几种重金属离子对小白菜种子萌发及生理活性的影响

本试验研究了镍(Ni^2 )、镉(Cd^2 )、铜(Cu^2 )、锌(Zn^2 )、铬(Cr^3 )、银(Ag^ )、铅(Pb^2 )7种重金属离子对小白菜种子萌发和萌动种子细胞膜透性的影响。结果表明，0．5、5mg／L浓度下Zn^2 、Ag^ 、Pb^2 略促进萌发，Cu^2 在50mg／L浓度下极显著地抑制萌发，500mg／L浓度下各离子均显著抑制萌发。0．5mg／L低浓度处理时，Zn^23 和Ni^2 促进小白菜幼芽伸长。随浓度增加，重金属离子均引起小白菜细胞膜透性逐渐增加，但幼芽长度降低。发芽率与细胞膜透性间存在一定的相关关系。综合考虑，Zn^2 对小白菜种子萌发毒性相对较小，Cr^3 毒害最大，Cu^2 毒害仅次于Cr^3 ，500mg／L处理浓度下以Ag^ 毒害最大。

Effects of Heavy Metal Ions on Germination and Physiological Activity of Brassica campestris ssp. chinensis L. Seeds

Pakchoi (Brassica campestris ssp. chinensis L. ) seeds were treated with different heavy metals ions, including Ag~ + ,Ni~ 2+,Cd~ 2+, Cu~ 2+,Zn~ 2+,Pb~ 2+ and Cr~ 3+ to study the effects of different heavy metal ions and concentrations ( 0.5,500 mg/L~ ) on germination and membrane permeability. The results showed that the germination of pakchoi seeds slightly promoted by 0.5 and 5 mg/L of Zn~ 2+, Ag~ + and Pb~ 2+. 5 mg/L of~ Cu~ 2+ had significantly inhibitory effect. All heavy metal ions significantly inhibited the seed germination at 500 mg/L~ level. At 0.5 mg/L~ level, Ni~ 2+ and Zn~ 2+ increased Pakchoi shoot length. With increasing concentrations, membrane permeability was increased by every heavy metal ion, but the shoot length was decreased. The toxicity of Zn~ 2+ to germination of Pakchoi seeds was relatively less,that of Cr~ 3+ was the highest, and Cu~ 2+ just after Cr~ 3+. In the highest level (500 mg/L), the toxicity of Ag~ + was the highest in all tested heavy metal ions.