ASGSB 1999 Annual Meeting Abstracts

ETHYLENE SENSITIVITY OF CROP PLANTS: IMPLICATIONS FOR ADVANCED LIFE SUPPORT AND SPACE FLIGHT. S.P. Klassen, B. Bugbee, and W.F. Campbell. Crop Physiology Lab, Utah State Univ, Logan.

Crop plants are adapted to ethylene levels less than 5 ppb, but levels well above 1 ppm have been measured on MIR. Complete sterility in wheat has been associated with elevated ethylene levels in tightly sealed growth chambers on MIR and at NASA-JSC. However, few controlled studies have been done to clearly implicate ethylene. We examined ethylene levels from 0.25 to 20 ppm on wheat in replicate growth chambers and compared the effects to control chambers without ethylene. A single treatment received 1 ppm ethylene prior to anthesis and no ethylene following boot stage. There was no effect on the rate of development and plants grew well at 20 ppm ethylene, but plant height decreased as ethylene increased. Seed set was reduced at all ethylene levels except the pre-anthesis treatment. Longitudinal leaf rolling (into cylinders) appears to be a sensitive indicator of ethylene pollution in closed chambers. The results of a current study examining ethylene levels down to 0.05 ppm on wheat and rice will also be presented. These studies are an essential prerequisite to the design and sizing of ethylene scrubbing equipment for bioregenerative life support. (Supported by the NASA Advanced Life Support Program administered by the Johnson Space Center, and by the Utah State Agricultural Experiment Station.)

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