Abstract Detail

Developmental and Structural Section

Kiss, John Z. [1], Vandenbrink, Joshua P. [2], Edelmann, Richard E. [3].

Novel insights into phototropism from experiments on the International Space Station.

As sessile organisms, plants must adapt and respond to the changing environment around them. This adaptation is often achieved through growth-mediated movements termed tropisms. Phototropism is the directed growth in response to light, and the final growth form of a plant is determined by the interaction among tropisms. In the microgravity environment of space flight in low Earth orbit, we have had the opportunity to de-couple phototropism from gravitropism. We also were able to study phototropism in reduced gravity by using an onboard centrifuge in a series of experiments on the International Space Station. Thus, the overarching goal of this study was to elucidate the relationship between the phototropic and gravitropic responses at a continuum of fractional or reduced gravity vectors (0, 0.3, 0.5, 0.8, 1g) representative of non-Earth environments. In addition, we wanted to determine the role of phytochromes A and B in the phototropic response using deficient mutants. Interestingly, in contrast to Earth-based studies, our results reveal a novel positive phototropic curvature in response to blue illumination of roots of Arabidopsis seedlings grown in microgravity and reduced-gravity conditions. In addition, previously described positive phototropic responses of roots and hypocotyls to red light were also observed during conditions of reduced gravity. These studies also reveal phytochrome-dependent differences in the phototropic responses to both red and blue light. Understanding the relationships among plant tropisms in microgravity and reduced-gravity environments are important for using plants as part of future long-distance space exploration or interplanetary colonization efforts.

1 - University Of Mississippi, Graduate School, 100 Graduate House, University, MS, 38677, USA
2 - University of Mississippi, Biology, University, MS, 38677, USA
3 - Miami University, Biology, Oxford, OH, 45056, USA

Keywords:
phototropism
gravitropism
space biology
physiology.

Presentation Type: Oral Paper:Papers for Sections
Session: 76
Location: Salon 11/The Shaw Conference Centre
Date: Wednesday, July 29th, 2015
Time: 4:45 PM
Number: 76005
Abstract ID:97
Candidate for Awards:None