Fig 1.
Germination of seeds with different concentrations of PEG.
0: deionized water, no water stress; 3%, 6%, 9% and 12% were indicated 3%, 6%, 9% and 12% PEG6000 (w/v).
Fig 2.
Effect of soaking with melatonin on H2O2 (A) contents and O2·− (B) production rate of soybean radicle under PEG stress.
0%, 3% and 6% were indicated 0%, 3% and 6% PEG6000 (w/v). Values are the means of three replicates ± S.E. Bars with different letters are significantly different at P≤0.05.
Fig 3.
H2O2 and O2·− staining of soybean radicle root tips under different treatments.
H2O2 on the left and O2·− on the right. The horizontal axis is PEG concentration, the vertical axis is melatonin concentration, and the scale length is 500 μm.
Fig 4.
ROS staining of soybean radicle tips on different treatments.
The horizontal axis is PEG concentration, the vertical axis is melatonin concentration, and the scale length is 500 μm.
Fig 5.
Transmission electron micrographs of ultrathin sections of cells from root tips treated with different treatments.
The horizontal axis is PEG concentration, the vertical axis is melatonin concentration, the scale length is 2 μm, 2000 times magnified.
Fig 6.
Effect of soaking with melatonin on EL (A) and MDA (B) of soybean radicle under PEG stress.
0%, 3% and 6% were indicated 0%, 3% and 6% PEG6000 (w/v). Values are the means of three replicates ± S.E. Bars with different letters are significantly different at P≤0.05.
Fig 7.
Effect of soaking with melatonin on antioxidant enzyme activity of soybean radicle under water stress caused by PEG.
0%, 3% and 6% were indicated 0%, 3% and 6% PEG6000 (w/v). Values are the means of three replicates ± S.E. Bars with different letters are significantly different at P≤0.05.
Fig 8.
Effect of soaking with melatonin on soluble protein (A) and proline (B) of soybean radicle under PEG stress.
0%, 3% and 6% were indicated 0%, 3% and 6% PEG6000 (w/v). Values are the means of three replicates ± S.E. Bars with different letters are significantly different at P≤0.05.
Fig 9.
Analysis of all indicators of soybean seeds based on GGE biplot under different treatments.
Table 1.
Effect of soaking with melatonin on germination of soybean seeds under PEG stress.
Table 2.
Effect of soaking with melatonin on radicle shape and biomass of soybean seeds under PEG stress.