[Plant UV-B]
Study on plant responses against the stresses of microgravity and radiation in space

RESEARCH OVERVIEW

• The responses of plants under the stresses of microgravity, high radiation, and composite stress of both microgravity and high radiation are important to understand plant growth in space.
• The Study on Plant Responses Against the Stresses of Microgravity and High Ultraviolet Radiation in Space (Plant UV-B) investigation provides researchers with information about what happens to plants at the molecular and cellular levels, and clarifies the damage, repair, and adaptation mechanism of plants in the space environment.
• This research is positioned as a pioneering study to understand basic plant responses to the space environment, and to develop plant cultivation technologies in space.

DESCRIPTION

The Study on Plant Responses Against the Stresses of Microgravity and High Ultraviolet Radiation in Space (Plant UV-B) investigation analyzes the characteristics/states of plants under the stresses of microgravity, high ultraviolet (UV) radiation (especially UV-B (Wavelength: 280-315 nm)), and both of those in the space environment in order to elucidate the disability against these stresses, as well as the mechanism on how to recover or adapt this disability from the point of molecular, cell, and individual levels. This study utilizes Arabidopsis thaliana for the visualizing the mitochondria and chloroplast. This study uses wild-type and a mutant lacking autophagy function, which plays an important role in stress tolerance of Arabidopsis thaliana. Therefore, this research is positioned as a pioneering study to understand basic plant responses to the space environment, and to establish plant cultivation technology in space.

SPACE APPLICATIONS

Long-term missions to the Moon and Mars require the capability to grow plants in space and limited gravity. This investigation contributes to the development of lunar and space agriculture.

EARTH APPLICATIONS

This investigation could reveal characteristics of plant growth that are masked by Earth’s gravity and provide insight into new technologies for growing plants in stressful environments on the ground.

OPERATIONAL REQUIREMENTS AND PROTOCOLS

Dried seeds of Arabidopsis thaliana (transgenic) are launched to the International Space Station and planted in JAXA's Plant Experiment Unit (PEU) chambers. After watering by the crew, the seeds are incubated for 13 or 15 days under LED illumination using the JAXA Cell Biology Experiment Facility (CBEF). On the 12th day of culture, half of the plants are to be irradiated with UV-B, and one or three days later all plants are harvested and stored in a freezer or fixed chemically.