Seed germination responses of a mountain medicinal herb Aconitum spicatum to different environmental conditions
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Department of Botany
Abstract
Germination studies of medicinally important mountain plants under different
environmental conditions is potentially important to understand the impacts of climate
and other environmental changes. Seeds from different populations of a species along
the elevation gradient may respond in different directions and intensity to the changing
environmental conditions. In this study, seed germination patterns of a mountain
medicinal herb Aconitum spicatum were analyzed to understand variation under
environmental gradients. Seeds of Aconitum spicatum collected from three different
elevations (sub alpine to alpine) were germinated in growth chamber under different
temperatures (low: 25/15°C; high: 30/20°C), light environment (12h photoperiod and
complete dark, white and far-red light) and water potentials (−0.1, −0.25, −0.5, −0.75,
−1MPa). Freshly collected as well as the seeds stored for one year were used in the
germination experiments. Seed mass, Germination percentage (GP), Mean germination
time (MGT) and Timson’s index (TI) were calculated. The result showed that seeds
from low elevation comparatively had higher seed mass and germination than high and
mid elevation. At low temperature, seeds had higher GP and TI than in high temperature
while MGT was longer in high temperature. With increasing level of water stress,
germination decreased. Germination was highest in white fluorescent light than far-red
light. Seed germination percentage and the Timson’s index increased after long
duration of cold storage (73 weeks). The results of this study advance our knowledge
and comprehension of the potential effects of climate change on alpine plants. This
study found that there wasn't always a consistent pattern associated to elevation and
that germination responses varied greatly among elevational provenances. Another
important conclusion of the current study is that it may not be enough to characterize a
species' germination response by examining only one population since, as it showed,
local environmental conditions may have an effect on seeds.