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Plant Physiol. 1996 Mar;110(3):801-6.

Growth and photosynthetic responses of wheat plants grown in space.

Author information

  • 1National Aeronautics and Space Administration, and The Dynamac Corporation, Kennedy Space Center, Cape Canaveral, Florida, USA. bct@jnuniv.ernet.in

Abstract

Growth and photosynthesis of wheat (Triticum aestivum L. cv Super Dwarf) plants grown onboard the space shuttle Discovery for 10 d were examined. Compared to ground control plants, the shoot fresh weight of space-grown seedlings decreased by 25%. Postflight measurements of the O2 evolution/photosynthetic photon flux density response curves of leaf samples revealed that the CO2-saturated photosynthetic rate at saturating light intensities in space-grown plants declined 25% relative to the rate in ground control plants. The relative quantum yield of CO2-saturated photosynthetic O2 evolution measured at limiting light intensities was not significantly affected. In space-grown plants, the light compensation point of the leaves increased by 33%, which likely was due to an increase (27%) in leaf dark-respiration rates. Related experiments with thylakoids isolated from space-grown plants showed that the light-saturated photosynthetic electron transport rate from H2O through photosystems II and I was reduced by 28%. These results demonstrate that photosynthetic functions are affected by the microgravity environment.

PMID:
8819868
[PubMed - indexed for MEDLINE]
PMCID:
PMC157779
Free PMC Article
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