Iodine Fortification Plant Screening Process and Accumulation in Tomato Fruits and Potato Tubers

Iodine is an essential microelement for human health, and the recommended daily allowance (RDA) of such element should range from 40 to 200 μg day^?1. Because of the low iodine contents in vegetables, cereals, and many other foods, iodine deficiency disorder (IDD) is one of the most widespread nutrient-deficiency diseases in the world. Therefore, investigations of I uptake in plants with the aim of fortifying them can help reach the important health and social objective of IDD elimination. This study was conducted to determine the effects of the absorption of iodine from two different chemical forms—potassium iodide (I^?) and potassium iodate (IO^? ₃)—in a wide range of wild and cultivated plant species. Pot plants were irrigated with different concentrations of I^? or IO^? ₃, namely 0.05% and 0.1% (w/v) I^? and 0.05%, 0.1%, 0.2%, and 0.5% (w/v) IO^? ₃. Inhibiting effects on plant growth were observed after adding these amounts of iodine to the irrigation water. Plants were able to tolerate high levels of iodine as IO^? ₃ better than I^? in the root environment. Among cultivated species, barley (Hordeum vulgare L.) showed the lowest biomass reductions due to iodine toxicity and maize (Zea mays L.) together with tobacco (Nicotiana tabacum L.) showed the greatest. After the screening, cultivated tomato and potato were shown to be good targets for a fortification-rate study among the species screened. When fed with 0.05% iodine salts, potato (Solanum tuberosum L.) tubers and tomato (Solanum lycopersicum L.) fruits absorbed iodine up to 272 and 527 μg/100 g fresh weight (FW) from IO^? ₃ and 1,875 and 3,900 μg/100 g FW from I^?. These uptake levels were well more than the RDA of 150 μg day^?1 for adults. Moreover, the agronomic efficiency of iodine accumulation of potato tubers and tomato fruits was calculated. Both plant organs showed greater accumulation efficiency for given units of iodine from iodide than from iodate. This accumulation efficiency decreased in both potato tubers and tomato fruits at iodine concentrations greater than 0.05% for iodide and at respectively 0.2% and 0.1% for iodate. On the basis of the uptake curve, it was finally possible to calculate the doses of supply in the irrigation water of iodine as iodate (0.028% for potato and 0.014% for tomato) as well as of iodide (0.004% for potato and 0.002% for tomato) to reach the 150 μg day^?1 RDA for adults in 100 g of such vegetables, to efficiently control IDD, although these results still need to be validated.     

用低场核磁共振检测水稻浸种过程中种子水分的相态及分布特征

为研究水稻浸种过程中种子的水分相态及其分布特征,利用低场核磁共振快速、无损、准确的检测技术,通过硬脉冲回波序列CPMG(carr-purcell-meiboom-gill sequence)测量水稻种子横向弛豫时间T2,根据横向弛豫时间T2的差异区分种子内部的水分相态及其变化规律。试验结果表明:通过T2反演谱横向弛豫时间T2长短的差异,发现水稻浸种过程中种子内部水分存在结合水、自由水2种水分状态,同时可区分出内层水、中层水、外层水3种水分分层;二者均能通过回归方程合理的估测水稻在浸种过程中种子的吸水率情况;通过T2反演谱信号幅值大小的差异,发现水稻浸种过程中的种子总水含量不断上升,但由于判定依据及划分方式的不同,二者在水分的流动方式上略显差异。低场核磁共振技术对水稻浸种过程中种子内部的水分变化进行了直观的揭示,提供了一种高效的种子水分检测方法。     

硒碘联合生物营养强化规律及硒碘交互作用初步研究

硒和碘是人体重要的微量元素,硒和碘缺乏可能导致人体处于亚健康状态或患多种疾病。膳食是安全、高效的补充硒和碘的方式。目前,对植物吸收两种元素的相关性研究较为匮乏。本试验通过施加一定含量梯度的碘酸钾、硒酸盐,探究番茄、生菜两种作物对硒和碘的吸收能力,以及两种元素吸收的相关性。研究结果表明:番茄植株相比生菜,对无机硒和碘酸钾的富集能力更强;生菜和番茄中,硒和碘的吸收没有显著相关性。     

结合态与无机态钠对木质素半焦气化特性的影响

采用高温水平管式炉热解制取含有机结合态钠和无机态钠的木质素半焦,利用扫描电镜/能谱分析仪(SEM/EDS)和热重分析仪(TG)对半焦的形貌、元素分布及气化特性进行研究,借助热重红外联用技术(TG-FTIR)考察2种状态钠对木质素半焦气化反应性影响机理。结果表明,随着制焦温度由400℃增加到800℃,结合态钠木质素半焦表面出现大量鼓泡,半焦表面钠元素相对含量由5.36%增加到15.72%,半焦的CO_2和水蒸气气化碳转化率分别增加30%和20%;无机态钠催化木质素实验结果与结合态钠木质素相反。反应温度低于600℃时,结合态钠与木质素半焦反应主要为—CO_2Na与半焦反应;反应温度600~800℃范围内,主要为—CO_2Na和—CONa与半焦反应;当温度高于800℃时,主要为—CONa与半焦反应。     

