【作者】 陈海宁；

【导师】 张民；

【作者基本信息】 山东农业大学 ， 土壤学， 2012， 博士

【摘要】 碘和硒对人体健康起重要作用的微量元素，碘和硒缺乏时能导致人体患多种疾病。因此，如何提高缺碘和缺硒地区人类食物中的碘和硒含量对防治碘和硒缺乏病的发生具有重要意义。传统的补碘和补硒存在一些弊端，如产生毒副作用。因此，只有当无机形式的碘和硒转化成具有生物活性的碘和硒时，通过食物链补碘和硒，才具有普遍的意义。本研究采用生菜种子毒性试验、樱桃番茄幼苗水培试验，结合生物统计手段，系统研究了控释碘（硒）产品的有效成分碘和硒对作物生长发育的影响；并以生菜和樱桃番茄两种蔬菜为研究对象，采用土培方式，系统地探讨了生菜的富碘机制以及控释碘肥对土壤淋溶状况的影响，同时深入地研究了樱桃番茄的富碘富硒特性及控释碘（硒）对其生长发育及品质的影响。主要研究结果如下：1.包膜控释碘（硒）肥在25℃水中的累积释放曲线呈“S”型，其在静水中的具体释放特征为：其释放过程分为释放速率逐渐上升期、释放高峰期和释放速率逐渐下降期三个阶段，整个释放过程有一个释放高峰阶段。研究中测得的初期养分释放率、养分释放期等参数符合缓控释肥国家标准，因此控释碘肥和硒肥在作物上应用时，可以在作物生育期内稳定供给碘和硒等营养元素。2.生菜种子发芽试验结果表明，随着IO3ˉ浓度的增加，生菜种子的萌发指标和幼苗生长及过氧化物酶活性指标均随之增加。当IO3ˉ的浓度为80μmol L-1时，生菜种子的发芽势、发芽率、发芽指数和活力指数较对照提高了22.13%²5.23%，差异均达显著水平；生菜幼苗的根长、茎长、鲜重和干重均为最大值，较对照提高了16.09%¹13.71%；生菜幼苗的SOD、POD和CAT活性均显著高于对照，提高了32.74%⁶5.71%；生菜幼苗MDA含量与对照相比无显著差异。低浓度Iˉ（10⁴0μmol L-1）刺激种子萌发。当Iˉ浓度为80μmol L-1时，生菜种子的发芽势、发芽率、发芽指数和活力指数较对照降低了32.78%³6.83%，其幼苗的根长、茎长、鲜重和干重最低。Iˉ条件下，生菜幼苗SOD和POD活性以处理20μmol L-1最高。幼苗CAT活性随着Iˉ浓度的增加而降低，MDA含量显著高于对照。研究结果表明，生菜的萌发及幼苗生长与IO3ˉ的浓度呈显著正相关，与Iˉ的浓度呈显著负相关。此外，低浓度IO3ˉ或Iˉ与SeO₃^2-互作促进了生菜种子萌发，刺激幼苗生长，提高幼苗酶活性抗逆性；高浓度Iˉ和SeO₃^2-互作显著抑制生菜种子萌发。3. IO3ˉ和SeO₃^2-互作条件下，樱桃番茄幼苗的株高、茎粗、叶面积、干重、根系活力、叶片叶绿素含量、净光合速率、蒸腾速率、气孔导度以及脯氨酸、可溶性蛋白和可溶性糖含量均最高；幼苗叶片过氧化物酶SOD、POD、CAT和APX活性分别较对照提高了22.25%、16.74%、31.18%和37.58%，MDA含量较对照降低了20.32%。而Iˉ和SeO₃^2-互作条件下，樱桃番茄幼苗生长受到抑制，株高和叶片数分别较对照下降了19.10%和7.14%，幼苗地上部鲜重和干重显著降低，分别较对照降低了25.64%和26.32%；番茄幼苗光合性能显著减弱，Pn和Gs分别较对照降低了17.68%和8.94%，过氧化物酶活性降低，膜脂质过氧化程度加剧。Iˉ条件下，番茄幼苗的生长、光合指标和生理指标均优于碘酸根处理，但无显著差异。SeO₃^2-处理对樱桃番茄幼苗生长无显著影响。4.温室盆栽试验以普通碘肥为对照，研究控释碘肥对生菜富碘、土壤淋溶及生菜某些生理特性的影响。结果表明，施碘处理与不施碘处理相比均显著提高生菜叶片的碘含量和水溶性碘的含量。在两种施碘水平下（10和20mg kg-1土），与普通碘肥相比，控释碘酸钾和控释碘化钾均显著提高生菜叶片的碘含量，分别提高了46.60%⁶1.16%、46.59%⁵8.53%；同时提高了生菜生物量、叶片叶绿素含量、维生素C含量及抗氧化酶活性（SOD、POD和CAT），降低了叶片硝态氮和丙二醛（MDA）含量。生菜生长过程中通过其根系吸收的碘绝大部分保留在根部，且生菜地上部和根部对IO3ˉ的吸收富集量远高于Iˉ；碘在控释条件下，生菜地上部和根部对IO3ˉ和Iˉ的吸收富集量远高于普通碘肥处理。IO3ˉ处理土壤碘的淋失率要高于Iˉ处理；施用控释碘酸钾和控释碘化钾后，土壤淋溶液中碘含量峰值出现时间延后，碘淋失率显著低于普通碘肥。碘肥用量结果表明，与施碘水平10mg kg-1土相比，施碘20mg kg-1土时显著提高了生菜叶片的碘含量，但对生菜品质及生理指标无显著影响。当控释碘酸钾用量为10mg kg-1土时，生菜中碘的浓度就达8.09mg kg-1。根据成年人每日150μg d-1的需碘量，缺碘人群可以通过控制食用生菜量的多少来控制每日碘摄入量。当土壤施碘为20mg kg-1土时，生菜可食部分富集的碘就可能导致碘的过量摄入以及碘的浪费。与普通碘肥相比，控释碘肥不仅显著提高了生菜叶片对碘的富集，还减少了碘素从土壤中流失，提高了碘肥利用率，碘肥控释是培育富碘蔬菜的有效途径之一。5.土壤施碘后其淋溶液pH变化值与对照相比无显著差异，碘的施入没有对土壤的酸碱体系平衡带来冲击。土壤施入普通碘肥后，土壤淋溶液EC值变化幅度较大，而施用控释碘肥的土壤淋溶液EC值变化比较平稳。土壤施碘可促进土壤中钾钠钙镁和无机氮的淋失。6.樱桃番茄盆栽试验表明，施碘和施硒显著提高了樱桃番茄果实中碘和硒的含量，且施用释碘肥和控释碘-硒肥后其果实碘含量分别较普通碘肥提高了35.58%和28.53%，控释硒肥和控释碘-硒肥条件下果实硒含量分别较普通硒肥提高了10.89%和13.86%。土壤施用控释碘肥和控释硒肥后其樱桃番茄果实碘和硒的累积量分别较普通碘肥和硒肥提高了38.78%和19.40%。施用控释硒肥后，果实有机硒的含量显著高于普通硒肥，提高了5.19%，有机硒转化率提高了3.36%。樱桃番茄施用控释碘肥和控释碘-硒肥后，樱桃番茄果实产量增加，维生素C含量提高。此外，施用控释碘肥的处理，土壤中碘的淋失率要显著低于施用普通碘肥的处理，控释碘-硒肥和控释碘肥的淋失率分别较普通碘肥处理降低了49.02%和37.25%。控释硒肥和控释碘-硒肥处理条件下中硒的淋失率显著低于普通硒肥，分别降低了38.91%和46.61%。更多还原

【Abstract】 Iodine and selenium play an important role in human health. Iodine and selenium canlead to human suffering from various diseases.Therefore, how to improve the iodine andselenium concentrations in human food in the prevention of iodine and selenium deficiencydiseases occurrence has the vital significance.Traditional iodine and selenium supplement willhave some disadvantages. Inorganic iodine and selenium could not be well absorbed bybodies and be dangerous to human