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					Preserving life of moss Ptychomitrium under very high pressure

M. Shindou1, N. Nishihira1, M. Saigusa2, F. Ono3, Y. Matsushima4, Y. Mori3, K. Takarabe3, N. L. Saini5, M.
  Okayama Ichinomiya High School, Okayama 700-0005, Japan
  Department of Applied Science, Okayama University of Science, 1-1 Ridaicho, Okayama 700-0005, Japan
  Department of Physics and 4Department of Biology, Okayama University, 3-1-1 Tsushima-Naka, Okayama
700-8530, Japan
  Dipartimento di Fisica, Universita di Roma “La Sapienza”, Piazzale Aldo Moro 2, 00185 Rome, Italy
  Department of Space Biology and Microgravity Sciences, The Institute of Space and Astronautical Science,
Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510, Japan

 It was shown by the present authors group [1] that a tiny animal tardigrade can survive under high pressure of
7.5 GPa for up to 12 hours. In the case of plants, however, no such experiment has ever been reported. We
have extended our experiments to moss Ptychomitrium searching for lives under extreme conditions of high
hydrostatic pressure.
 Three spore placentas of moss Ptychomitrium were sealed in a small Teflon capsule together with a liquid
pressure medium of Fluorinate. The capsule was put in the center of a pyrophillite cube. This cube was
compressed by six WC-Co second stage anvils with the front edge length of 4.0 mm. These anvils were
compressed by a first stage 250-ton press.
 The pressure was increased from ambient pressure to the maximum pressure of 7.5 GPa at a rate of 0.3
GPa/min. The pressure was kept constant at the maximum pressure for12, 24 and 48 hours, and then,
decreased down to the ambient pressure with the same rate.
 After the pressure was released, they were seeded on a ager medium, and cultured for 5-7days at 25 ℃ with
white light of 3000 lux.
 It was proved that 80-90% of the spores were alive and germinated after exposed to the maximum pressure of
7.5 GPa for up to 42 hours. This high value of germination rate was kept up to the maximum length of the
exposure time of 6 days under 7.5 GPa. The pressure tolerance of moss is found to be much stronger than in
the case of tardigrades.

 [1] F. Ono, M. Saigusa, T. Uozumi, Y. Matsushima, H. Ikeda, N. L. Saini, M. Yamashita, J. Phys. Chem. Sol.
69 (2008) 2297.

Fig.1 Ptychomitrium spore placentas in a Teflon           Fig.2 Germinated Ptychomitrium spore exposed to
capsule after exposed to 7.5 GPa.                         7.5 GPa for 6 days and 2 weeks after seeded.

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