本文選題：鎘 + 植物修復(fù)��； 參考：《西南大學(xué)》2017年碩士論文

【摘要】：近年來(lái),隨著城市化、工業(yè)化和農(nóng)業(yè)化的集約發(fā)展,規(guī)模的不斷擴(kuò)大,工業(yè)“三廢”排放、化肥農(nóng)藥濫用、污水灌溉及城鎮(zhèn)污泥的使用等,使得土壤鎘含量日益增加,土壤鎘污染問(wèn)題日趨嚴(yán)重。如何治理和修復(fù)土壤鎘污染備受關(guān)注。植物修復(fù)技術(shù)作為一種新興的綠色生物技術(shù),具有操作簡(jiǎn)單、經(jīng)濟(jì)及技術(shù)上能夠大面積實(shí)施等優(yōu)點(diǎn),被認(rèn)為是修復(fù)重金屬污染土壤的最佳選擇。黑麥草(Lolium multiflorum L.)一年生或短期多年生,生物量大,對(duì)土壤重金屬有極強(qiáng)的富集作用,同時(shí)生長(zhǎng)迅速、分蘗能力強(qiáng),可以快速覆蓋地面;印度芥菜(Brassica juncea L.)為十字花科蕓薹屬植物,其生長(zhǎng)周期短、地上部生物量大、可富集多種重金屬,在植物修復(fù)中有較大的應(yīng)用潛力;紫花苜蓿(Medicago Sativa L.)為豆科多年生草本植物,是一種高產(chǎn)出的經(jīng)濟(jì)作物,其對(duì)Cd離子也具有較高的富集作用。目前有關(guān)黑麥草、紫花苜蓿及印度芥菜對(duì)鎘吸收能力的比較以及相關(guān)植物耐鎘基因等分子機(jī)理層面的研究較少。因此,本試驗(yàn)以黑麥草(品種為邦德和阿伯德)、印度芥菜及紫花苜蓿為試驗(yàn)材料,通過(guò)土培試驗(yàn)?zāi)M礦區(qū)土壤Cd污染水平(0、75、150、300及600 mg·kg~(-1)),研究不同鎘富集植物在不同鎘污染水平土壤上生長(zhǎng)、抗氧化酶活性、Cd含量及積累量的差異,探求不同植物的最大Cd吸收值,以及通過(guò)RT-PCR觀察鎘抗性基因表達(dá)情況,從分子機(jī)理層面解釋植株富集重金屬機(jī)制,以期為土壤Cd污染的合理防治和修復(fù)提供理論依據(jù)。主要研究結(jié)果如下:(1)黑麥草(邦德和阿伯德)地上部干重及植株總干重隨土壤鎘污染水平的增加表現(xiàn)為先增加后減少趨勢(shì)。75 mg·kg~(-1)Cd、150 mg·kg~(-1)Cd分別刺激了黑麥草(邦德)、黑麥草(阿伯德)生長(zhǎng),其地上部干重較對(duì)照分別增加10.06%和25.84%。各鎘處理下,黑麥草(邦德和阿伯德)地上部干重遠(yuǎn)高于印度芥菜和紫花苜蓿。(2)在不同鎘污染水平下,3種鎘富集植物光合系統(tǒng)參數(shù)均受到顯著抑制。隨土壤鎘水平增加,3種鎘富集的MDA含量呈下降趨勢(shì),當(dāng)外源鎘水平為600 mg·kg~(-1)時(shí),黑麥草(邦德和阿伯德)、紫花苜蓿及印度芥菜根系MDA含量均顯著低于對(duì)照(P0.05),分別較對(duì)照降低了49.62%、44.44%、40.74%及51.68%。隨鎘脅迫增加,SOD、POD總體呈先升高后降低的趨勢(shì),CAT則呈降低趨勢(shì)。(3)黑麥草(邦德和阿伯德)、紫花苜蓿及印度芥菜對(duì)鎘均具有較強(qiáng)的富集能力,各部位鎘含量均為根系地上部。且在150 mg·kg~(-1)、75 mg·kg~(-1)Cd水平下,黑麥草(邦德和阿伯德)、紫花苜蓿和印度芥菜地上部鎘含量分別為171.827 mg·kg~(-1)和169.122 mg·kg~(-1)、356.463 mg·kg~(-1)和308.735 mg·kg~(-1),均超過(guò)超富集植物臨界值(100 mg·kg~(-1)),表現(xiàn)出極強(qiáng)的超富集潛力。(4)在75 mg·kg~(-1)Cd時(shí)以黑麥草(阿伯德)的土壤鎘去除率最佳,為16.24%,其他鎘水平下,均以紫花苜蓿對(duì)土壤鎘去除率最佳,分別為19.82%、30.72%和26.78%。綜合考慮積累量及土壤鎘去除率等因素,可以采用多種植物輪作方式提高土壤Cd的整體去除率。(5)在各Cd污染水平下,土壤鎘均主要以EXC-Cd存在,FDC高達(dá)55.09%~83.23%。各形態(tài)Cd FDC大小順序?yàn)?EXC-CdCAB-CdFeMn-CdRES-CdOM-Cd。隨著土壤鎘水平的增加,EXC-Cd的FDC不斷增加。土壤各鎘形態(tài)中,除OM-Cd外,其余土壤鎘形態(tài)與植株地上及根系鎘含量均呈極顯著正相關(guān)(P0.01)。(6)供試3種植物材料,黑麥草(品種為邦德和阿伯德)、紫花苜蓿及印度芥菜的BCF均大于1,且印度芥菜紫花苜蓿黑麥草(阿伯德)黑麥草(邦德),印度芥菜對(duì)鎘的富集能力最強(qiáng)。所有處理TF值均小于1,大小順序?yàn)楹邴湶?阿伯德)黑麥草(邦德)紫花苜蓿印度芥菜,黑麥草(阿伯德)能最有效聚集土壤中的鎘。(7)外源鎘誘導(dǎo)黑麥草(邦德和阿伯德)2個(gè)鎘代謝相關(guān)的基因(家族)OAS和IRT表達(dá)水平在不同鎘水平間的變化趨勢(shì)差異顯著;相同物種不同亞種間也存在很大差異。黑麥草(邦德)OAS和IRT基因(家族)表達(dá)對(duì)鎘處理較敏感,在75 mg·kg~(-1)Cd時(shí)即出現(xiàn)顯著上調(diào);黑麥草(阿伯德)OAS和IRT基因(家族)總體在150 mg·kg~(-1)鎘水平時(shí)出現(xiàn)顯著上調(diào),且上調(diào)幅度均顯著低于黑麥草(邦德)。同一家族內(nèi)部的不同成員基因在同一植株的反應(yīng)趨勢(shì)相同。
