Response patterns of net photosynthesis to moisture of mosses in xeric habitats

  • Takayuki Nakatsubo
  • Yasunori Takamine
  • Yoshio Ino


The response patterns of net photosynthesis to moisture level of mosses in xeric habitats were compared with those in mesic habitats, in order to determine whether the former species are better adapted to the xeric condition with regard to carbon gain.

Moss species examined wereRhacomitrium lanuginosum andR. barbuloides in xeric open habitats andDicranum japonicum, Hypnum plicatulum, Ptilium crista-castrensis, Pleurozium schreberi andHylocomium splendens in mesic habitats on the coniferous forest floor in the upper subalpine zone of Mt. Fuji. Three additional xerophytic species collected at other localities,Ptychomitrium polyphylloides, Grimmia pilifera andHedwigia ciliata, were also examined.

Five species in the xeric habitats showed an optimum range of moisture level for net photosynthesis, 2 to 3g·g−1. On the other hand, species in the forest showed a wider optimum range, 3 to 8g·g−1. Net photosynthetic rate at the moisture level of 0.5g·g−1 was positive in xerophytic mosses, but negative in most forest mosses.

Moisture levels where external capillary water disappeared and drop of water potential began was determined by blotting water-saturated shoots with membrane filters. These moisture levels were low in the xerophytic mosses and high in the forest mosses, although there were some exceptions.

It was concluded that mosses in xeric habitats are better adapted for the efficient use of water for photosynthesis than those in mesic habitats.

Key words

Adaptation Moisture Moss Net photosynthesis Water potential Xeric habitat 


  1. Alpert, P. andW.C. Oechel. 1985. Carbon balance limits the microdistribution ofGrimmia laevigata, a desiccation-tolerant plant. Ecology66: 660–669.CrossRefGoogle Scholar
  2. Busby, J.R. andD.W.A. Whitfield. 1978. Water potential, water content, and net assimilation of some boreal forest mosses. Can. J. Bot.56: 1551–1558.CrossRefGoogle Scholar
  3. Dilks, T.J.K. andM.C.F. Proctor. 1974. The pattern of recovery of bryophytes after desiccation. J. Bryol.8: 97–115.Google Scholar
  4. — and —. 1979. Photosynthesis, respiration and water content in bryophytes. New Phytol.82: 97–114.CrossRefGoogle Scholar
  5. Kallio, P. andS. Heinonen. 1973. Ecology ofRhacomitrium lanuginosum (Hedw.) Brid. Rep. Kevo Subarctic Res. Stat.10: 43–54.Google Scholar
  6. Nakamura, T. 1984. Development of terricolous moss communities in subalpine coniferous forests of Mt. Fuji. J. Hattori Bot. Lab.56: 65–77.Google Scholar
  7. Oechel, W.C. andN.J. Collins. 1976. Comparative CO2 exchange patterns in mosses from two tundra habitats at Barrow, Alaska. Can. J. Bot.54: 1355–1369.CrossRefGoogle Scholar
  8. Proctor, M.C.F. 1982. Physiological ecology: Water relations, light and temperature responses, carbon balance.In A.J.E. Smith, ed., Bryophyte Ecology, pp. 333–381. Chapman and Hall, London.Google Scholar
  9. Stålfelt, M.G. 1938. Der Gasaustausch der Moose. Planta27: 30–60.CrossRefGoogle Scholar
  10. Streusand, V.J., J.A. Weber andH. Ikuma. 1986. Desiccation tolerance in Mosses. II. Differences in the responses ofHedwigia ciliata andMnium cuspidatum to desiccation and rehydration. Can. J. Bot.64: 2393–2398.CrossRefGoogle Scholar
  11. Tallis, J.H. 1959. Studies in the biology and ecology ofRhacomitrium lanuginosum Brid. II. Growth, reproduction and physiology. J. Ecol.47: 325–350.CrossRefGoogle Scholar
  12. Tobiessen, P.L., N.G. Slack andK.A. Mott. 1979. Carbon balance in relation to drying in four epiphytic mosses growing in different vertical ranges. Can. J. Bot.57: 1994–1998.Google Scholar

Copyright information

© The Botanical Society of Japan 1989

Authors and Affiliations

  • Takayuki Nakatsubo
    • 1
  • Yasunori Takamine
    • 1
  • Yoshio Ino
    • 1
  1. 1.Department of Biology, School of EducationWaseda UniversityTokyo

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