2.1. Study site and plant material
Changbai
Mountain is generally recognized as the highest peak in northeast China
and eastern Eurasia,
with
obvious mountain climate characteristics. This environment is locally
variable as small changes in altitude can lead to large changes in
temperature, humidity, exposure, and other types of changes(X. Yang &
Wu, 1998). The alpine region on Changbai Mountain is the southern
boundary of alpine tundra in east Eurasia.
The
varied topography, weather, soil and other
natural
conditions have created rich biodiversity and vertical zonal
distribution of vegetation on Changbai Mountain,
which
has more than 2,277 species of plants and a notable richness of endemic
species.
From 2012 to 2014, fresh leaves were collected from 461 individuals
belong
to 36 nature populations of R. aureum along an environmental
transect which altitude range from 1200m to 2600m a.s.l., annual mean
temperature range from 0.1
°C
to -6.6 °C and annual precipitation range from 761 mm to 1096 mm(Table 1, Figure C) . These populations were scattered along
peaks of Changbai Mountain (32 populations), Laobai Mountain (2
populations), and Wangtian’e Mountain (2 populations)(Figure
1) . In each of the population, a random sample from 7 to 17 individuals
was obtained. In each locality, individual samples were taken from
plants separated by at least 5 m (in order to avoid sampling clones) and
dried directly in silica gel for transport back to Jilin University for
subsequent DNA extraction.
Table 1. Summary of AFLP variation for 36 populations of