Abstract:
Low temperature is a limiting factor
of
seed germination a
nd plant growth. In this
study, two independent experiments were conducted to investigate the effects of
l
ow
temperature on germination, early seedling growth and antioxidant systems in two
provenances
of
Elymus nutans
Griseb. (Damxung, DX and Gannan, GN).
The s
eeds and
early seedlings of DX were more tolerant
to low temperture
than those of GN. Low
temperature (5
o
C) negatively affected seed Germination Percentage (GP), Germination
Energy (GE) and the First Germination Time (FGT) in both
provenances
of
E. n
utans
.
Low temperature also increased Mortality Percentage (MP) when compared with control
plants grown at 25
o
C.
Low temperature treatments significantly reduced length and
fresh/dry weight of shoot
s
and root
s
in
the
two accessions after 29 d
ays
of exposur
e to 5
o
C.
In the second experiment, after 5 d
ays
of
l
ow temperature
treatment
, DX exhibited
significantly higher Chlorophyll (Chl)
and
Carotenoid (Car)
content
as well as
increased
activities of Peroxidase (POD), SuperOxide Dismutase (SOD), Catalase (CAT)
.
In
contrast we observed
lower Electrolyte Leakage (EL) and reduction of the amounts of
MalonDiAldehyde (MDA), Hydrogen peroxide (H
2
O
2
) and superoxide radical (
2
O
).
We
conclude that GN is more susceptible to
l
ow temperature than DX due
to more
severe
oxidative damage resulting from Reactive Oxygen Species (ROS) and lower
antioxidant
enzyme activities
.
Keywords
:
Antioxidant systems
,
E
arly seedling growth
,
Elymus nutans
Griseb.
,
G
ermination,
Low temperature
.
