近红外光谱的玉米种子穗腐病特征提取与判别模型研究

玉米种子穗腐病是危害玉米产量的主要病害之一。利用近红外光谱开展了玉米种子穗腐病判别模型研究。246粒玉米种子由吉林省农业科学院海南育种基地提供,其中96粒玉米种子为穗腐病染病样本,其他150粒玉米种子为同种玉米正常样本。利用MATRIX-Ⅰ型傅里叶近红外光谱仪采集了样本800～2 500 nm范围的近红外光谱信息,并对样本近红外光谱数据利用多元散射校正（MSC）进行预处理。结合玉米内部有机物质的近红外光谱的敏感波段和样本近红外光谱吸收峰挑选了4个优选区间,并采用相关系数法(CA)、连续投影算法（SPA）和竞争性自适应重加权算法（CARS）三种不同原理的特征波长提取算法分别提取了4（1 362,1 760,2 143和2 311 nm）、5（1 227,1 310,1 382,1 450和1 728 nm）和10（1 232,1 233,1 257,1 279,1 313,1 688,1 703,1 705,2 302和2 323 nm）个特征波长。以提取得到的特征波长作为玉米种子穗腐病判别模型输入变量,用0-1（染病-正常）表示样本染病状况作为输出真实值建立支持向量机（SVM）模型,使用网格搜索法结合十折交叉验证法对模型参数进行优化。结果表明,CA-SVM,SPA-SVM和CARS-SVM三种判别模型中训练集和测试集建模准确率均在90%以上。该研究成果为玉米种子病害诊断装置提供了模型基础,且针对优选区间进行特征波长选择的方式也可以为建立其他种子病害判别模型提供参考。     

Relationships between Nitrogen Translocation and Accumulation in Growing Plant Parts of Grain Legumes

Abstract

Grain legumes absorbed mineral ¹⁵N at every stage of development and transported it directedly (just as symbiotically fixed ¹⁵N₂) into the plant parts growing at the respective stage. The ¹⁵N accumulation in the grains after long-lasting ¹⁵N supply can be ascribed, for the major part, to a secondary ¹⁵N translocation after a temporary incorporation into older plant parts (leaves, stem). Inhibition experiments with antibiotics revealed no direct relation between the accumulation of amino acid ¹⁵N in growing pods and seeds and the protein synthesis in this target organs. It may include, however, processes of (active ?) uptake and transport with a possible contribution of carrier systems specific for distinct amino acids.     

Synthesis of a Au‐on‐Pd Heteronanostructure Stabilized by Citrate and its Catalytic Application

The preparation of Au‐on‐Pd heteronanostructure (HNS) using citrate‐stabilized polycrystalline Pd nanoparticles (NPs) as the seeds is described. The resulting Au‐on‐Pd HNS is characterized and it is found that the formation of Au‐on‐Pd HNS depends greatly on a ratio between Pd seeds and AuCl₄^? ions added and the optimal molar ratio is 10:1. If fewer AuCl₄^? ions are added (Pd/Au ratio is 100:1), the growth of Au NPs only occurs on part of the Pd seeds’ surface. The addition of more AuCl₄^? ions (Pd/Au ratio is 5:1) hinders the growth of Au NPs on the Pd seeds’ surface. To demonstrate the catalytic performance, the electrochemistry oxidation of ethanol and the reduction of p‐nitrophenol by NaBH₄ are chosen to examine the catalytic activity of Au‐on‐Pd HNS. Pd seeds, Au NPs, and poly(vinyl pyrrolidone) (PVP)‐stabilized PdAu nanoalloy are used as the references for comparison. In the first reaction, the catalytic reactivity of Au‐on‐Pd HNS is better than that of corresponding pure Pd or Au NPs, while the opposite occurs for the latter reaction. The catalytic activity of Au‐on‐Pd HNS is much higher than that of PVP‐stabilized PdAu nanoalloy.     

