Gallegos GL, Hilaire EM, Peterson BV, Brown CS, Guikema JA.
ASGSB Bull. 1995 Oct; 9: 16.
NSCORT in Gravitational Biology, Kansas State University, Manhattan, USA.
Starch filled amyloplasts, contained within columella cells of the root caps of higher plant roots, are believed to play a statolith-like role in the gravitropic response of roots. Plants having amyloplasts containing less starch exhibit a corresponding reduction in gravitropic response. We have observed enhanced ethylene production by sweet clover (Melilotus alba L.) seedlings grown in the altered gravity condition of a slow rotating clinostat, and have suggested that this may be a stress response from continuous gravistimulation rather than a result of a simulation of a microgravity. If so, we expect that starch-deficient plants may produce less stress ethylene when grown on a clinostat than would wildtype. Arabidopsis thaliana seeds of wildtype and two starch deficient mutants (TC7 and TL25) were germinated and grown in the Fluid Processing Apparatus under three conditions: stationary, clinorotation (2 rpm), and microgravity (space shuttle mission STS-63). All seedlings were fixed at 3 days and gas samples taken and quantified for ethlyene using a gas chromatograph with a flame ionization detector. Contrary to what we have seen in Melilotus, Arabidopsis grown for 3 days on a clinostat did not produce significantly greater levels of ethylene than when grown in the stationary condition. Mutants deficient in starch produced significantly greater levels of ethylene when grown in microgravity than in the stationary or clinostat conditions. This was not shown for wildtype. Clearly, clinorotation was not a simulator of microgravity. These results may suggest further evidence of a change in carbon allocation when plants are grown in microgravity.
Publication Types:
Keywords:
- Arabidopsis
- Ethylenes
- Gravitation
- Plant Roots
- Plastids
- Rotation
- Salicylates
- Seeds
- Starch
- Weightlessness
- Weightlessness Simulation
- bismuth subsalicylate
- ethylene
- NASA Discipline Developmental Biology
- NASA Discipline Number 93-10
- NASA Program NSCORT
- Non-NASA Center
Other ID:
UI: 102222680
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