【作者】 亓琳；

【导师】 李小刚；

【作者基本信息】 兰州大学 ， 生态学， 2014， 博士

【摘要】 我国西北局部地区存在放射性锶污染问题。本文以治理放射性锶(90Sr)污染土壤为目的,采用稳定性锶-88模拟放射性锶-90同位素的方法,砂培盆栽试验和土培盆栽试验相结合,系统研究了锶在麦类作物(6个小麦品种,4个大麦品种、8个皮燕麦品种和8个裸燕麦品种)中的吸收、分配、转运和积累的规律特征。本文旨在筛选出对锶具有吸收浓度高,生物量大,适应当地生态条件的作物品种,并为核素污染土壤的植物修复做好前期工作准备。主要结果如下：1.2008-2009年砂培盆栽试验对26个麦类作物品种(6个小麦品种,4个大麦品种、8个皮燕麦品种和8个裸燕麦品种)的锶富集特征以及锶在不同器官的分配规律进行比较。本试验结果表明在锶对麦类作物品种的生物量没有显著影响。不同作物的地上锶富集浓度之间相比,裸燕麦最高,大麦,皮燕麦次之,小麦最低。同种作物的不同器官的锶富集浓度相比,大麦的根部最高,而小麦、皮燕麦和裸燕麦则是叶片最高。不同作物的根冠转移系数(TLFs)相比,在100mgkg-1Sr处理中,裸燕麦最高(0.653～1.959),其次是皮燕麦(0.480～1.476),小麦(0.474～0.824)和大麦(0.286～0.574)最低。在500mgkg-1Sr处理中,裸燕麦最高(1.041-2.741),其次是皮燕麦(0.396～1.890),小麦(0.223～0.804)和大麦(0.303-0.798)最低。植物修复材料可以在裸燕麦中选择。其中,内蒙科艺1号(裸燕麦)的地上锶富集浓度和根冠转移系数在26个麦类作物品种中都是最高的。内蒙科艺1号(裸燕麦)的地上锶富集浓度在100和500mgkg-1Sr处理中分别为2213mgkg-1和7865mkg-1, TLF分别为1-959和2.741。裸燕麦内蒙科艺1号具备超富集植物的特征(TLF>1),显示出很强的锶富集能力,是潜在的锶污染土壤的植物修复材料。小麦的地上锶浓度和转移系数都是最低的,表现出金属排除型植物的特征,可以作为锶轻度污染地区食用的作物类型。2.2009-2010年砂培盆栽试验比较了两个裸燕麦基因型(坝莜3号和内蒙科艺1号)在锶处理下苗期的植物生长以及抗氧化酶系的生理响应。实验结果如下：(1)锶处理显著减少了坝莜3号生物量的积累,包括地上生物量(16%)、根部生物量(18%)、根长(26%)和根面积(23%)。低浓度锶处理没有减少内蒙科艺1号生物量的积累。内蒙科艺1号地上生物量在高浓度锶处理下有所减少,但高于对照11%。(2)根部和叶片的锶富集浓度随着处理中锶浓度的增加而增加。内蒙科艺1号的锶富集浓度在低浓度锶处理下(0.15和0.6mMSr)接近或高于坝莜3号。而在高浓度锶处理下(3和6mMSr),内蒙科艺1号的锶富集浓度显著(约2倍)高于坝莜3号。(3)TLFs随着处理中锶浓度的增加先升高后降低。内蒙科艺1号的TLFs(1.66～2.03)在所有锶添加处理中都高于坝莜3号的TLFs(0.87-1.63)。(4)叶片和根部应对锶诱导的氧化胁迫响应不同。叶片的MDA含量低于根部,叶片的SOD和POD活性比根部高。(5)内蒙科艺1号的叶片和根部的MDA含量低于坝莜3号,内蒙科艺1号的叶片和根部的SOD、POD和CAT活性高于坝莜3号。以上结果说明在植物内部不同抗氧化防御系统应对锶的压力在裸燕麦基因型间存在差异性。不同裸燕麦基因型间对金属锶富集能力的不同有可能源于其内部不同抗氧化防御系统应对锶的压力的差异。3.2010-2011年土培盆栽试验比较了成熟期四个裸燕麦基因型(坝莜3号,蒙麦8313,定莜6号和内蒙科艺1号)的不同器官的锶的富集浓度和分布特征,比较不同燕麦基因型的植物修复效果。结果表明,锶富集浓度随着锶处理的增加而升高。内蒙科艺1号的锶富集能力最强。四个基因型中内蒙科艺1号的地上锶富集浓度都是最高的。TLFs在所有锶处理中高于其它基因型,且在高浓度锶处理下最高(1.37)。内蒙科艺1号从土壤中清除锶的百分比在所有锶处理中高于其它基因型,且在高浓度锶处理下最高(3.34%)。内蒙科艺1号富集锶主要分布在地上部分,叶片的锶富集浓度最高,而籽粒的锶富集浓度最低。锶主要分布在燕麦的非食用部分。叶片锶分布比例范围为41%-55%,籽粒锶分布比例范围为3%～5%。内蒙科艺1号的平均EC值的范围为0.521-1.343,接近于在矿区发现的超富集植物的EC(0.33～1.38)。经土培盆栽试验再次验证,内蒙科艺1号显示出很强的锶富集能力,可以作为一种有效的理想的锶污染土壤的植物修复材料。此外,本试验比较了锶对土壤酶活性(脱氢酶、β-糖苷酶、脲酶、酸性磷酸酶和碱性磷酸酶)以及微生物量碳氮的影响。结果发现锶显著影响了脲酶活性和微生物量碳氮,分别减少了39%,27%和40%。脲酶和微生物量碳氮对土壤锶污染较为敏感。脲酶和微生物量碳氮可以作为监测土壤锶污染程度的敏感指标。小麦的地上锶浓度最低,转移系数最低,可以考虑作为锶低度污染地区食用的作物品种。锶污染土壤的植物修复材料可以在裸燕麦中选择。内蒙科艺1号的地上锶富集含量最高,该基因型可以作为一种有效的理想的植物修复材料。脲酶和微生物量碳氮对土壤锶污染较为敏感。脲酶和微生物量碳氮可以作为监测土壤锶污染程度的敏感指标。本论文结果为农田核素污染土壤的植物医治做好前期准备工作。更多还原

【Abstract】 Radioactive strontium pollution problems exist in parts of northwest China. For the purpose of controlling radioactive strontium (90sr) contaminated soil, the stable isotopes of strontium-88were adopted to simulate radioactive isotopes of strontium-90,26cultivar species (6wheat varieties,4barley varieties,8husk oats varieties and8naked oats varieties) were chosen as experimental material, the combination of sand pot experiment and soil culture pot experiment were carried out to research strontium on the absorption, distribution, transportation and accumulation patterns in wheat, oat and barley crops. This article is