and even produces toxicity. Therefore, Iodine andselenium will have wide edible valuation only when it is transformed in to biological activeorganic iodine and selenium through food chain.In order to offer academic thereunder for producing, spreading and ecosecurity estimationof controlled-release iodine or selenium fertilizers, several experiments were conducted andbiostatistical method were used in this study. The effects of iodine, selenium and combineduse of iodine and selenium on seed germination, growth and development of plants and so onwere studied by acute toxicity and hydroponic experiment. Potted lettuce experiment wascarried to investigate the influence of controlled-release iodine （IO^-and IO₃^-） fertilizers on theiodine uptake by lettuce as well as on the growth and quality of lettuce and the influence ofiodine on soil leachate. Also, the effects of controlled-release iodate fertilizer and controlledrelease iodate-selenium fertilizers on iodine and selenium uptake, growth and quality ofcherry tomato. The main results were summarized as follows:1. The nutrient release curve of controlled-release iodine or selenium fertilizers in watershowed a shape of “S”. The nutrient release curve of controlled-release fertilizers in25℃water showed that release rate increased with time in the first stage, fastigium and decreasedwith time in the third stage. Parameters, like initial nutrient release rate, and release duration,accorded with Chinese National Slow and controlled-release fertilizers standard. Andcontrolled-release iodine or selenium fertilizers could be used for crops application research.2. Lettuce seed germination experiment results showed that seed germination indexes,seedling growth and antioxidative activities were increased with the increase of IO₃^-concentration.When the IO₃^-concentration was80μmol L-1, lettuce seed germination energy,germination rate, germination index and vigor index significantly increased by22.13%²5.23%compared with the control. Lettuce seedling root length, stem length, fresh weightand dry weight reached maximum and improved16.09%¹13.71%compared to control. The SOD, POD and CAT activities of lettuce seedlings were significantly higher than those ofcontrol, increased by32.74%⁶5.71%. And the MDA content has no significant differencecompared with control. Low concentrations of Iˉ（10,20and40μmol L-1） stimulated lettuceseed germination.When the concentration of Iˉwas80μmol L-1, lettuce seed germinationenergy, germination rate, germination index and vigor index decreased by32.78%³6.83%compared with the control. The lettuce seedling root length, stem length, fresh weight and dryweight were the lowest. The SOD and POD activities were the highest when the lettuceseedlings treated with80μmol L-1. The CAT activity of lettuce seedlings increased with theincreased Iˉconcentration, and the content of MDA was significant higher than that of control.The results also showed that the seed germination and seedling growth of lettuce showed asignificant positive correlation with IO₃^-concentration, and showed significantly negativecorrelation with