biology and biotechnology

MOLECULAR AND PLANT PHYSIOLOGICAL ANALYSES OF THE MICROGRAVITY EFFECTS ON

MULTIGENERATION STUDIES OF ARABIDOPSIS THALIANA (MULTIGEN)

Research Area: Plant Biology

Expedition(s): 15 and 16

Principal Investigator(s): ● Tor-Henning Iversen PhD, Norwegian University of Science

and Technology, Trondheim, Norway

RESEARCH OBJECTIVES

Molecular and Plant Physiological Analyses of the Microgravity Effects on Multigeneration

Studies of Arabidopsis thaliana (Multigen) will grow Arabidopsis thaliana, a small flowering

plant related to cabbage and mustard, in orbit for 3 generations. The results of this

investigation will support future plans to grow plants on the long-duration transit to Mars.

RESULTS

In August 2007, seeds were cultivated in experiment containers

on 2 separate rotors in the European Modular Cultivation

System (EMCS), with images taken every 5 minutes. During the

73 day long experiment, 85% of the seeds germinated, despite

interruptions caused by too high air flow on day 7 and

unforeseen power outages.

The gravitropic response to 1 g applied force was greater for the

microgravity grown plants than the 1 g grown plants, with the

leaves curving upwards 30 minutes after the start of the rotor.

At an early growth stage, rosette leaf movements usually bent

down when exposed to light, bent upwards when exposed to

darkness, and included oscillative (swinging) movements. In

light periods, rhythmic leaf movements were present at 45 and

80 minutes. In darkness only 120 minutes rhythms could be

found, but image quality was lower and could have missed

detecting faster rhythms (Solheim et al. 2009).

Side stems showed small movements in microgravity and darkness, as well as pronounced

circumnutations in 0.8 g force (in darkness and light), followed by no movement once the

centrifuge stopped. Although power outages affected the quantity of observations collected,

there was enough data to show the main stem demonstrated small movements in microgravity

and amplified movements under applied acceleration (Johnsson et al. 2009).

PUBLICATION(S)

Johnsson A, Solheim BB, Iversen T. Gravity amplifies and microgravity decreases

circumnutations in Arabidopsis Thaliana stems: Results from a spaceexperiment. New

Phytologist. 2009;182:621-629. doi: 10.1111/j.1469-8137.2009.02777.x.

In-orbit image from first part of
Multigen experiment shows the
flower stalk (stem) with 2-3 flower
bulbs on top and a few stem leaves
below. ESA image.