultural protocols
• (Dynamac, NASA).
• Microgravity does not appear
• to be a show-stopper.

Wheat at 21 DAP in flight
Slide G. Stutte
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Plants in space What have we learned?

• Starch statolith theory of gravity perception
  appears to be valid.
• Plant structures form normally and produce viable
  seeds in space.
• Photosynthesis may not be reduced in space-grown
  plants.
• Plants undergo alterations in gene expression in
  space as a result of stress.
• Some metabolic pathways are affected by space.
• Under proper horticultural conditions, plants
  grow and function in space and can be used in the
  mission to explore the solar system.

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Why do we study plants in space?
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Advanced Life Support

• What - Air, water and food
• Why - Ensure mission success
• How - Physicochemical
• How - Bioregenerative

Goal is to minimize Mass (volume) Energy
(power) Crew time
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Space Missions and Durations

• Mission Distance Mission Duration
• Shuttle Low Earth Orbit 7 - 20 days
• ISS Low Earth Orbit human stays 3-12
  months
• Lunar Lunar Orbit days to months
• Libration pts. Lunar and Solar months to
  years?
• Mars Ref. Mars Orbit 3 years (500
  days on
• Mission surface)
• Extended Mars Mars Orbit 10 - 15 years
• Mission
• Asteroids Varies 3 - 10 years?

Estimates based on current propulsion
technologies.
Slide R. Wheeler
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Mass (Consumable) Requirements for Life Support

• Without Water With Water
• Recyling Recyling
• (kg / person) (kg / person)
• Shuttle (10 days) 310 10
• ISS (90 days) 2,790 135
• Mars (1000 days) 31,000 1500

Slide R. Wheeler
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Physicochemical Technologies
Air O2 generation Static water feed
electrolysis CO2 removal Four bed
molecular sieve CO2 reduction Bosch reactor
Water Recycling Potable Multifiltration and
Bosch Hygiene Ultrafiltration and reverse
osmosis Urine Thermoelectric integrated
membrane evaporation
Food - ???
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• What Plants Do
• Release oxygen, remove carbon dioxide
• Transpire water
• Produce food, fiber and pharmaceuticals
• Respond to the environment

Photos from Biology of Plants, 5th edition,
Raven, Evert and Eichhorn, Worth Publ. 1992
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Plants and Bioregenerative Life Support
metabolic energy
HUMANS food (CH2O)
O2 CO2 H2O Clean Water
Waste Water
food (CH2O) O2 H2O
CO2 2H2O Clean Water Waste
Water PLANTS
light
Ferl, Wheeler, Levine and Paul, 2002. Curr. Op.
Plant Biol. 5258-263
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Plants for O2 Production and CO2 Removal
20 m2 Stand of Soybeans
Wheeler 1996 in Plants in Space Biology, Tohoku
University Press
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Breakeven Point
Adapted from R.L. Olson, NASA Contract
NAS2-11148 Final Report, 1982
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As mission duration and distance increase, the
economics of a bioregenerative life support
system improve.
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Current Food Provisions
Supplemental Vegetables ! ?
- fresh foods - bright light - aromas - humidity
Could plants have a positive impact on humans
? Yes!
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Selecting Crops for Space

• High yielding, fast growing
• Nutritious biomass (carbohydrate and protein)
• High harvest index (i.e., ratio of edible to
  inedible)
• Food processing requirements
• Palatability
• Low-growing / dwarf cultivars
• Horticultural requirements
• planting, water and nutrients, pollination,
  harvesting
• Environmental requirements
• light intensity, photoperiod, temperature, CO2
• Genomically manipulable

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Candidate crops for bioregenerative life support
systems
Staple Wheat Soybean White potato Sweet
potato Peanut Rice Quinoa Dry bean/Pea Sugar beet
Supplemental Lettuce Kale Tomato Onion Spi
nach Carrot Radish Broccoli Strawberry Cabbage
Chard/Beet Melon Chufa
Image USDA-ARS
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1
2
3
4
5
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Space Horticulture

• Water and nutrients
• Hydroponic culture
• Solid media
• Hybrid
• Atmosphere
• Temperature 15 30 C
• CO2 1000 2000 ppm (0.1 0.2 kPa)
• RH 60 85
• Ethylene and other VOCs
• Light
• Quality and Quantity
• Photoperiod
• Shading
• Heat and power
• Avoid introduction of any pathogens

Maximize g m-2 d-1 edible biomass !
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Nutrient Film TechniqueA Low-Volume Approach
for Recirculating Hydroponics
Porous Tube Technology -- A nutrient delivery
Concept for microgravity
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Crop Yield vs. PAR (light)
Wheeler et al. 1996. Adv. Space Res.
18(4/5)215-224
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In developing a bioregenerative life support
system, we have been striving to use terrestrial
plants in space by engineering a suitable
environment.
To succeed in the long run, we must return to
the original paradigm of agriculture, which is
selecting plants to fit the environment.
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Programmable Plants for Human Life Support
www.niac.usra.edu/studies Brown 2001.
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What is a Programmable Plant?

• Able to receive input (instructions)
• Able to process information
• Able to transmit data
• Designed for specific purposes (tunable)

Exploit natural components e.g. phytochrome,
signaling pathways, fluorescence, biodiversity
Genomically manipulable and controllable Utilize
implanted nanodevices e.g. sensors,
communication, control
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cbrown_at_ncsu.edu
Yarinks and Drucker,1999