Iˉconcentration. In addition, low concentration of IO₃^-and Iˉor SeO₃^2-interactions promoted seed germination of lettuce, stimulated the growth of seedlings, andincreased seedling enzyme activity resistance. However, high concentrations of Iˉand SeO₃^2-interaction significantly inhibited lettuce seed germination.3. The growth parameters （plant height, stem diameter, leaf area, and dry weight） andphysiological attributes （root activity, chlorophyll （Chl） content, net photosynthetic rate （Pn）,stomatal conductance （Gs）, transpiration rate （Tr）, and contents of proline, protein and sugar）were the greatest in the plants developed from the combination of IO₃^-and SeO₃^2-. Theincreased activities of superoxide dismutase （SOD）, peroxidase （POD）, catalase （CAT） andascorbate peroxidase （APX） were enhanced by22.25%,16.74%,31.82%and37.58%,respectively, and the lipid peroxidation was decreased by20.32%, in comparison to control. Incontrast, the combined use of Iˉand SeO₃^2- resulted in reduced growth. The plant height andleaf number were decreased by19.10%and7.14%, respectively. The seedling shoot freshweight and dry weight was significantly lower than the control, were reduced by25.64%and26.32%. The combination of Iˉand SeO₃^2- resulted in reduced photosynthesis capacity as wellas reduced activities of antioxidant enzymes, and led to serious lipid peroxidation in plants.Plants grown with Iˉalone were taller （9.1%） and more sensitive to leaf photosynthesiscompared to those with IO₃^-supply alone, whereas the activities of antioxidant enzymes andprotein content were comparable. SeO₃^2- application alone generated marginal effects onmeasured characteristics. Overall, combined use of IO₃^-and SeO₃^2- proved to be the optimumfor boosting growth in this experiment.4. A greenhouse pot experiment was conducted to assess the effects of controlled-releaseiodine fertilizers on the iodine accumulation and physiological response of lettuce in comparison with traditional iodine fertilizers. The plants were subjected to different iodinefertilizers containing two levels of iodine as iodate or iodide at10and20mg kg-1soil. Resultsshowed that all the treatments with iodine applied significantly increased concentrations ofiodine and water-soluble iodine in the leaves of lettuce. Leaf iodine nutrition developed fromcontrolled-release potassium iodate and controlled-release potassium iodide was significantlyenhanced by46.60%⁶1.16%and46.59%⁵8.53%in comparison with correspondingtraditional iodine fertilizers, respectively. The biomass product （fresh mass and dry mass ofshoot and root） and leaf chlorophyll content of lettuce grown with controlled-release iodinefertilizers were higher than those of traditional iodine fertilizers. The growth-promotingfunction was also associated with increased content of vitamin C and activities of superoxidedismutase （SOD）, peroxidase （POD） and catalase （CAT） in lettuce leaves. Application ofcontrolled-release iodine fertilizers resulted in reduced NO₃^--N content and diminished lipidperoxidation （MDA） content of lettuce leaves. The iodine uptook by lettuce mostly retained inthe root and