ESJ56 一般講演（口頭発表） B1-04
*Yoshihiko Onda, Kenta Tanaka （Sugadaira MEC, Tsukuba Univ.）
The plant model of molecular biology Arabidopsis thaliana has ecologically diverse wild relatives and they are increasingly interested in the field of evolution and adaptation. We are studying altitudinal adaptation and its ecological constraints in Arabidopsis kamchatica ssp. kamchatica, which is perennial and distributed over wide altitudinal range. We first surveyed herbarium collections and clarified that A. k. kamchatica distribution ranged from 30m to 3000m altitude even in close range (ca. 1 degree) of latitude. We set 20 focal populations at various altitudes in 4 mountain regions (Tsurugi, Norikura, Kiso and Senjo) and 4 supplemental populations at extreme altitude in other mountain regions. We based on previous herbarium collection records (ca. 30-50 years ago) to find wild populations, however, populations at low altitude limit tended not to be found, possibly due to environmental change. Our interim demographic census showed that the local density was higher at high-altitude populations. Some low-altitude populations were subject to high summer mortality, leading to our interest in winter mortality at high-altitude populations. We are currently analysing growth rate. The successive censuses, combined with planned genetic analyses, will show ecological constraints and the role of adaptive evolution in altitudinal adaptation.