Gravity amplifies and microgravity decreases circumnutations in Arabidopsis thaliana stems: results from a space experiment

Abstract

Summary• In a microgravity experiment onboard the International Space Station, circumnutations of Arabidopsis thaliana were studied. Plants were cultivated on rotors under a light:dark (LD) cycle of 16 : 8 h, and it was possible to apply controlled centrifugation pulses. Time-lapse images of inflorescence stems (primary, primary axillary and lateral inflorescences) documented the effect of microgravity on the circumnutations.• Self-sustained circumnutations of side stems were present in microgravity but amplitudes were mostly very small. In darkness, centrifugation at 0.8 g increased the amplitude by a factor of five to ten. The period at 0.8 g was c. 85 min, in microgravity roughly of the same magnitude. In white light the period decreased to c. 60 min at 0.8 g (microgravity value not measurable). Three-dimensional data showed that under 0.8 g side stems rotated in both clockwise and counter-clockwise directions.• Circumnutation data for the main stem in light showed a doubling of the amplitude and a longer period at 0.8 g than in microgravity (c. 80 vs 60 min).• For the first time, the importance of gravity in amplifying minute oscillatory movements in microgravity into high-amplitude circumnutations was unequivocally demonstrated. The importance of these findings for the modelling of gravity effects on self-sustained oscillatory movements is discussed.

Spaceflight Transcriptomes: Unique Responses to a Novel Environment

“…Some of the responses appear directly and are appropriately correlated to certain environmental parameters in the vehicles and support hardware, or are directly attributable to gravity effects, including the absence of convective mixing in microgravity (e.g., Porterfield et al, 1997;Levinskikh et al, 2000;Liao et al, 2004;Johnsson et al, 2009). However, it is also clear that aspects of spaceflight affect the ability of plants to process biological signals from one tissue type, or organ, to another (e.g., Paul et al, 2001;Roux et al, 2003).…”

Flexible imaging payload for real-time fluorescent biological imaging in parabolic, suborbital and space analog environments

“…Systems have been incorporated into both temporarily and permanently installed ISS plant growth hardware such as Advanced Astroculture (Link et al, 2003;Zhou, 2005), Biomass Production System (BPS) (Morrow and Crabb, 2000;Stutte et al, 2005), Plant Generic Bioprocessing Apparatus (PGBA) (Hoehn et al, 1996;Evans et al, 2009), Lada (Sychev et al, 2007;Bingham et al, 2003), European Modular Cultivation System (EMCS) (Brinckmann, 2005;Johnsson et al, 2009), Biolab (Brinckmann, 2005) and the Green Fluorescent Protein (GFP) Imaging System (GIS) within the Advanced Biological Research System (ABRS) (Paul et al, 2012;Levine et al, 2009). Visible light imaging has been implemented in the bulk of these plant growth chambers, but monitoring has also been conducted through infrared and fluorescent means.…”

Preparation and Outline of Space-Based Studies on Gravity Responses and Cell Wall Formation in Plants

“…While the EMCS facility was not problematic in previous space-based studies (Driss-Ecole et al, 2008;Johnsson et al, 2009;Kiss et al, 2008), there were a number of environmental control failures during the CWRW experiments. These resulted in repeated problems with PCC hydration and airflow.…”

“…1). For the CWRW experiments, growth pots with seven mini-lid holes for sowing seeds were used; these are slightly modified versions of ESA's multi-generation Arabidopsis growth in space-1 (MULTIGEN1) pots, which have either three or five holes (Iversen et al, 2002;Johnsson et al, 2009). CWRW PCC assembly and seed integration were performed in a sterile laminar flow hood at the NorwegianUser Support Operation Center (N-USOC) in Trondheim, Norway between January 14 and 24, 2008.…”