【作者】 张莹；

【导师】 铁梅；

【作者基本信息】 辽宁大学 ， 环境科学， 2013， 硕士

【摘要】 硒是人体必需的一种营养元素，有许多重要的生理功能。目前人体补硒有多种途径，富硒食品倍受欢迎。廉价的富硒食品更易被普通消费者接受。萝卜作为重要的经济作物，物美价廉，研究富硒萝卜的种植条件，种植与推广富硒萝卜有重要的价值。工农业的发展使重金属对农作物的影响日益严重。研究萝卜中硒与重金属的相互作用及作物中硒与重金属的形态和含量，对重金属轻度污染地区富硒作物的开发有积极作用。1.本研究通过对石墨炉原子吸收法测定萝卜中硒、铅、镉测定的方法的优化，建立石墨炉原子吸收法测定萝卜中硒、铅、镉的最佳方法。以1.0mg·mL^-1Cu（NO3）2为基体改进剂，7.0mA灯电流，灰化温度800℃，原子化温度2500℃是测定不同萝卜中硒含量的适宜条件。5.0mA灯电流，260℃灰化温度，1800℃原子化温度为测定萝卜中镉含量的最佳方法。12.0mA灯电流，500℃灰化温度，2200℃原子化温度为测定萝卜中铅含量的最优条件。在优化条件下测定Se的加标回收率在99.6%～106.0%之间，方法相对标准偏差为1.19%，检出限为0.79μg·L^-1。Cd的加标回收率在87.2%～103.7%之间，方法相对标准偏差为4.40%。Pb加标回收率在96.7%～123.9%之间，方法相对标准偏差为2.04%。石墨炉原子吸收法测定植物样品中的硒、铅、镉方法简便、灵敏高、稳定性较好，适用于萝卜中硒、铅、镉的分析测定。2.田间试验的方法对红樱桃、白樱桃、青水果三个品种萝卜进行富硒栽培。三种萝卜中硒的含量随土壤中施加的硒肥的浓度的增加而增加。三种萝卜对硒的富集能力：红樱桃>青水果>白樱桃。采用水、乙醇、0.1moL·L^-1醋酸、0.1moL·L^-1NaCl、0.1moL·L^-1NaOH、0.05moL·L^-1NaHCO3、0.05moL·L^-1Tris-HCl试剂等提取剂对植物样品中不同形态的硒进行分离提取。结果表明：样品中的蛋白结合态的硒含量最多，样品中醇溶态的硒含量最少，硒主要以易与蛋白质结合的形态存在。3.采用盆栽试验的方法，研究不同含量的硒、镉和铅单一和复合作用对萝卜生长及其对硒、镉、铅吸收的影响。结果表明，适量的硒可以促进萝卜的生长，表现为萝卜出芽率、叶片SPAD值、生物量等的增加。镉单一污染时，萝卜生物量与外源镉含量呈显著负相关，镉显著抑制萝卜的生长。铅单一污染时，铅对萝卜地上部分的生长有毒害作用，而只在铅浓度较高时(>400mg·kg^-1)时才对地下部分生物量有较大影响。土壤中低浓度的硒对镉和铅具有拮抗作用，可以促进萝卜的生长。萝卜地下部对硒的吸收能力大于地上部，对硒的富集效果明显。在硒镉复合作用处理中，镉对低浓度硒的吸收无明显影响，硒能显著降低萝卜对镉的吸收；在硒铅复合作用处理中，向不同浓度硒处理组加入铅时（即Se+Pb处理组），Pb的加入显著抑制了萝卜的生长，萝卜发芽10天后幼苗全部死亡；而向不同浓度铅处理组加入硒（即Pb+Se处理组），萝卜能维持生长，硒能显著降低萝卜对铅的吸收，铅的吸收量平均降低40%。更多还原

