【作者】 张进；

【导师】 吴良欢；

【作者基本信息】 浙江大学 ， 植物营养学， 2007， 博士

【摘要】 缺Fe引起的营养失衡问题是目前世界上人类面临的主要营养健康问题之一。缺Fe严重削弱人体免疫系统功能，阻碍身体正常的生长发育。在我国尤其是中西部地区，因摄入主食作物中Fe含量不足以满足需要而引起的人体营养不良问题普遍存在。因此，提高主食作物及其产品的Fe含量对缓解或消除人体Fe营养不良问题具有重要意义。稻米是重要的粮食作物之一，世界上50％人口以大米为主食，但大米是低Fe、Zn营养食品。因此，稻米中Fe含量的些许提高对改善人体Fe营养缺乏，提高人体健康水平意义重大。在当今讨论的解决人类微量元素缺乏问题的几种策略中，农艺措施尤其施肥已成为改善谷物中微量元素缺乏的一种现实的、经济的和可持续发展的策略，而鉴于微量元素Fe易被土壤固定，根外喷施就成为经济有效的施用方法。但到目前几乎所有的根外喷Fe试验研究主要集中在缓解植物缺Fe失绿症的矫正上，叶面喷施Fe肥能否强化谷类作物籽粒Fe营养方面的研究未见报道。本论文即研究叶面施用Fe肥及田间养分综合管理对水稻籽粒Fe营养的生物强化效应。取得的主要研究结果如下：1．生物强化稻米Fe营养高效叶面肥料—Fe（Ⅱ）-AA的研制。与喷施去离子水（对照）相比，水稻叶面喷施Fe（Ⅱ）-AA，一般能使精米中Fe营养浓度显著提高15％左右，且精米中其他有益中微量元素含量如Ca、Mg、B、Zn、Cu、Mn等均有不同程度的增加，精米蛋白质和氨基酸含量也有明显提高。与常用叶面Fe肥如FeSO₄ 7H₂O和Fe（Ⅲ）-EDTA相比，对稻米Fe营养的生物强化效应及其营养品质的提高效果显著，且避免了Fe²⁺的迅速氧化，价格便宜，便于生产上大面积施用。Fe（Ⅱ）-AA肥效稳定。盆栽及大田喷施试验结果表明，与对照（喷施去离子水）相比，Fe（Ⅱ）-AA处理对不同基因型水稻糙米Fe营养的生物强化效应是显著的。糙米Fe浓度提升最高的是编号429的籼稻，达67.41％，使粳稻“丙98110”精米Fe浓度提高了13％-19％。Fe（Ⅱ）-AA处理对不同基因型稻米Fe营养的生物强化效应明显不同，其对籼型糯性白米稻糙米中Fe的强化在15％以上，对籼型糯性黑米稻编号9088的糙米Fe强化高达38％，对几个籼型非糯性稻糙米Fe的强化在25％左右。2．试验发现，在水稻开花期后喷施Fe（Ⅱ）-AA，与对照（不喷施Fe（Ⅱ）-AA）相比，不仅稻谷产量而且精米中Fe浓度等营养品质指标均有显著提升。在粳稻“丙98110”开花期后喷施Fe（Ⅱ）-AA，稻谷产量达到了13.197 g plant^-1，比对照显著提高了13.96％，精米中Fe浓度显著提高了13.18％，蛋白质和总氨基酸含量也分别显著提高了13.78％和13.63％。而其他两个时期（分蘖期和孕穗期）喷施Fe（Ⅱ）-AA，稻米中Fe营养含量强化效应不显著。因此，综合精米Fe含量、稻谷产量及其营养品质考虑，在水稻开花期后喷施Fe（Ⅱ）-AA对稻米Fe营养的生物强化效应最好，同时也能收到增产提质的效果。3．合理的田间养分综合管理是获得水稻高产、优质的重要途径。盆栽条件下，对N、P、K及其互作效应对稻米Fe营养的生物强化效应进行了探讨，并运用二次多项式回归方程建立了N、P、K互作与稻米Fe营养之间的肥效关系。结果表明，单施氮肥可以强化稻米Fe营养，增加施氮量能提高稻米Fe含量；适量施磷肥能强化稻米中的Fe营养，过量施P不利于稻米中Fe的积累；低钾有利于提高稻米中Fe浓度，过量施钾降低其含量。氮磷钾养分综合管理对稻米Fe营养有强化效应，由回归设计建立氮磷钾肥效应方程：Y=3.22+15.70X₁+14.62X₂-10.26X₁²-8.45X₂²-14.39X₁^*X₂（R=0.86^*）。进一步计算可知，当施尿素1.20 g pot^-1，过磷酸钙0.39 g pot^-1，氯化钾0.53 g pot^-1，得出籼稻“浙农952”糙米中最优Fe浓度为10.180 mg kg^-1。4．叶面喷施Fe²⁺和Fe³⁺的吸收机理研究表明，叶面喷施Fe^Ⅲ-EDTA显著提高了两个水稻品种籼稻“浙农952”和粳稻“丙98110”叶片质膜上的氧化还原系统活性，Fe^Ⅱ-EDTA处理对其没有影响；叶面喷施Fe^Ⅱ-EDTA和Fe^Ⅲ-EDTA均显著提高了两种水稻叶片质膜上的H⁺-ATPase活性。水稻对叶面Fe离子的吸收可能为主要依赖质膜上H⁺-ATPase和氧化还原系统的主动吸收过程。水稻叶片以吸收Fe²⁺为主，Fe³⁺还原为Fe²⁺是叶片吸收的前提。5．对水稻籽粒Fe积累动态的研究表明，水稻花后灌浆过程中，稻米Fe浓度总体呈下降趋势，花后前15天下降趋势非常明显，以后趋缓。而灌浆过程中，稻谷Fe含量总体呈上升趋势，与稻米中Fe浓度相反，花后前15天上升趋势非常明显，以后趋缓。显示水稻进入开花期开始灌浆后尊位时间内稻米碳水化合物卸载量明显高于Fe营养吸收量，但单位稻谷（包括稻壳）内Fe营养的绝对含量缓慢增加。Fe积累与碳水化合物在稻米内的卸载不是同步的，Fe并不是随着光合产物向库（稻谷）的卸载而积累的，暗示稻米Fe积累机制与碳水化合物的卸载机制不同。本试验结果还显示，很大部分的Fe营养向稻米中的积累发生在水稻进入开花期后的前15天内，碳水化合物的卸载发生在前20天内。这表明如果通过外部手段如叶面喷施肥料等农艺措施调控稻米Fe营养水平，最佳时期可能是在水稻进入开花期后的前15-20天，这与我们有关“开花期后喷施Fe（Ⅱ）-AA对稻米Fe营养的生物强化效应最好，同时也能收到增产提质的效果”的试验研究结果是一致的。更多还原

【Abstract】 Iron （Fe） deficiency is widespread in the world, especially in developingcountries, where it is estimated that 40-45% of school-age children are anemic,approximately 50% of this anemia results from Fe deficiency. And in China, about20% of the people are influenced by Fe deficiency. Fe deficiency will weakenimmune function and impair growth and development. A major etiologic factor is thelow concentration of Fe from diets based on the staple cereals.Half of the world’s population ate rice （Oryza sativa L.） daily and depended on itas their staple food. It provides 23%, which is more than wheat and corn, of all thecalories consumed