ASGSB 2003 Annual Meeting Abstracts
ANALYSIS OF BRASSICA
VEGETATIVE AND REPRODUCTIVE MATERIAL PRODUCED ON ISS.
Kuang1, M.E. Musgrave2, and R. Morrow3.
1Biology Department, University of Texas Pan American, Edinburg, TX;
2Department of Plant Science, University of Connecticut, Storrs,
CT, 06269; and 3Orbital Technologies Inc., Madison, WI.
During a hardware test of the Biomass Production System plant growth hardware
on ISS, Brassica rapa cv. Astroplants were grown, pollinated, and seeds
were produced prior to harvest at 39 days after planting. The material was
frozen or fixed on orbit and subsequently analyzed in our laboratories. Gross
measures of growth showed comparable performance by the plants in spaceflight
and ground control treatments. Amounts of chlorophyll, starch and soluble
carbohydrates in leaf tissue frozen on orbit were indistinguishable from the
ground control. Despite comparable vegetative growth in 1-g and microgravity,
attributes of the immature seeds produced during spaceflight and fixed or
frozen in flight were significantly different from the ground controls.
Because we had access to frozen material, it was possible for the first time
to perform biochemical analyses on immature seed tissue that had been produced
in microgravity. The immature seeds from the spaceflight treatment had higher
concentrations of chlorophyll, starch, and soluble carbohydrates than the
ground controls. Seed protein was significantly lower in the spaceflight
material. Microscopy of immature seeds fixed in flight showed embryos to be at
a range of developmental stages, while the ground control embryos had all
reached the premature stage of development. Storage reserve deposition was
more advanced in the ground control seeds. The results demonstrate that
although vegetative growth of the Brassica plants was well supported by
the BPS hardware, the spaceflight environment poses special problems for
development inside closed reproductive structures.
(Supported by NASA and Orbitec)
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