【作者】 王海青；

【导师】 段毅豪；

【作者基本信息】 山西大学 ， 环境科学， 2014， 硕士

【摘要】 本论文研究了重金属铅(Pb)、锌(Zn)、汞(Hg)对莜麦(Avena nuda)的毒性作用。本研究把莜麦种子暴露于不同浓度梯度的铅、锌、汞染毒液中,进行水培实验。测定莜麦的种子的发芽率、植株高度、根的长度、叶绿素-(a,b)、丙二醛、可溶性糖、根系活力以及重金属在植物体中的积累情况,得到如下结果。pb2+暴露浓度低于15mg/L时,对莜麦的种子发芽率、植株高度和主根长度有一定的促进作用,pb2+为15～30mg/L时,则表现为抑制作用,并且随着暴露浓度的增大,生长抑制作用随之增大。pb2+暴露浓度在0～30mg/L范围内,随着pb2+暴露浓度的升高,莜麦中叶绿素a的含量呈现先升高再降低的趋势,pb2+浓度临界值为15mg/L,而莜麦中的叶绿素b的含量和叶绿素总含量均呈现逐渐降低的趋势,并且叶绿素b的变化趋势比叶绿素a快。pb2+浓度在0～30mg/L范围内,莜麦的根系活力值则随pb2+浓度上升而下降,但丙二醛、可溶性糖的和莜麦中铅离子的含量随之升高。莜麦呈现出一定程度的铅离子耐受性和富集能力。二次曲线拟合表明pb2+暴露浓度和叶绿素、丙二醛含量、可溶性糖含量、根系活力和铅元素富集量呈现较好的拟合度。Zn2+暴露浓度低于50mg/L时,对莜麦的种子发芽率、植株高度和主根长度均表现出促进作用；在50～100mg/L时则呈现出轻微抑制作用。Zn2+在0～100mg/L范围内,可溶性糖和叶绿素a都呈现先升高再降低的趋势,临界浓度均为50mg/L,叶绿素b呈现逐渐降低趋势,且Zn2+对叶绿素a抑制作用高于叶绿素b。Zn2+在0～100mg/L范围内,随着Zn2+暴露浓度的升高,丙二醛的含量和根系活力均呈现上升趋势,植物体内锌积累增长,增长幅度在Zn2+暴露浓度大于50mg/L后逐渐平缓。Zn2+暴露浓度低于50mg/L时,莜麦对Zn2+暴露的耐受性和富集能力较强。二次曲线拟合表明Zn2+暴露浓度和叶绿素、丙二醛含量、可溶性糖含量、根系活力和铜元素富集量呈现较好的拟合度。Hg2+暴露浓度低于1.0mg/L时,对莜麦的种子发芽率植株高度和主根长度的影响不大。Hg2+暴露浓度为1.0～5.0mg/L时,则会产生明显的抑制作用。在0～5.0mg/L范围内,Hg2+浓度与根系活力和叶绿素均呈负相关,叶绿素b比叶绿素a含量下降更为明显。在0～5.0mg/L范围内,随着Hg2+暴露浓度的升高,丙二醛和可溶性糖的升高,植物体内汞积累增长。Hg2+富集在暴露浓度大于2.0mg/L后开始变的相对平缓。莜麦对低浓度的Hg2+(<1.0mg/L)有一定的耐受性和富集作用。二次曲线拟合表明Hg2+暴露浓度和叶绿素、丙二醛含量、可溶性糖含量、根系活力和汞元素富集量呈现较好的拟合度。本课题研究结果为山西省重金属污染土壤的植物修复提供了基础数据,为莜麦作为山西省受重金属污染土壤修复的先锋植物提供了一定的数据支持。更多还原

【Abstract】 This thesis examined the toxicological impact of metals lead, zinc and mercury on naked oat (Avena nuda). The seeds were exposed to the Pb2+, Zn2+ or Hg2+ solution and the seedlings were collected for testing 8 indicators including the germination rate, seedling height, main root length, chlorophyll-(a,b), malondialdehyde, soluble saccharide, root activity and metal accumulation. The results are summarized as follows.The Pb2+ at concentration less than 15mg/L stimulated the germination rate, seedling height and main root length. When the Pb2+ concentration was more than 15mg/L the heavy metal increasing inhibited the three growth indicators in gradients. In the Pb2+ exposures at 0-30mg/L the chlorophyll-a level increased and then decreased at the turning point of Pb2+ at 15 mg/L. In contrast the chlorophyll-b kept declining even at the low Pb2+ exposure. The decreasing slope of chlorophyll-b was steeper than that of chlorophyll-a. In the range of Pb2+ at 0-30mg/L the exposure concentration were negatively correlated to root activity, but the positively correlated to the malondialdehyde and soluble saccharide content. Naked oat demonstrated resistance and bioaccumulation to lead exposure. The quadratic curve fitting showed satisfactory goodness-of-fit of Pb2+ exposure concentration verses the indicators of chlorophyll, malondialdehyde, soluble saccharide, root activity and lead accumulation.The Zn2+ at concentration of less than 50mg/L stimulated the seed germination, seedling height and main root length, but the impact turned slightly inhibitive at 50-100mg/L. In Zn2+ exposure of 0～100mg/L the soluble saccharide and chlorophyll-a first increased and then decreased at the turning point of 50mg/L, while the chlorophyll-a kept decreasing. The Zn2+ inhibited chlorophyll-a more than chlorophyll-b. In the same exposure range the increasing Zn2+ concentration corresponded to the increased malondialdehyde level, root activity, and Zn2+ bioaccumulation. The Zn2+ accumulation became gradually stable when the Zn2+ exposure were higher than 50mg/L, below which the naked oat demonstrative satisfactory resistance and accumulation. The quadratic curve fitting showed satisfactory goodness-of-fit between Zn2+ exposure concentration and the indicators of chlorophyll, malondialdehyde, soluble saccharide, root activity and copper accumulation.The Hg2+ showed no significant effects on germination, seedling height and main root length of naked oat when Hg2+ exposure was at less than 1.0mg/L, beyond which significant inhibition was observed. In Hg2+ exposure of 0-5.0mg/L the Hg2+ concentration were negatively correlated to root activity and chlorophyll-(a,b), and decline of chlorophyll-b was steeper than chlorophyll-a. In the same exposure range the increasing Hg2+ concentration corresponded to the increased malondialdehyde level, root activity, and Hg2+ bioaccumulation. The Hg2+accumulation became gradually stable when the Hg2+ exposure were higher than 2.0mg/L. The naked oat showed certain resistance and bioaccumulation to low Hg2+ exposure (<1.0mg/L)..The quadratic curve fitting showed satisfactory goodness-of-fit of Hg2+ exposure concentration verses the indicators of chlorophyll, malondialdehyde, soluble saccharide, root activity and mercury accumulation.This thesis provided basic data on the metal toxicology of naked oat which is commonly cultivated in the Loess Plateau, which might be useful in selecting the crop species for soil remediation in the region.更多还原