by the world’s population, and even provides 50-80% of theenergy intake of the people in the developing countries. Rice, however, is a poorsource of many essential micronutrients, especially of Fe for human nutrition.Malnutrition of Fe afflicts more than 50% of the world’s population at present. Heavyand monotonous consumption of rice with low concentrations of Fe has beenconsidered a major reason. Therefore, even a slightly increase in its nutritive valuewould be highly profound for alleviation of malnutrition, and then would be greatbeneficial for human health.In several potential approaches discussed and processed to increase Feconcentration of rice grains, the fertilization via soils and foliar applications could bea more sustainable, low cost-effective and high efficient strategy. So in the paper, thedevelopment of a new high efficient Fe foliar fertilizer and its role on ironbiofortification in rice grians and also with regulation of intergrated nutrientmanagement in soil-crop system were discussed. The main results are summarized asfollows:Development of Fe（Ⅱ）-AA, a new high efficient Fe foliar fertilizer, for ironbiofortification of rice grians. With foliar spray of Fe（Ⅱ）-AA, iron dense in ricegrains will be enhanced significantly not less than 15% compared to foliar spray ofdeioned water, and other mineral nutrients in rice grains such as Ca, Mg, B, Zn, Cu,Mn are also increased markedly, and also protein and amino acids of rice areimproved. Compared to other iron fertilizer commonly adopted for foliar application,e. g. FeSO₄ 7H₂O and Fe（Ⅲ）-EDTA, the effectiveness of Fe（Ⅱ）-AA on ironbiofortification of rice grains together with improvement of rice nutritional qualtity ispreponderant. Fe²⁺ in Fe（Ⅱ）-AA is not as easily oxidated as FeSO₄ 7H₂O forchelation of Fe²⁺ with amino acids, and the price is less than Fe（Ⅲ）-EDTA, so it issuitable dominantly for field application.The effectiveness of Fe（Ⅱ）-AA on rice iron biofortification is stable. Withexperiments under pot and field conditions, iron biofortification of rice grains issignificant with treatment of foliar Fe（Ⅱ）-AA spray on different rice genotypescompared to foliar deioned water application. The most increase of rice iron dense ishappened on the indica rice numbered 429, which is enhanced by 67.41%. And on thejaponica rice ’Bing 98110’, which is about 15%. Iron biofortification is more than 15% with treatment of foliar Fe（Ⅱ）-AA spray on the white sticky indica rice, andabout 38% on black sticky indica rice, and about 25% on non-sticky indiea rice.In the present study, compared to no Fe（Ⅱ）-AA foliar spray （CK）, iron dense ofrice grains is biofortified significantly with foliar Fe（Ⅱ）-AA spray as well as grainyield in anthesis. For the japonica ’Bing 98110’, grain yield is reached to 13.197 gplant^-1with foliar spray of Fe（Ⅱ）-AA in anthesis, which is increased significantly by13.96% compared to CK. And iron dense in polished rice is enhanced significantly by13.18%, also protein and amino acids in rice