Planta

, 223:46

Microgravity effects on thylakoid, single leaf, and whole canopy photosynthesis of dwarf wheat

Authors

    • Space Life Sciences LaboratoryDynamac Corporation
  • O. Monje
    • Space Life Sciences LaboratoryDynamac Corporation
  • G. D. Goins
    • North Caroline A&T University
  • B. C. Tripathy
    • School of Life Sciences, Jawaharlal Nehru University
Original Article

DOI: 10.1007/s00425-005-0066-2

Cite this article as:
Stutte, G.W., Monje, O., Goins, G.D. et al. Planta (2005) 223: 46. doi:10.1007/s00425-005-0066-2

Abstract

The concept of using higher plants to maintain a sustainable life support system for humans during long-duration space missions is dependent upon photosynthesis. The effects of extended exposure to microgravity on the development and functioning of photosynthesis at the leaf and stand levels were examined onboard the International Space Station (ISS). The PESTO (Photosynthesis Experiment Systems Testing and Operations) experiment was the first long-term replicated test to obtain direct measurements of canopy photosynthesis from space under well-controlled conditions. The PESTO experiment consisted of a series of 21–24 day growth cycles of Triticum aestivum L. cv. USU Apogee onboard ISS. Single leaf measurements showed no differences in photosynthetic activity at the moderate (up to 600 μmol m−2 s−1) light levels, but reductions in whole chain electron transport, PSII, and PSI activities were measured under saturating light (>2,000  μmol m−2 s−1) and CO2 (4000 μmol mol−1) conditions in the microgravity-grown plants. Canopy level photosynthetic rates of plants developing in microgravity at ∼280 μmol m−2 s−1 were not different from ground controls. The wheat canopy had apparently adapted to the microgravity environment since the CO2 compensation (121 vs. 118 μmol mol−1) and PPF compensation (85 vs. 81 μmol m−2 s−1) of the flight and ground treatments were similar. The reduction in whole chain electron transport (13%), PSII (13%), and PSI (16%) activities observed under saturating light conditions suggests that microgravity-induced responses at the canopy level may occur at higher PPF intensity.

Keywords

BioregenerationBioregenerative Life SupportPhotosystem IIPhotosystem ISpaceTriticum aestivum L

Abbreviations

BLSS

Bioregenerative Life Support System

BPS

Biomass Production System

BRIC

Biological Research in Canisters

CDS

Communication and Data System

DAI

Days After Imbibition

ISS

International Space Station

KSC

Kennedy Space Center

LN2

Liquid Nitrogen

NASA

National Aeronautics and Space Association

OES

Orbiter Environment Simulator

Pnet

Net Photosynthesis rate

PAR

Photosynthetically Active Radiation

PESTO

Photosynthesis Experiment System Testing and Operation

PGC

Plant Growth Chamber

PPF

Photosynthetic Photon Flux

PSI

Photosystem I

PSII

Photosystem II

QY

quantum yield

STS

Space Transport System

WCE

Whole Chain Electron transport

Copyright information

© Springer-Verlag 2005