Variation in responses to temperature treatments ex situ of the moss Pleurozium schreberi (Willd. ex Brid.) Mitt. originating from eight altitude sites in Hokkaido, Japan

Abstract

Thermal acclimatisations are important for the survival and growth of individuals and populations but seldom studied for different populations of bryophytes. The aims of this study were to (I) investigate if responses to temperature treatments were independent of the site sampled or if the intra- and inter-population variation in responses were larger than the responses to the temperature treatments (control, press, and pulse), and to (II) examine if experimental responses varied, depending on the sampled sites. We collected samples of the circumpolar bryophyte species, Pleurozium schreberi (Willd. ex Brid.) Mitt., originating from eight altitude sites on Mt. Oakan in Hokkaido, Japan, and exposed them to three different temperature treatments ex situ for four weeks. Thermal acclimatisation was estimated by measuring responses in growth length increase, biomass increase, number of branches, and the maximum quantum yield of PS II (Fv/Fm). We found that responses to temperature treatments were dependent on the site sampled, and that differences were most pronounced in the length increase. Results also shows that the responses to experimental treatments may differ between sites. Our results therefore raise important concerns regarding the general validity of both ex situ and in situ experiments when performed on a single or a limited number of sites.

Keywords:

• Alpine
• Biomass
• Environmental stress
• Fv/Fm
• Moss
• Stress

Acknowledgments

This study was supported by the Japan Society for Promotion of Science (P07727). We thank the officer at the Akan National Park for our research permission to work in the area. AKJ also received financial support from Helge Ax:son Johnson foundation and Jubileumsfonden at Göteborg University. We thank Inga-Märit Köhler and Elin Jägerbrand for assistance.

Taxonomic Additions and Changes: Nil.