supposed to select species which has such advantages as high concentration, big bio mass, adapt to the local ecological conditions. This work is ready for the early work for phytoremediation of nuclide contaminated soil.The main results were as follows:1.2008-2009, sand pot experiment was carried out to investigate the enrichment characteristics of strontium and strontium distribution patterns in different organs of26varieties of wheat and barley crops (6wheat varieties,4barley varieties,8husk oats varieties and8naked oats varieties). The results showed that strontium had no significant impact on crop biomass. Compared strontium enrichment concentration between different crop varieties, the highest was naked oats, followed by barley, husk oats, minimum was wheat. Compared strontium concentration in different organs of same crop varieties, roots of barley was the highest, while leaf of wheat, oats and naked oats was the highest. Compared transfer coefficient (TLFs) in different crops, in100mgkg-1Sr treatment, naked oats was the highest (0.653～1.959), followed by skin oats (0.480～1.476), wheat (0.474～0.824) and barley (0.286～0.574). In500mgkg-1Sr treatment, naked oats was the highest (1.041～2.741), followed by skin oats (0.396～1.890), wheat (0.223～0.804) and barley (0.303～0.798). Phytoremediation materials can be chosen in naked oats. Among them, the Inner Mongolia technical arts (1naked oats) the floor of the enrichment of strontium concentration and root cap transfer coefficient in26varieties of wheat and barley crops are the highest. At100and500mgkg-1Sr treatments, strontium enrichment concentration of Neimengkeyi-1(naked oats) was2213mgkg-1and7865mgkg-1respectively, TLF was1.959and2.741, respectively. Neimengkeyi-1(naked oats) has the characteristics of hyperaccumulator (TLF>1), showed strong ability of strontium concentration, and was recommendable as potential strontium contaminated soil materials for phytoremediation. Strontium concentration and translocation factor in wheat varieties was the lowest, showed the characteristics of metal excluding plants, and could be used as edible crops grown in strontium lightly polluted areas.2. In2009-2010, this experiment compared the plant growth and physiological response of antioxidant enzyme system of two naked oat genotypes (Bayu-3and Neimengkeyi-1) at seedling stage in sand pot experiment. The results showed that:(1) strontium addition significantly reduced the bio mass of Bayou-3, including the ground bio mass (16%), root biomass(18%), root length (26%) and the root area (23%). Low concentration of strontium addition did not reduce Neimengkeyi-1biomass. Neimengkeyi-1aboveground biomass decreased under high concentration strontium treatment, but higher than control by11%.