Figure 3.

Melatonin promoted the primary root elongation and alleviated the toxicity of cadmium to the root growth on the wheat seedlings. (A) Effect of different concentrations of melatonin on the seed germination at 24 h after seed priming (n = 4). (B) Primary root length at 2 d after root treatment with different concentrations of melatonin (n = 20). (C,D) Root growth of the germinated seedlings at 24 h after cadmium (0.2 mM), or cadmium + melatonin treatment (n = 20). (E,F) Primary root length and adventitious root number were calculated three days after treatment (n = 20). Values are mean ± SE. Means with different letters (a, b and c) are significantly different at p < 0.05 using Tukey’s test. Significance between treatment and control was determined by Student’s t test. Significance level: ** p < 0.01. NS, no significance.