The physiological responses of dimethyl sulfoxide
(DMSO) exposure were investigated in rice (
Oryza
sativa
L. cv. XZX 45) seedlings. The seedlings were
hydroponically exposed to different concentrations of
DMSO for 72 h. Results showed that a linear decrease in
relative growth rate and water use efficiency was observed
with rice seedlings with increasing DMSO concentrations.
The estimation of cell death measured by Evans blue
uptake also indicated DMSO-induced damage in root tissues.
Negligible decrease in chlorophylls was noted, while
significant reduction in carotenoids content was only
observed at 13.54 mM DMSO. Although DMSO did not
have any significant effect on protein content in roots, the
protein content in shoots was significantly decreased in a
dose-dependent manner. Proline content in both plant tissues
was positively affected by DMSO exposure,
responding an inverted U-shaped curve with DMSO concentrations.
Results also showed that DMSO-induced
accumulation of hydrogen peroxide (H
2O
2) was evident in
roots rather than shoots. DMSO did not result in any significant
changes in superoxide dismutase and peroxidase
activities as well as malondialdehyde content. Catalase
(CAT) activity in both roots and shoots was quite sensitive
to changes in DMSO treatments than other enzymes, suggesting
that CAT may play central role in the detoxification
of H
2O
2 in rice seedlings under DMSO exposure. Results
suggest that growth inhibition and cell death of rice
seedlings caused by DMSO exposure were largely related
to the accumulation of H
2O
2 in plant tissues.