[Abstract]:In recent years, with the intensive development of urbanization, industrialization and agriculture, the expansion of the scale, the emission of industrial "three wastes", the abuse of chemical fertilizers and pesticides, the irrigation of sewage and the use of municipal sludge, the cadmium content in soil is increasing, and the problem of soil cadmium pollution is becoming more and more serious. As a new green biological technology, it has the advantages of simple operation and large area implementation in economy and technology. It is considered to be the best choice for remediation of heavy metal contaminated soil. Lolium multiflorum L. (ryegrass) is an annual or short term perennial with a large biomass, strong enrichment to heavy metals in soil and growth of heavy metals. India mustard (Brassica juncea L.) is a Brassica plant of the family Cruciferae, which is fast and capable of high tillering ability. Its growth cycle is short, the biomass of the upper part of the ground is large, it can enrich a variety of heavy metals and has great potential for application in phytoremediation. Alfalfa (Medicago Sativa L.) is a kind of perennial legume herbaceous plant, which is a kind of high yield. At present, there are few studies on the cadmium absorption capacity of ryegrass, alfalfa and India mustard, as well as the molecular mechanism level of cadmium resistance genes in the related plants. Therefore, the test is made of ryegrass (breeds for Bond and albad), India mustard and alfalfa as a test. Through soil culture test, the soil Cd pollution level (0,75150300 and 600 mg kg~ (-1)) was simulated by soil culture test. The difference in the growth of different cadmium enriched plants, the activity of antioxidant enzymes, the difference of Cd content and accumulation, the maximum Cd absorption value of different plants, and the expression of cadmium resistance gene through RT-PCR were studied. In order to provide theoretical basis for rational control and restoration of soil Cd pollution from the molecular mechanism, the main results are as follows: (1) the dry weight of ryegrass (Bond and arbor) and the increase of total dry weight of plant with the increase of soil cadmium pollution level first and then decrease the trend of.75 mg. Kg~ (-1) Cd, 150 Mg. Kg~ (-1) Cd stimulated ryegrass (Bond) and ryegrass (albad) to grow. The dry weight of the upper ground was 10.06% and 25.84%. respectively. The dry weight of ryegrass (Bond and albad) was much higher than that of India mustard and alfalfa. (2) the photosynthetic system parameters of 3 cadmium enriched plants were all under different levels of cadmium pollution. The content of 3 cadmium enriched MDA decreased with the increase of cadmium level in soil. When exogenous cadmium level was 600 mg. Kg~ (-1), the MDA content of ryegrass (Bond and albad), alfalfa and India mustard root were significantly lower than those of control (P0.05), which decreased by 49.62%, 44.44%, 40.74% and 51.68%., respectively, with cadmium stress, respectively. SOD, POD overall increased first and then decreased, and CAT decreased. (3) ryegrass (Bond and albad), alfalfa and India mustard have strong enrichment ability to cadmium, and the content of cadmium in all parts of root is above ground. And at the level of 150 mg. Kg~ (-1), 75 mg. Kg~ (-1) Cd, ryegrass (Bond and albad), alfalfa and India. The content of cadmium in the ground mustard was 171.827 mg. Kg~ (-1) and 169.122 mg. Kg~ (-1), 356.463 mg. Kg~ (-1) and 308.735 mg. Kg~ (-1), which were above the critical value of the hyperconcentration plant (100). (4) the best removal rate of cadmium in the soil of ryegrass (Arbor) was 16.24%, and the other was 16.24%. The removal rate of cadmium in soil was the best under the level of Alfalfa at the level of cadmium, which was 19.82%, 30.72% and 26.78%., considering the accumulation of soil and the removal rate of cadmium in soil. The overall removal rate of soil Cd could be improved by a variety of plant rotation methods. (5) under the level of Cd pollution, the soil cadmium was mainly EXC-Cd and FDC was as high as 55.09%~83.23%.. The order of the size of Cd FDC was as follows: EXC-CdCAB-CdFeMn-CdRES-CdOM-Cd. increased with the increase of soil cadmium level and the FDC of EXC-Cd. Except OM-Cd, the cadmium speciation of the other soil was significantly positively correlated with the CD content of plant and root (P0.01). (6) 3 species of plant materials, ryegrass (Bond and arbor), were tested. The BCF of alfalfa and India mustard were more than 1, and India mustard alfalfa (alfalfa) ryegrass (albad) ryegrass (bond) and India mustard had the strongest enrichment ability to cadmium. All treatment TF values were less than 1, the size order was ryegrass (A Bode) alfalfa India mustard, and ryegrass (albad) was the most effective gathering soil. (7) the variation trend of OAS and IRT expression levels of 2 cadmium related genes (family) related genes (family) of ryegrass (Bond and arbor) in ryegrass (Bond and arbor) was significant difference between different cadmium levels, and there were significant differences among the same species. The expression of ryegrass (Bond) OAS and IRT gene (family) was more sensitive to cadmium treatment, and in 75 mg. Kg~ (-1) Cd The OAS and IRT gene (family) increased significantly at 150 mg. Kg~ (-1) levels, and the up-regulated range was significantly lower than that of ryegrass (bond). The same gene in the same family was the same in the same family.
【學(xué)位授予單位】：西南大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：X53;X173

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本文編號(hào)：2079665