铁、磷营养降低植物Cd积累的机制

发布时间：2018-01-04 20:40

本文关键词：铁、磷营养降低植物Cd积累的机制　出处：《浙江大学》2017年硕士论文　论文类型：学位论文

更多相关文章： 拮抗作用 镉竞争 重金属 铁磷 IRT1

【摘要】：土壤镉污染问题已经成为威胁粮食产量和品质最为严重的问题之一。因此,探索有效的技术或方法阻控镉通过植物进入食物链迫在眉睫。其中,通过养分调控的农艺管理措施阻控植物镉吸收是一种绿色、经济、环保的策略。大量研究发现Fe、P营养供应与铁的吸收系统I]RT1密切相关,而且IRT1又是植物吸收镉离子的关键途径之一。本文以野生型拟南芥Co1-0及以该生态型为背景的铁吸收功能缺失突变体irt1-1、irt1-2为研究材料,研究了 Fe、P营养供应对植物镉吸收和积累的影响及其机制。主要研究结果如下:1.采用营养液培养的方法,研究了镉胁迫状况下,野生型拟南芥生长状况的变化。结果表明,镉胁迫导致野生型拟南芥叶片出现了失绿黄化、叶柄坏死枯萎,生长受阻的症状。当在营养液中外源供铁时或缺磷时,野生型拟南芥中的上述镉胁迫症状得到显著减轻,同时拟南芥体内镉的含量也显著降低。这表明,增加供铁或缺磷可通过减少拟南芥对镉的积累缓解镉的毒害胁迫。2.采取植物组织染色的方法,研究了镉胁迫下野生型拟南芥根尖活性氧(ROS)和细胞膜完整性的变化。结果表明,植物根尖ROS含量显著增加,细胞膜受损严重。当增加外源供铁时,根尖ROS和Evans blue染色程度显著降低;缺磷时,显著降低了根尖ROS的积累。可见,增加供铁或缺磷减轻了镉对根系造成的氧化损伤,从而增强了拟南芥植株对镉毒的耐性。3.通过实时定量PCR分析,研究了镉胁迫下,增加供铁Fe或缺P对二价铁转运体1RT1基因表达的调控作用。结果显示,增加供铁时,植物根系中IRT1的基因表达水平显著下降。同时,拟南芥对镉的吸收明显受到抑制。缺磷时,虽然IRT1的基因表达量反而上升,但是拟南芥对镉的吸收同样明显受到抑制。可见,增加供铁可通过降低IRT1的表达水平,降低植物根系对镉的吸收,达到缓解镉毒害的效果。而缺磷却可能是通过非IIRT1途径减少植物对镉的吸收,缓解榻毒。4.采用Fe-Cd间隔、共存循环处理和P-Cd间隔循环处理的实验方法,研究了镉胁迫下,增加供铁或缺磷对拟南芥镉吸收的影响。结果表明,增加供铁或缺磷均减少了植物对镉的吸收和积累。基于循环处理,我们发现增加外源供铁还可以通过增强Fe、Cd吸收间的竞争作用降低植物根系对镉的吸收。进一步验证了缺磷减少植物对镉的吸收是通过非IRT1途径实现的,该过程与P-Cd之间的拮抗作用无关。
[Abstract]:The problem of soil cadmium pollution has become one of the most serious problems on the yield and quality of food threat. Therefore, to explore the effective method of preventing and controlling technology or cadmium enters into the food chain through plant is imminent. Among them, the agronomic management measures of nutrient regulation resistance controlled plant cadmium absorption is a kind of green economy, environmental protection, the study found a large number of strategies. Fe, P and iron nutrition supply is closely related to the absorption of I]RT1 and IRT1 system, and is one of the key ways of plant uptake of cadmium ion. The wild type Arabidopsis Co1-0 and the ecological background of the iron absorption function of mutant irt1-1, irt1-2 as the study material, study the effect of P Fe, the absorption and accumulation of nutrient supply cadmium and its mechanism. The main results are as follows: 1. using the method of nutrient solution culture, the effects of Cd stress conditions, changes in wild type Arabidopsis growth conditions. The results show that, Cadmium stress leads to wild type Arabidopsis leaves appeared chlorosis, necrotic petiole wither, the growth of symptoms. When in nutrient solution for exogenous iron or phosphorus deficiency, the wild type Arabidopsis cadmium stress symptoms was significantly reduced, the cadmium content of Arabidopsis thaliana was significantly lower at the same time. This shows that the increase of iron supply or phosphorus can reduce the accumulation of cadmium in Arabidopsis alleviated the toxicity of Cd stress.2. take the method of plant tissue staining, under cadmium stress were studied in wild type Arabidopsis root active oxygen (ROS) and the integrity of the cell membrane. The results show that the content of ROS in plant roots increased significantly, cell membrane increased when severely damaged. Exogenous iron supply, ROS and Evans blue apical staining degree was significantly decreased; P, significantly reduced the root ROS accumulation. The increase for iron or phosphorus reduces oxidative damage caused by cadmium on root, thus increasing .3. strong tolerance to cadmium toxicity in Arabidopsis by real-time quantitative PCR analysis, studied under cadmium stress, increased regulation of iron Fe or lack of P expression in two valent iron transporter 1RT1 gene. The results showed that the increased iron supply, IRT1 in plant roots gene expression level was significantly decreased. At the same time, the absorption of Arabidopsis thaliana the CD was significantly inhibited. Phosphorus deficiency, while the expression of IRT1 increased, but the absorption of cadmium in Arabidopsis also significantly inhibited. Obviously, increased iron supply through reducing the expression level of IRT1, reduce the absorption of cadmium in plant roots, to alleviate Cd toxicity and P deficiency may result. Is to reduce the uptake of cadmium by non IIRT1 pathway, alleviate the virus.4. by Fe-Cd bed interval, and P-Cd interval coexistence cycle treatment cycle treatment experimental method, studied under cadmium stress, increase the supply of iron or phosphorus deficiency on Arabidopsis cadmium absorption The effect. The results show that the increase for iron or phosphorus were reduced by plant uptake and accumulation of cadmium. Based on the cycle of treatment, we found that the increase of exogenous iron can also enhance Fe, competition between Cd absorption and reduce the absorption of plant roots on cadmium. Further validation of the phosphorus reduction in Cd uptake less the plant is achieved by non IRT1 pathway, independent of antagonism between the process and the P-Cd.

【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X173;X53

【相似文献】