【Abstract】 Selenium is one of the essential nutritional elements, and has many importantphysiological functions. There have been many different ways that human can supplyselenium so far, and Se-enriched food is becoming more and more popular Thecheaper Se-enriched food is more easily accepted by ordinary consumers. Radish asan important economic crop, exhibit high quality and inexpensive, so investigatingthe planting conditions of Se-enriched Radish, cultivating and spreading ofSe-enriched radish have important values. The effect of heavy metals on cropgrowing is more and more serious because of the development of industry. Investigatethe chemical speciation and content of heavy metals and selenium, as well as theinteraction between heavy metals and selenium in Radish. This research will have apositive effect on development of selenium-rich crops in lightly heavy metal pollutedareas.1. In this thesis, through the optimization method of Selenium, Lead, Cadmiumin the samples determined by graphite furnace atomic absorption method, establishthe best method of Selenium, Lead, Cadmium in Radish determined by the graphitefurnace AAS. The results showed that1.0mg·mL^-1Cu（NO3）2as matrix modifier,7.0mA lamp current, ashing temperature800℃, atomization temperature2500℃were the optimum conditions of selenium determination in different Radish.5.0mAlamp current,260℃ashing temperature, atomization temperature1800℃were theoptimum conditions of Cadmium determination in the Radish.12.0mA lamp current,500℃ashing temperature, atomization temperature2200℃were the optimumconditions of Pb determination in radish. Under the optimized conditions, therecovery of Se was between99.6%¹06.0%, relative standard deviation was1.19%,the detection limit was0.79μg/L. The recovery rate of Cd was87.2%¹03.7%,relative standard deviation was4.40%. The recovery of Pb was96.7%¹23.9%,relative standard deviation was2.04%. The graphite furnace AAS is a simple,sensitive, stable method to determinate Selenium, Lead, Cadmium in plant samples,and it is suitable for Selenium, Lead, Cadmium determination in radish. 2. With the method of field test, three cultivars of Radish: red cherry radish,white radish, green fruit radish were Se-enriching cultivated. The concentrations ofselenium in three cultivars of Radish were positively related to Selenium in soils. Theselenium enrichment ability of three cultivars of radish: red cherry> green fruit>white cherry. By using reagent extraction agents, water, ethanol,0.1moL·L^-1acetic acid,0.1moL·L^-1NaCl,0.1moL·L^-1NaOH,0.05moL·L^-1NaHCO3,0.05moL·L^-1Tris-HCl,the different chemical speciation of selenium was extracted from the plants. Theresults showed that: in the samples protein bound selenium content were the mostabundant, the selenium content of alcohol soluble samples wre the least abundant,selenium was easier to combine with protein.3. In order to investigate the effects of different concentrations of Cadmium （Cd），Lead（Pb）, selenium（Se） and their combination on the growth of Radish and theuptake of Cd, Pb and Se in the plants, pot experiments are carried out. The resultsshowed that, a proper quantity of selenium could promote the growth of the Radish,showing up as Seed budding rate, leaf SPAD values,and biomass etc. Radish biomasswas negatively correlated with exogenous cadmium when radish was polluted by Cditself; cadmium inhibited the growth of radish. Pb leads poisonous effect on the partof radish on the ground, but only in the higher concentration will make (Lead>400mg·kg^-1) a great influence on the underground biomass. The concentration ofselenium in the soil had antagonistic effects on Cadmium and Lead, and promoted thegrowth of Radish. The absorption ability of selenium was stronger in root than inshoot, at the same time the root was obviously enriches more selenium than the shoot.In the composite effect of selenium and cadmium, no obvious effect on cadmiumuptake of low concentration of selenium; selenium can significantly reduce the Cdabsorbed by radish. the Se+Pb treatment group, the addition of Pb significantlyinhibits the growth of the radish, radish germination in10days seedlings all died; andgroup Pb+Se, radish maintain growth, selenium can significantly reduce theabsorption of Lead that is absorbed by radish, in addition, the average absorption ofLead drops40%.更多还原