STUDY INTO THE INTERACTION OF EFFECTS OF LIGHT AND GRAVITY ON THE GROWTH PROCESS OF
PLANTS (GRAPHOBOX)
Research Area: Plant Biology
Expedition(s): 8 and 9
Principal Investigator(s): ● Karel Buizer, University of Utrecht, Utrecht, Netherlands
RESEARCH OBJECTIVES
The Study into the Interaction of Effects of Light and Gravity on the Growth Process of Plants
(GraPhoBox) experiment investigates the presence of a link between phototropism (growth
towards a light source) and gravitropism (growth towards the gravitational vector) in wild-type
and mutant seeds of Arabidopsis thaliana. The results obtained from the GraPhoBox
experiment can give new insights to the interactions between the mechanisms underlying the
formation of the basic architecture of the plant, and can also give rise to new ideas in how
plants respond to their environment.
RESULTS
The angle of directional growth of roots and shoots
was assessed. Light is—even in the absence of
gravity—the most important environmental cue for
directional growth of shoots, while for roots,
gravity is by far the most important cue, and light is
only a very minor factor due to their poor
phototropic capacity. Compared to roots, shoots
were deviated more than roots in microgravity and
therefore less gravity-dependent. All results
together suggested that environmental cues were
perceived differently by roots and shoots, which
also adapt differently. Furthermore, environmental
cues were probably transferred little or none to the
opposite side of the plant.PUBLICATION(S)
Buizer K. GraPhoBox: Gravitropism and
phototropism in Arabidopsis thaliana. Microgravity
Science and Technology. September 2007;19(5-
6):239-243. doi: 10.1007/BF02919490.This investigation is complete and all results are published.
ESA astronaut André Kuipers works on the
GraPhoBox experiment aboard the International
Space Station. ESA image.