镉和铜的单一和互作效应对油菜的金属积累、亚细胞分布和化学形态的影响

发布时间：2018-04-06 03:31

本文选题：甘蓝型油菜　切入点：镉　出处：《浙江大学》2016年硕士论文

【摘要】：油菜(Brassica napus L.)是一种重要可食用油来源,并且拥有一定程度的抗金属等胁迫能力。因此发挥它在抗重金属胁迫上的潜力是很重要的。在不同的植物中研究不同的重金属元素的代谢机理,特别是对比不同的重金属特性(如镉和铜),也是很重要的。在这样的背景下,本试验试图通过镉和铜在甘蓝型油菜体内的富集方式、亚细胞的分布情况和化学形态来开展研究。此外,镉和铜互作的毒理学评估结果是两种重金属有可能在污染的土壤共存。鉴此,我们开展了本实验研究,取得的主要研究结果如下：(1)油菜幼苗在水培的条件下,在第五周进行不同程度的重金属处理(0、50、200μM),通过对重金属的积累情况来评价镉和铜的毒性作用。在整株植物中,镉的积累量高于铜。尽管铜的富集程度低,但造成了较高的氧化应激反应和较严重的生长抑制,叶绿素含量也下降更多。然而增加镉的浓度也可造成同样的毒害结果。同样浓度的两种金属都能影响水、矿物营养的吸收,但铜更不利于钾和锰的积累。相比浙双758,品种浙大622的生长抑制和氧化胁迫更明显,但是两个品种之间营养元素的改变程度却是相似的。结果还表明镉和铜对谷胱甘肽循环的影响不同,铜相比于逆境的含量高,而锌的活性还是镉逆境下高。通过对两种重金属共同处理下的积累和相关的毒害测定来探究铜和镉的互作效应,镉和铜相互影响其在植物体内的富集和毒害,镉和铜在油菜中的协同吸收造成了生长抑制,叶绿素损失和氧化的损伤。对敏感品种(浙大622)和抗性品种(浙双758)的比较中,我们发现存在协同作用。相比之下,重金属的协同作用对营养元素含量减少却是没有影响。然而,镉对铜的吸收的刺激效应只有在低浓度是有效的。与镉效应相反,铜对镉的吸收限制了镉的吸收。重金属的互作对矿质营养元素的影响较小。(2)在上述同样的条件下,通过重金属的亚细胞分布和化学形态探究镉和铜的特异性毒害。结果显示细胞壁和液泡中积累了最高比例的重金属。然而,与铜相比,镉在细胞壁上的残留少,部分解释了其较高的积累位置在可溶部分。尽管其较高的交换量,但是铜也显著地积累在可溶性部分,说明油菜植物细胞壁电荷密度低。尽管如此,抗性品种浙双758比敏感的浙大622在细胞壁上积累了更多的镉和铜；在可溶性部分的重金属浓度上没有基因型的差别存在。镉和铜在敏感的细胞器有不同的表现：镉在叶绿体和线粒体分布均匀,铜优先积累在叶绿体上,相应的在铜处理过的植物的叶绿体明显变化大。至于重金属的化学形态,镉和铜各自与不同细胞配体相互作用,说明存在不同的解毒途径；磷酸盐配体积极络合铜,但镉会以有机配体为主,使它们成为第二选择的配体。添加铜是由有机配体和草酸盐固定化,但后者不能够缓解镉的毒害。在重金属的毒性部分,镉的比例很大,以水萃取的形式存在,而铜更多以乙醇提取的形式存在。
[Abstract]:Rape (Brassica napus L.) is an important source of edible oil, and has a certain degree of resistance to metal stress ability. So it is very important to play in resistance to heavy metal stress on potential. Metabolic mechanism of heavy metal elements in different plants, especially comparing the different characteristics of heavy metals (e.g. cadmium and copper), is also very important. In this context, this experiment attempts to cadmium and copper in vivo enrichment of Brassica napus, subcellular distribution and chemical form to carry out the research. In addition, the toxicological evaluation of cadmium and copper is the result of the interaction of two kinds of heavy metals may coexist in pollution soil. In view of this, we carried out the experimental study, the main results are as follows: (1) rape seedlings in hydroponics under the condition of heavy metals in different degree in fifth weeks (0,50200 M), based on the money Toxicity accumulation belongs to the evaluation of cadmium and copper. In the whole plant, the amount of accumulation of cadmium was higher than that of copper. Although the enrichment degree of copper is low, but caused oxidative stress is higher and more severe inhibition of growth, chlorophyll content decreased more. However increased the concentration of cadmium can cause toxic results the same. Two kinds of metal of the same concentration can affect the water absorption of mineral nutrients, but copper is not conducive to the accumulation of potassium and manganese. Compared zheshuang 758 varieties, Zhejiang growth inhibition and oxidative stress in 622 is more obvious, but between the two kinds of nutrient elements change degree is similar. Results show that cadmium and copper have different effect on glutathione cycle, compared to the high content of copper and zinc stress, the activity of cadmium stress or high. According to the two kinds of heavy metal accumulation and treatment related toxicity determination to explore the interaction of copper and cadmium Effect of cadmium and copper in the interaction of plants enrichment and toxicity, cadmium and copper in rape in synergistic absorption caused growth inhibition, chlorophyll loss and oxidative damage. The sensitive cultivar (Zhejiang 622) and resistant cultivars (zheshuang 758) in the comparison, we found that the synergistic effect. Under the synergistic effect of heavy metals on nutrient content had no effect is reduced. However, the absorption of copper and cadmium on stimulation effect only at low concentration is effective. In contrast with the effect of cadmium, cadmium absorption limit of copper cadmium. The interaction has little effect on mineral nutrition of heavy metals (2). In the same conditions, the subcellular distribution and chemical forms of heavy metals on specific toxicity of cadmium and copper. The results showed that the cell wall in vacuole and accumulated the highest proportion of heavy metals. However, compared with copper, cadmium residue in the cell wall. Less, partly explains the position of its high accumulation in the soluble fraction. Despite its high exchange capacity, but also significantly accumulated in the soluble copper part, that the charge density rape plant cell wall is low. However, resistant cultivars zheshuang 758 than 622 Zhejiang sensitive on the cell wall accumulation of cadmium and copper more there is no genotype; heavy metal concentration in soluble part of the difference. Cadmium and copper have different performance in organelles: cadmium sensitive evenly in the chloroplast and mitochondrial distribution, copper preferentially accumulated in the chloroplast, the corresponding treatment in copper plant chloroplast changed obviously. As for the chemical speciation of heavy metals, cadmium and each cell with different copper ligand interactions, indicating the presence of detoxification in different ways; with extremely complex copper volume of phosphate, but the cadmium to organic ligands, so that they become the second ligand selection. Tim Copper addition is immobilized by organic ligands and oxalate, but the latter can not alleviate the toxicity of cadmium. In the toxic part of heavy metals, the proportion of cadmium is very large, and it exists in the form of water extraction, while copper exists more in the form of ethanol extraction.

【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X503.231

【相似文献】