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《西北农林科技大学》 2017年
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利用密旋链霉菌和生物炭对工矿业污染土壤植物修复及降低重金属毒性的研究

Ali Amjad  
【摘要】:生物圈中潜在有毒重金属元素的过度排放成为一个全球性的问题。工业化的快速发展所引起的农业活动不断扩大、金属冶炼、矿产资源开发、煤炭燃烧以及城市固体废弃物的不当处置都对自然环境造成严重污染。重金属元素能够对植物和人体健康构成危害,污染土壤和地表(下)水,降低土壤质量并改变自然生态系统。同时能够阻碍植物叶绿素的合成,阻碍植物呼吸,抑制植物和土壤中酶的活性。尽管人们采取了多种技术措施来修复土壤中重金属,其中包括物理、化学和生物修复技术,但目前仍缺乏经济有效的土壤重金属污染修复技术。近年来,由于微生物强化的植物修复技术和添加有机改良剂具有成本低廉和修复效果稳定的优势,引起科学界的广泛关注。本实验的目的在于通过向三种不同重金属污染水平土壤中单施和混施密旋链霉菌(Streptomyces pactum,Act12)和生物炭,分析两者间的相互作用。供试土壤采自陕西潼关(TG)、陕西凤县(FC)和湖南郴州(CZ)。该研究旨在利用链霉菌和生物炭提高高粱和芥菜的植物修复能力并降低重金属元素对植物的毒性。主要研究结论如下:(1)凤县和潼关土壤中添加链霉菌和麦饭石堆肥后研究表明,凤县土壤种植芥菜的茎叶中Zn、Pb、Cd和Cu的含量分别比对照增加了7.28、54.21%、16.17%和8.10%;潼关土壤种植的芥菜茎叶中Zn、Pb和Cu的含量分别比对照增加了40.14%、82.15%和52%,但是茎叶中Cd含量未检出。根系中Cd和Cu含量分别增加了17%和33%。这表明,植物茎叶吸收重金属的量与Act12用量呈正相关。凤县和潼关土壤种植芥菜的根茎干重、叶绿素含量和类胡萝卜素含量与Act12用量之间也存在显著相关性。在潜在有毒重金属元素的诱导下,芥菜中抗氧化物酶活性(POD、PAL、PPO和CAT)的变化反映出植物防御机制的增强。通过富集系数(BCF)、转运系数(TF)和金属提取量(MEA)进一步评估芥菜对重金属的吸收能力。(2)向凤县和潼关土壤中添加竹炭后对重金属的钝化稳定化效果进行了研究,结果表明,向矿区重金属污染土壤中施加竹炭能够钝化重金属(Zn,Pb,Cd和Cu)的有效性。施加竹炭后凤县和潼关土壤pH值和EC值增加,重金属的生物有效性降低,但潼关土壤中Pb和Cu除外。添加竹炭后能够降低芥菜茎叶和根系对重金属的吸收。生物学研究表明竹炭能够促进植物茎叶和根系的生长,提高生物量、叶绿素和类胡萝卜素含量。竹炭能够改善土壤的健康状况,提高土壤酶(β-葡糖苷酶、碱性磷酸酶和脲酶)活性。抗氧化物活性(POD,PPO,CAT和SOD)也被用来评价供试植物的生理状况,评估重金属元素作用下对芥菜生长造成的影响。总的来说,添加竹炭后降低了凤县和潼关土壤重金属元素的移动性和生物有效性,这一结论也通过BCF,TF和MEA值也得到验证。(3)1%竹炭添加水平下,不同Act12添加量促进潼关、凤县和郴州土壤种植高粱的生长和对重金属元素的吸收。添加竹炭和Act12后土壤pH值和EC值发生了明显变化。潼关、凤县和郴州土壤中Zn和Pb的浸提态含量较高。潼关和郴州Cd浸提态含量减小,但凤县土壤该值则保持不变。Act12和竹炭联合施用后潼关土壤种植高粱茎叶和根系中Zn和Pb的含量增加,郴州土壤种植的高粱茎叶中重金属含量增加而根系中含量降低。同样地,凤县土壤种植的高粱茎叶中Zn、Pb和Cu含量显著增加,Cd含量降低。然而,Act12和竹炭联合施用后植物根系中Zn和Pb含量降低,而Pb和Cu的含量增加。植物茎叶中Cd含量未检出是因为大部分Cd贮存于植物根系中。郴州土壤种植的高粱茎叶和根系吸收Cd含量降低。添加Act12和竹炭后植物茎叶叶绿素含量、生物量增加,植物茎叶中抗氧化酶活性(POD,PAL,PPO)和丙二酮(MDA)显著降低。BCF、TF和MEA值也证实了Act12对重金属在土壤中迁移作用的影响。下一步的研究中,通过种植超富集植物将进一步证实Act12和生物炭在修复重金属污染土壤中的作用,为评价重金属元素在食物链中的转运提出新的见解。因此,密旋链霉菌和生物炭能够增加植物修复效率和降低重金属的生物毒性,并且提高植物和污染土壤中相应酶活性。
【关键词】:生物炭 酶活性 土壤污染 密旋链霉菌 痕量元素 芥菜 采矿 植物修复 稳定化
【学位授予单位】:西北农林科技大学
【学位级别】:博士
【学位授予年份】:2017
【分类号】:X53;X172
【目录】:
  • Abstract6-9
  • 摘要9-20
  • CHAPTER 1. INTRODUCTION AND REVIEW OF LITERATURE20-51
  • 1.1 Potentially toxic trace elements (PTEs)20-21
  • 1.2 Sources of potential toxic trace elements (PTEs) in the environment21-24
  • 1.3 Global overview of PTEs pollution24-26
  • 1.4 Chinese scenario of soil pollution26-28
  • 1.5 Detrimental impacts of PTEs on public health and plants28-33