are improved notably by 13.78% and13.63% respectively. However, in tiller stage and grain-forming stage of rice, irondense can not be biofortified significantly with foliar Fe（Ⅱ）-AA spray.The rational intergrated nutrient management is one of important approaches toharvesting good nutritional quality and high grain yield on rice production. Under potconditions, the effects of N, P, K fertilization on rice iron biofortification is studied,and the relationship between them is established with the quadratic polynomialregression equation, Y=3.22+15.70X₁+14.62X₂-10.26X₁²-8.45X₂²-14.39X₁*X₂（R=0.86^*）. High iron dense rice production would be guided on fertilization withthe simulation equation.Iron dense could be increased by N fertilization alone, and more ironconcentration could be obtained with more N application. Proper P supply couldincrease rice iron concentration, but P overfeeding would be adverse to iron dense inrice grains. Similarly, low K application could increase rice iron concentration, andhigh K fertilization would decrease iron concentration of rice grains.The absorption mechanism of Fe²⁺ and Fe³⁺ through foliar spray is studied. Theresults are shown that the activities of the plasma membrane redox system on leavesof the two rice varieties ’Zhenong 952’ and ’Bing98110’ are enhanced significantlywith foliar Fe^Ⅲ-EDTA spray, however, Fe^Ⅱ-EDTA has no effect on the redox system.The activities of the plasma membrane H⁺-ATPase on leaves of ’Zhenong 952’and ’Bing98110’ are enhanced significantly with foliar Fe^Ⅲ-EDTA and Fe^Ⅱ-EDTAspray. That suggests leaf iron absorption is an active absorption process depended onthe plasma membrane H⁺-ATPase and redox system. Fe²⁺ is the main form absorbedby rice leaf, Fe³⁺ reduction is prerequisite before its aborption.Iron accumulation trend in rice grains on grain filling stage of rice crops is alsostudied. The results show that in anthesis when grain fill is ongoing the tendency ofiron concentration (mg Fe kg^-1 dry matter) in grains is down, first 20 days afteranthesis the downtrend is evident and then slow. Adverse to iron dense in grains, ironcontent (ug Fe grain^-1) in grains is up, first 20 days after anthesis the uptrend isevident and then slow. That suggests the speed of iron accumulation in grains per timeis lower markedly than downloads of the carbohydrate, but the content of iron pergrain is certainly increased slowly.Generally, iron concentration decreased initially even though their rate ofaccumulation was highest during this time. Iron accumulation and dry matter download in rice grains are not synchronous which show the machnism of iron andthe carbohydrate uptake by grains is different. The majority of uptake of iron and drymatter occurred within the first 20 days after anthesis which suggest if agronomicapproach, especially foliar iron fertilization, is intended to regulation on ironbiofortification of rice grains in rice production the optimum stage on rice cropsshould be first 20 days after anthesis.更多还原