(2) The strontium enrichment concentration in roots and leaves increased with increased addition of strontium concentration. Strontium enrichment concentration of Neimengkeyi-1at low concentration of strontium treatments (0.15and0.15mM Sr) was close to or higher than the Bayou-3. And under the high concentration of strontium treatments (3and6mM Sr), strontium enrichment concentration of Neimengkeyi-1was significantly higher than Bayou-3(about2times higher).(3) TLFs first rose than dropped with the increase of strontium concentration treatments. The TLFs of Neimengkeyi-1(1.66～2.03) were higher than the TLFs of Bayou-3(0.87～0.87) in all strontium addition treatments.(4) The strategies of Leaves and roots responding differently to strontium treatments induced oxidative stress response. Leaf MDA content was below the root, leaf SOD and POD activity was higher than the root.(5) MDA content in the leaves and roots of Neimengkeyi-1was below the Bayou-3, SOD, POD and CAT activity in leaves and roots of Neimengleyi-1of is higher than Bayou-3. The all results showed that the antioxidant defense system within the plant to responding the strontium stress in naked oats differently between genotypes. The different ability of naked oat genotypes responding to metal strontium stress possibly originated from its internal antioxidant system to cope with strontium pressure stress.3. In2010-2011, the four naked oats varieties (Bayou-3, Mengmai-8313, Dingyou-6and Neimengkeyimai-1) were chosen in soil culture pot experiment. This experiment investigated metal strontium concentration distribution and enrichment in different organs in harvest between different crop varieties, we found that mature oats had higher strontium enrichment ability, strontium metal were mainly distributed in leaf and stem; Under the treatment of different concentrations of strontium stress, the concentration of the leaves was the highest, the concentration of the grain was the lowest; Under different concentration of strontium stress treatment, Neimengkeyimai-1above strontium enrichent concentration was the highest of four genotypes. Neimengkeyimai-1can be used as a kind of effective ideal phytoremediation plant for strontium pollution. In addition, this experiment compared the soil enzyme activity (dehydrogenase, β-glycosidase, urease, acid phosphatase and alkaline phosphatase) and microbial biomass carbon and nitrogen. Urease, MBC and MBN were sensitive to soil strontium pollution.In summary, phytoremediation materials can be choose in naked oats varieties. Strontium concentration of wheat was the lowest, translocation coefficient of wheat was the lowest, and wheat can be considered as food-grade crop varieties in low-dose strontium metal pollution area. Urease, MBC and MBN was sensitive to soil pollution of strontium. Shoot Sr enrichment concentration of Neimengkeyimai-1was the highest. Neimengkeyimai-1can be used as an effective ideal phytoremediation plant. Our results prepared for remediation of strontium nuclides polluted farmland.更多还原