【作者】 孙华；

【导师】 白瑞琴；

【作者基本信息】 内蒙古农业大学 ， 果树学， 2008， 硕士

【摘要】 本试验采用水培的方法,以园林地被植物甘野菊为材料,系统研究了Cd、Pb胁迫对甘野菊种子萌发、植株生长、生理生化的影响。本研究为阐明植物重金属毒害机理提供了依据,为园林地被植物进行矿冶区、土壤污染地植被恢复和重金属的植物修复提供了参考。试验得出的主要结果如下:1.种子萌发试验表明:当浓度低于20mg/L时,Cd对甘野菊种子的发芽率、发芽势、发芽指数均没有显著影响。在0-100mg/L范围内随着处理浓度的升高,甘野菊活力指数显著降低,幼苗长度减小,说明低浓度Cd胁迫(0mg/L、20mg/L)对甘野菊种子萌发的影响较小,但高浓度Cd胁迫(50mg/L、100mg/L)对甘野菊种子萌发的影响显著,幼苗几乎不伸长,也无侧根,褐变加重。萌发后幼苗的建成对Cd胁迫反应敏感。Pb胁迫对甘野菊种子的发芽率、发芽指数没有明显的影响,但发芽势、活力指数显著降低,幼苗长度减小,严重时幼苗变褐、死亡,抑制作用增强。2.植株生长发育研究发现:Cd、Pb胁迫下,甘野菊幼苗的植株生长缓慢,叶片发黄甚至出现干枯落叶现象,根系变褐、变黑。老叶症状较新叶严重。Cd、Pb胁迫能明显抑制甘野菊的生长:甘野菊根系总长度、根表面积、地上部干重、根系干重、叶绿素含量等均随着重金属胁迫的加重显著下降,说明Cd、Pb胁迫对甘野菊的毒害加重。但总体上看,Cd对甘野菊的毒害作用强于Pb。3.生理生化试验证明:甘野菊在Cd、Pb胁迫后SOD活性、MDA含量、Pro含量都随着处理浓度的加大而增加;POD在低浓度Cd(1mg/L)胁迫下,活性急剧增强,在Pb胁迫下,处理与对照的活性无显著差异;低浓度Cd(1mg/L)和Pb(5mg/L)胁迫后均导致可溶性糖含量的增加,表明甘野菊对镉、铅胁迫在一定的浓度范围内有抵抗能力,但随处理浓度的加大,抗性能力减弱。更多还原

【Abstract】 The systematic studies had been done with respect to the mechanisms of Cd, Pb accumulation and toxicity in Dendranthema lavandulifolium by hydroponic culture, based on the investigation of Cd, Pb on the seed germination, plant growth, physiological metabolisms in Dendranthema lavandulifolium. This study provided the theoretical background for both heavy metal toxicity mechanisms and plant resistance to heavy metal, and practical background for the phytoremediation at mining sites or contaminated soils.The main results are as follows:1. The experiments were conducted to evaluate the effects of different cadmium, lead levels on the seed germination aspects of Dendranthema lavandulifolium. The results showed that Cd had no effect on Dendranthema lavandulifolium germination rate,germination vigor,germination index when Cd concentration at 20 mg.L-1, but its vigor index and seedling length reduce with the increment of Cd concentration at 0 mg.L-1 and 100mg.L-1.Pb concentration had no effect on Dendranthema lavandulifolium germination rate,germination index,but Pb inhibitory function was enhanced in the germination vigor, vigor index and seedling length with the increment of exposure concentration. Even brown or dead seedling could be observed.2. The growth of Dendranthema lavandulifolium to the stress of Cd and Pb at different concentrations were studied by hydroponic culture. It is found that plant growth can be inhibited by Cd and Pb stress. Total root length, root surface area, root dry weight, chlorophyll contents reduce significantly with the increment of heavy metal stress, thereby Cd and Pb are more toxic to Dendranthema lavandulifolium. Cd and Pb toxicity symptoms, like slow growth, chlorisis leaves, brown roots were observed. Stronger toxicity symptoms appeare on older leaves.Taking one with another, Cd is more toxic than Pb .3. The Physiological and biochemical changes of Dendranthema lavandulifolium to the stress of Cd and Pb at different concentrations had been measured. The results show that SOD activity, MDA content,Pro content increase as Cd and Pb concentration increase. POD activity increase at 1mg.L-1 Cd , but Pb do not show significant effect on Dendranthema lavandulifolium. Both Cd(1 mg.L-1)and Pb(5 mg.L-1)stress result in the increment of soluble sugar content. It can be concluded that Dendranthema lavandulifolium is resistant to Cd and Pb stress at low concentration, while is reduce to Cd and Pb stress at high concentration.更多还原