lettuce absopted more iodine when the iodate applied. The iodine accumulation inlettuce plants treated by controlled-release iodine fertilizers was much higher than that of thetraditional iodine fertilizers treatment. The iodine content in leachate peaked withcontrolled-release iodine fertilizers were later than those with the traditional iodine fertilizers.Controlled-release potassium iodate and controlled-release potassium iodide also significantlyreduced the iodine leached rate by45.99%⁵0.97%and39.18%⁴6.29%compared totraditional fertilizers, respectively. When iodine applied rate was20mg kg^-1soil, the leafiodine content was significant higher than that of10mg kg-1soil, whereas no significantdifference was found in other indexes. Overall, controlled-release iodine fertilizers increasediodine accumulation in lettuce leaves, prevented iodine leaching and improved iodine useefficiency, proving to be the optimum for cultivating iodine-enriched vegetables. Whencontrolled-release iodate fertilizer was used as10mg kg-1soil, the iodine concentration inlettuce leaves reached8.09mg kg^-1. The iodine deficiency populations can eat quantitativelettuce to meet their daily iodine demand150μg d^-1. When the applied dosage was20mg kg^-1soil, it may lead to excessive intake of iodine in lettuce and iodine waste.5. The pH value of soil leachate had no significant difference compared with the control.The application of iodine in soil did not impact the acid-base equilibrium. The EC valuechanged more stable when the soil treated by controlled-release iodine fertilizers. Theapplication of iodine in soil could promote the leaching of K⁺, Na⁺, Ca²⁺, Mg2+and inorganicnitrogen.6. The potted cherry tomato experiment showed that the concentrations of iodine and selenium in fruits were significantly enhanced when iodine and selenium applied. Theconcentrations of iodine in fruits treated by the controlled-release iodine fertilizer andcontrolled-release iodine-selenium fertilizers increased by35.58%and28.53%compared tothe traditional iodine fertilizers. The concentrations of selenium in fruits treated by thecontrolled-release selenium and controlled-release iodine-selenium fertilizers increased by10.89%and13.86%, respectively. Applications of controlled-release iodine fertilizer andcontrolled-release selenium fertilizer resulted in significant higher iodine and seleniumaccumulation in fruits, increased by38.78%and19.40%. The organic seleniumconcentrations and conversion rate in cherry tomato fruits treated by controlled-releaseselenium fertilizers increased by5.19%and3.36%, respectively, comparing with traditionalselenium fertilizers. The cherry tomato fruit yield and content of vitamin C increased unferthe application of controlled release fertilizers. In addition, application of controlled-releaseiodine-selenium fertilizer and controlled-release fertilizer caused iodine leaching ratesdecreased by49.02%and37.25%. When applying the controlled-release selenium fertilizerand controlled-release iodine-selenium fertilizer in the soil, the soil iodine leaching ratesdecreased by38.91%and46.61%, respectively.更多还原