  • 1.5.1 Zinc (Zn)29
  • 1.5.2 Lead (Pb)29-30
  • 1.5.3 Cadmium (Cd)30-31
  • 1.5.4 Copper (Cu)31
  • 1.5.5 Nickle (Ni)31-32
  • 1.5.6 Mercury (Hg)32
  • 1.5.7 Arsenic (As)32
  • 1.5.8 Chromium (Cr)32-33
  • 1.5.9 Aluminum (Al)33
  • 1.6 Soil remediation techniques33-36
  • 1.7 Phytoremediation and its importance36-39
  • 1.8 Microbes assisted phytoremediation39-41
  • 1.9 Streptomyces pactum for phytoremediation: A novel soil microorganism41-47
  • 1.9.1 Fate of plants used in the phytoremediation of PTEs42-43
  • 1.9.2 Immobilization of PTEs in polluted soil using organic amendments43-44
  • 1.9.3 The nature of biochar and its potential to adsorb PTEs44-46
  • 1.9.4 Limitations of biochar as soil amendment46-47
  • 1.10 Effect of PTEs on enzyme activity47-50
  • 1.10.1 Soil enzymatic activities affected by PTEs47-49
  • 1.10.2 Plant antioxidant activities as function of soil contamination49-50
  • 1.11 Research objectives50-51
  • CHAPTER 2. MATERIALS AND METHODS51-64
  • 2.1 Sites Description51-52
  • 2.1.1 Tongguan (TG)51
  • 2.1.2 Feng County (FC)51-52
  • 2.1.3 Chenzhou (CZ)52
  • 2.2 Materials Collection52-54
  • 2.2.1 Collection of contaminated soil samples52-53
  • 2.2.2 Isolation of Streptomyces pactum53
  • 2.2.3 Raw materials for composting53-54
  • 2.2.4 Biochar collection54
  • 2.3 Experimental Methods54-63
  • 2.3.1 Soil, compost and biochar analysis54-58
  • 2.3.2 Plant analysis58-63
  • 2.3.2.4 Determination of total PTEs content in plant samples59
  • 2.3.2.5 Determination of antioxidant enzymatic activities in plant59-62
  • 2.3.2.6 Measurement of MDA62-63
  • 2.3.2.7 Phytoextraction indices63
  • 2.4 Quality control and statistical analysis63-64
  • CHAPTER 3. ROLE OF STREPTOMYCES PACTUM IN PHYTOREMEDIATION OF TRACE ELEMENTS IN MINE POLLUTED SOILS OF SHAANXI, NORTHWEST CHINA64-82
  • 3.1 Introduction64-65
  • 3.2 Materials and Methods65-67
  • 3.2.1 Samples collection65
  • 3.2.2 Experiment Methods65-67
  • 3.3 Results and Discussion67-81
  • 3.3.1 Characteristics of the studied soils and medical stone compost67-69
  • 3.3.2 Effect of Streptomyces pactum on PTEs uptake by Brassica juncea69-74
  • 3.3.3 Effect of Streptomyces pactum on growth attributes of Brassica juncea74-77
  • 3.3.4 Effect of Streptomyces pactum on leaf antioxidant activities77-79
  • 3.3.5 Phytoextraction indices of trace elements79-81
