Abstract:

In order to investigate the germination characteristics of adzuki bean seeds under heavy metal stress (Cu ²⁺, Zn ²⁺, Cr ⁶⁺) and the accumulation in seedlings, the germination index of adzuki bean seeds was studied under different concentrations of heavy metal stress (5, 10, 50, 100, 200, 300, 400mg/L) based the material of "Jinxiaodou No.6".And the accumulation of different heavy metals in the roots, stems and leaves of the bean seedlings was measured. The results showed that: when Cu ²⁺ stress concentration was 5, 300 or 400mg/L, the germination potential of adzuki bean was higher than that of the control, which was opposite to that of under the same concentration of Zn ²⁺ and Cr ⁶⁺ stresses. The three heavy metals had the similar effects on germination rate of adzuki bean at different concentrations. While the stress concentration was 50mg/L, the root length of adzuki bean seedlings was significantly longer than that of the control. While Cu ²⁺ concentration was 200-400mg/L, it was observed that the hypocotyl length was shorter than that of the control. As the concentration was 5-400mg/L of Zn ²⁺ and Cr ⁶⁺, the growing of hypocotyls of adzuki bean was risen first and then fallen, and the hypocotyl was the longest at the concentration of 100mg/L. The accumulation of heavy metal Cu ²⁺ was higher in adzuki bean seedlings, followed by Cr ⁶⁺ and Zn ²⁺, which mainly enriched in the roots, and partly in the stems and leaves. The suitable concentration of heavy metals can promote the germination of adzuki bean seeds, and the roots can absorb heavy metals well. Planting adzuki beans can make the soil environment better.

Key words: Adzuki bean, Heavy metal stress, Seed germination, Accumulation