Abstract:
Cadmium (Cd), known as a non-essential heavy metal,
can cause oxidative stress in
plants. In this study, an attempt was carried out t
o find out whether Cd-induced oxidative
and microscopic changes could be observed in the ea
rly stage of seedling growth. Seeds of
Brassica napus
(cvs. Zheda 619 and ZS 758) were germinated
in vitro
at 0, 100, 200, 300,
and 500
μ
M Cd concentrations in dark for 48 hours. Results s
howed that the higher
concentration of Cd (500
μ
M) significantly reduced plant growth in both culti
vars.
However, Cd concentration in both cultivars increas
ed linearly with the Cd
concentration, but was more pronounced in ZS 758 th
an the other cultivar. Moreover, Cd
caused oxidative stress in germinated seeds by incr
easing reactive oxygen species,
however, no relationship was found between antioxid
ative defense capacity including
catalase, peroxidase, superoxide dismutase and glut
athione reductase activities and Cd
tolerance in the two cultivars. Cd toxicity showed
significant ultrastructural changes in
germinated seed cells, but cell structure in Zheda
619 did not show any difference, while
cell structure in ZS 758 was totally damaged under
higher concentration of Cd (500
μ
M).
Based on the present findings, it can be concluded
that cultivar Zheda 619 showed
comparatively higher tolerance and integrity of cel
l organelles under Cd stress.
Keywords:
Defense system, Malondialdehyde, Microscopic analy
sis, Oilseed rape,
Phytoremediation.
