Scientists from USDA Agricultural Research Service and cooperators launched
samples of green algae Chlamydomonas reinhardtii into outer space to study
some of the key mechanisms that govern plant growth and photosynthesis.

During photosynthesis, a protein-pigment complex known as Photosystem II
must be constantly fixed to repair the damage caused by sunlight and
ultraviolet radiation. ARS plant physiologist Autar Mattoo and the rest of
the research team wanted to evaluate the effects of microgravity, cosmic
rays, high energy particles, and the ionizing radiation of space on the PSII
complex, photosynthesis, and plant growth.

The alga are placed in airtight photo cells and launched into the space in a
Soyuz space capsule where the alga stayed for 15 days. Results showed that
some conditions of the space environment inhibited the ability of the
control algae and two of the four mutant strains to photosynthesize and
grow, both in space and later when they were brought back to Earth. However,
two other mutant strains flourished, both in space and when they were back
to Earth.

[www.ars.usda.gov]