重金属Pb(Ⅱ)对萝卜种子萌发及幼苗生长的影响

Effects of Pb(Ⅱ) on Seed Germination and Seeding Growth of Radish

探讨重金属Pb(Ⅱ)对萝卜生长的影响,为农产品无公害化研究提供理论依据。研究不同浓度(0、50、150、300、600、800、1000mg/L)Pb(Ⅱ)处理对萝卜种子萌发和幼苗生长的影响。(1)当Pb(Ⅱ)浓度为50mg/L时,萝卜种子的发芽率、发芽势、发芽指数和活力指数与对照相比差异不显著。Pb(Ⅱ)浓度为150mg/L时,萝卜种子的发芽势和活力指数与对照相比差异不显著,而发芽率和发芽指数与对照相比呈显著差异。当Pb(Ⅱ)浓度大于300mg/L时,各项萌发指标均与对照呈极显著差异。(2)低浓度(50、150mg/L)的Pb(Ⅱ)处理对萝卜幼苗根长和芽长有抑制作用,随着Pb(Ⅱ)浓度的升高,抑制程度增加,但对根的抑制大于对芽的抑制。(3)在Pb(Ⅱ)的胁迫下,萝卜叶片叶绿素a和叶绿素b的含量均下降,叶绿素a比叶绿素b更为敏感。(4)Pb(Ⅱ)浓度为50mg/L时,SOD活性达到峰值,然后随着Pb(Ⅱ)浓度的增加活性减小,POD活性随着Pb(Ⅱ)浓度的增加而增加。萝卜对重金属Pb(Ⅱ)污染比较敏感。

Effects of Pb （Ⅱ） on seed germination and seeding growth of radish were studied, in order to provide theoretical basis for non polluted agriculture product. The experiments researched the effects on seed germination and seedling growth of radish with Pb （Ⅱ） treatments （0,50,150,300,600,800,1 000 mg/L）. The results indicated that： （1） The effects of Pb（Ⅱ） on the germination percentage, germination energy, germination index and vigor index of radish seeds were not significant （p 〉 0.05 ） when Pb（Ⅱ） concentration was 50 mg/L. The germination energy and vigor index were not significant（ p 〉 0.05 ）, but the germination percentage and germination index were significant （ p 〈 0.05 ）, when the concentration of Pb （Ⅱ） was 150 mg/L. Once the Pb（Ⅱ） concentrations were higher than 300 mg/L, each index of germination were significandy different from control（p 〈0.01 ）. （2）The low concentrations Pb（Ⅱ） （50,150 mg/L） had already inhibited root and bud growth of radish seedling. As the concentration increasing, the inhibition became more and more heavily, and the effect on root was stronger. （3） Under Pb （Ⅱ） treatments of different concentra- tions, the content of chlorophyll a and b of radish cotyledon decreased, but chlorophyll a was more sensitive than chlorophyll b. （4）The activity of SOD was up to the highest point at 50 mg/L of Pb（Ⅱ） concentration and decreased afterwards. With the concentration increasing, the activity of POD increased. The radish seedlings were more sensitive to Pb （Ⅱ） treatments.