  • 3.4 Conclusions81-82
  • CHAPTER 4. USING BAMBOO BIOCHAR WITH COMPOST FOR STABILIZATION AND PHYTOTOXICITY REDUCTION OF TRACE ELEMENTS IN MINESCONTAMINATED SOILS OF SHAANXI PROVINCE, CHINA82-102
  • 4.1 Introduction82-84
  • 4.2 Materials and Methods84-86
  • 4.2.1 Materials collection84
  • 4.2.2 Experimental Methods84-86
  • 4.3 Results and Discussion86-101
  • 4.3.1 Characteristics of studied soils, medical stone compost and bamboo biochar86-88
  • 4.3.2 Effect of biochar amendments on soil pH and EC88-89
  • 4.3.3 Effect of biochar amendments on PTEs bioavailability89-90
  • 4.3.4 Effect of biochar on PTEs translocation in Brassica juncea shoot90-92
  • 4.3.5 Effect of biochar on PTEs accumulation in Brassica juncea root92-93
  • 4.3.6 Phytotoxicity assay of Brassica juncea in polluted soils93-96
  • 4.3.7 Effect of biochar on the soil enzymatic activities96-97
  • 4.3.8 Effect of biochar on the plant antioxidant enzymes97-100
  • 4.3.9 Phytoextraction indices of PTEs100-101
  • 4.4 Conclusions101-102
  • CHAPTER 5. INTEGRATED EFFECT OF STREPTOMYCES PACTUM (ACT12) AND BIOCHAR ON THE PHYTOEXTRACTION OF POTENTIAL TOXIC TRACEELEMENTS IN CONTAMINATED SOILS102-129
  • 5.1 Introduction102-104
  • 5.2 Materials and Methods104-105
  • 5.2.1 Materials collection and Act12 isolation104
  • 5.2.2 Experimental methods104-105
  • 5.3 Results and Discussion105-127
  • 5.3.1 Physico-chemical characteristics of soil, compost and biochar105-108
  • 5.3.2 Effect of biochar and Act12 on soil pH and EC108-110
  • 5.3.3 Effect of biochar and Act12 on bioavailable fraction of PTEs110-111
  • 5.3.4 Effect of biochar and Act12 on phytoextraction of PTEs in sorghum shoots111-115
  • 5.3.5 Effect of biochar and Act12 on phytoextraction of PTEs in sorghum root115-117
  • 5.3.6 Plant growth promotion by biochar and Act12117-120
  • 5.3.7 Effect of biochar and Act 12 on the soil enzymatic activities120-123
  • 5.3.8 Effect of biochar and Act12 on the plant anti-enzymatic activities123-124
  • 5.3.9 Lipid peroxidation product124-125
  • 5.3.10 Phytoextraction indices of PTEs125-127
  • 5.4 Conclusions127-129
  • SUMMARY AND MAIN CONCLUSIONS129-131
  • SUGGESTIONS AND RECOMMENDATIONS131-132
  • REFERENCES132-150
  • NOMENCLATURE150-152
  • ABOUT THE AUTHOR152-153
  • PUBLISHED PEER REVIEWED PAPERS (SCI)153-156

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