Effects of exogenous melatonin on the morphology, photosynthetic
pigment, and reactive oxygen species parameters of rice seedlings under
NaCl stress
As
shown in Table 4, under NaCl stress, plant height (Figure 7), root
length, fresh weight, dry weight, chlorophyll a, chlorophyll b, and
total chlorophyll (chlorophyll a+b) content of seedlings were
significantly reduced compared to those of the control. Further, the
H2O2,
O2- ·, and MDA contents increased by
47.404%, 57.277%, and 36.815%, respectively.
Compared
with salt treatment alone,
exogenous melatonin at different concentrations (50-800
μmol·L-1) significantly increased plant height (Figure
7), root length, fresh weight, dry weight, chlorophyll a, chlorophyll b,
and total chlorophyll content (Table 4), whereas
H2O2,
O2-·, and significantly decreased MDA
content to different degrees. The higher the melatonin concentration,
the less obvious the alleviation effect under NaCl stress. These results
indicate that exogenous melatonin could increase the chlorophyll content
of rice seedlings under NaCl stress to a certain extent, enhance the
photosynthetic rate and biomass of leaves, reduce the ROS content in
seedlings, and promote the growth and development of seedlings.
TABLE 4 Effect of melatonin on the parameters of morphological,
photosynthetic, and reactive oxygen species of rice seedlings under NaCl
stress