Abstract Detail

Physiology

Vandenbrink, Joshua [1], Herranz, Raul [2], Madina, F. Javier [2], Kiss, John Z. [3].

A Novel Phototropic Response of Arabidopsis thaliana Roots to Blue Light Identified in Microgravity.

Due to their sessile nature, plants have evolved mechanisms to response to changes in environmental factors. Growth-mediated responses, or tropisms, to environmental stimuli direct growth towards or away from a stimulus. Two environmental cues that play a large role in plant growth and development are light and gravity. However, currently very little is known about the interaction between these two tropistic movements. Utilizing the European Modular Cultivation System (EMCS) on board the International Space Station, we investigated the interaction between phototropic and gravitropic responses in three Arabidopsis thaliana genotypes, Lansberg wild-type and phyA and phyB mutants. Utilization of centrifuges on board the EMCS allowed for the simulation of fractional or reduced gravity vectors ranging from 0.1 to 1 g. Under conditions of microgravity, a previously uncharacterized positive blue-light phototropic response was observed in roots exposed to blue light. This phototropic response was attenuated at the onset of gravity (0.1 g). In addition, a red-light positive phototropic curvature was observed in roots exposed to red light. Unlike the blue-light phototropic response, red light curvature of roots showed a gradual decline in curvature in response to increasing the gravity vector. This relationship between magnitude of red light phototropic curvature and the increasing gravity vector appears to be linearly correlated. In addition, the previously characterized red light positive curvature of hypocotyls was confirmed. To our knowledge, this is the first characterization of this positive blue light phototropic curvature in Arabidopsis roots, as well as description of the relationship between these phototropic responses and fractional gravity.

Related Links:
NASA Seedling Growth Experiments

1 - University of Mississippi, Biology, University, MS, 38677, USA
2 - Centro de Investigaciones Biológicas , Madrid, Spain
3 - University Of Mississippi, Graduate School, 100 Graduate House, University, MS, 38677, USA

Keywords:
Space Biology
Physiology
Tropism
Arabidopsis
Phototropism
Gravity.

Presentation Type: Oral Paper
Session: 9, Physiology
Location: 104/Savannah International Trade and Convention Center
Date: Monday, August 1st, 2016
Time: 2:00 PM
Number: 9003
Abstract ID:656
Candidate for Awards:None