等壳碾压混凝土重力坝层间抗滑稳定可靠度分析

针对以有限元为基础分析碾压混凝土重力坝层间可靠度其功能函数不能显式表达的特点,采用响应面法、JC法、窄界限法原理相结合的可靠度计算方法。由三维非线性有限元对等壳水电站碾压混凝土重力坝各随机变量分位点值的计算结果,采用抗剪断公式构建该电站非溢流坝段层面的功能函数,求得响应面方程,并应用JC法和窄界限法计算层间单元可靠度指标及层间体系可靠度指标,进一步分析材料的变异系数对体系可靠度的影响。结果表明,φ是影响体系可靠度指标的最敏感因子,碾压各层β值一般为4.16～5.70,层间体系可靠度β'为4.12,满足工程要求。该方法计算效率高,实用性强,用于碾压混凝土重力坝层间抗滑稳定可靠度分析是可行的,值得推广。     

水稻不同需水关键期适宜灌水下限指标研究

在5 m2有底测坑内研究水稻拔节孕穗期和抽穗开花期70%～90%土壤饱和含水率灌水下限对灌溉制度、渗漏量和产量等的影响。结果表明,不同灌水条件下,灌水次数、灌水模数、灌溉定额发生较大变化,灌水次数在本田期为28～37次,灌溉定额为8 190～9 450 m3/hm2,各处理渗漏量随着灌水量的降低而降低,渗漏量为灌水量的54.22%～64.25%,拔节孕穗期较抽穗开花期需水更敏感,拔节孕穗期应保持湿润状态,抽穗开花期适宜灌水下限为90%。     

水稻对水稻土中甲磺隆结合残留的响应

Metsulfuron-methyl is one of the widely used sulfonylurea herbicides. However, approximately half of the applied metsulfuron-methyl may remain as bound residues in soil. To characterize the response of rice plants to residual metsulfuron-methyl in soil, the activities of acetolactate synthase （ALS）, superoxide dismutase （SOD）, peroxidase （POD）, and catalase （CAT） were investigated in two rice varieties that differed in susceptibility to the herbicide. Changes in the activity of these enzymes in leaves and roots of Xiushui 63, a sensitive rice variety, were greater than those in a resistant variety Zhenong 952. Irrespective of variety, changes in the enzyme activity were greater in the roots than in the leaves. The activities of ALS and CAT decreased, while the SOD activity increased with the increase in the amounts of bound residues of metsulfuron-methyl （BRM） in soil. The POD activity increased at the BRM level of 0.025 mg kg^-1, but decreased at the BRM level of 0.05 mg kg^-1. The results showed that the bound residues of sulfonylurea herbicides may affect metabolism of rice plants.     

日粮中高碘对母鸡繁殖性能的影响

在２５周龄母鸡日粮中添加高剂量碘化钾，持续１６周，观察产蛋率，种蛋受精率及孵化率的变化，并用ＲＩＡ法测定鸡血浆中的雌激素、孕酮浓度．结果表明，高碘组母鸡产蛋率下降，种蛋爱精率无明显变化但孵化率降低．母鸡血浆雌激素的基础分泌量无显著变化，但高碘引起孕酮基础分泌量升高，而且导致雌激素、孕酮的周期分泌率紊乱．     

玉米胚原油挤压膨化工艺的优化

螺杆是挤压机的重要组成部分。以挤压机螺杆构型参数阻流环直径、轴头间隙长度、螺杆转速、螺纹升角为试验因素,以浸提玉米胚原油的碘值为考察指标,研究挤压参数对碘值的影响。通过四因素五水平二次正交旋转组合法设计试验,利用SAS9.1软件对试验数据进行响应面分析,得到最佳挤压膨化工艺参数为阻流环直径92 mm、轴头间隙长度16 mm、螺纹升角为7°06′、螺杆转速为180 r/min,在最优参数下碘值为78.56 g/100 g。     

土壤中红霉素结合残留在菜心中生物有效性研究

为探究土壤环境中红霉素污染的生物风险,本试验采用¹⁴C示踪技术,选取广东菜心为代表,研究红霉素结合残留的释放、转化及生物有效性,并探讨添加外源有机肥(如鸡粪、活性淤泥)对该过程的影响。结果表明,土壤中红霉素结合残留随着时间推移逐渐释放,在培养45 d时下降至引入量的59.83%,其中15.00%转化为可提态残留;植物根系的吸收和扰动能促进红霉素结合残留的释放和转化(P <0.05);土壤中的红霉素结合残留能够被广东菜心根部吸收并转运至可食部分,转运系数为0.34,表明红霉素结合残留在菜心体内不易向上运输;放射性自显影图片显示,被植物吸收的¹⁴C-红霉素及其放射性衍生物主要集中在叶片和根部;外源添加有机肥(鸡粪和活性淤泥)处理,一方面可抑制结合残留的释放,增加富啡酸中红霉素结合残留的含量(P<0.05),导致土壤中红霉素污染更持久,另一方面可促进植物对土壤中红霉素残留的吸收;腐殖质分级结果显示,红霉素结合残留主要集中在富啡酸中(87.92%~97.21%),并随着时间推移不断释放。本研究结果为科学评价红霉素的生态安全提供了理论支持。