可见-近红外多光谱数据对水稻种子成活率的判定

种子活性受到存储条件的影响很大。收集了真实情况下受到不同存储条件影响的种子,通过发芽实验验证了其成活率存在差异。再从中选择适量的种子样本,采集其单颗种子的可见-近红外反射光谱,运用不同的光谱预处理技术,结合不同的机器学习建模手段,以区分不同成活率的种子。比较了不同的光谱预处理方法,比如标准反射光谱校正、多元散射校正等。从识别准确度的角度,认为标准反射光谱校正的方法,能够很大程度上提升不同存活率种子的光谱差异性,从而经过机器学习判断达到更高的识别准确度。同时比较了支持向量机、 K邻近和距离判别分析等机器监督学习建模方法,发现利用标准反射光谱校正的方法结合距离判别分析,能够对种子样本实现完全准确的判定。更进一步,为了满足实际运用中快速识别的要求,将高分辨率的光谱数据压缩成为低分辨率多通道带通光谱数据,这样可以大大降低的光谱数据长度,节约各种机器学习器在训练和判断中所用的时间。使用简化过后的多通道带通光谱数据判定种子存活率,其识别准确度仍然接近90%。充分说明了,利用多通道宽带光谱数据,并选择合适的机器学习建模方式,足以满足实际选种产业的一般性需求,有潜力作为未来粮种成活率快速鉴别的技术手段。还采用了多种带通宽度以简化光谱,分析比较不同带通宽度对识别精度的影响。总体来说由于带宽增大,数据量减少,识别速度更快,但是识别精度降低。从10~50 nm改变光谱带宽,标准反射校正后的简化光谱的识别精度从87.50%下降到58.75%。在实际运用中,需要权衡识别速率和预期识别精度,合理的选择带宽。验证了根据简化后的可见近红外反射光谱,能够较快速且准确的识别水稻种子存活率,为以后的基于带通滤波片的快速种子存活率识别奠定了基础。     

Die Lagerung von radioaktiven Stoffen

P³² and C¹⁴ have been used together to identify and tgrace the photosynthates of Zea mays during the seedling stage. By this double labelling technique and single labelling with C¹⁴O₂ and H₃P³²O₄, carbohydrates, amino acids, and phosphoproteins were identified on paper chromatograms. Tables and figures summarise the results obtained under different mineral deficiency. These results indicate the effects of the absence of P, Mg, K, N, Ca, and trace elements on both respiration and photosynthesis.     

Purification of the total steroidal saponins from fenugreek seeds (Trigonella foenum-graecum L.) using aqueous two-phase system and determination of diosgenin content using micellar electrokinetic chromatography method

The total steroidal saponins, particularly its major steroidal sapogenin (diosgenin), are the main active principles of fenugreek seed extract. In this study, an ethanol-salt aqueous two-phase system (ATPS) was explored for the purification of the total steroidal saponins, and the process conditions were optimized by response surface methodology (RSM). Under the optimized conditions, the RSM predicted recovery of the total steroidal saponins in the top phase of ATPS was 97.9%, which agreed with the average experimental recovery (98.3 ± 4.2% (n = 6)). Moreover, a rapid micellar electrokinetic chromatography (MEKC) method was developed for the determination of diosgenin from extracts. The diosgenin content in the ATPS top phase extract was 3-fold higher than that in crude extract, suggesting this ATPS having a great potential for purification pharmacological active ingredients from fenugreek seeds.     

The use of fast field cycling to evaluate the time domain relaxation of starches from tropical fruit seeds

ABSTRACT

A proton NMR relaxation study of the molecular dynamics in flour samples of ‘Eugenia uniflora’ (‘Pitanga’), ’Citrus reticulate’ (‘Tangerine’), ‘Prunus persica’ (‘Peach’), ‘Vitis vinifera’ (‘Grape’), and ‘Cucumis melo’ (‘Honeydew melon’) seeds is presented. The spin–lattice relaxation time was obtained over a broad frequency range from 100?kHz to 100?MHz using both conventional and fast field-cycling NMR techniques. This relaxometry study made possible a comparison between the molecular dynamics behaviour of starch from different fruit seeds and from potatoes. I was possible to conclude that the spin–lattice dispersion presents slightly differences for all samples, in particular at low frequencies. All relaxation dispersions could be well interpreted in terms of power-law relaxation models and domains with different power-law relaxation exponents. For the Peach seeds flour the relaxation dispersion at low frequencies was very similar to that observed for potato’s starch incorporated with 5% organoclay Viscogel B8 nanoparticles.     

自然老化谷类种子的二维红外光谱研究

种粮老化影响种子活力及粮食品质。利用傅里叶变换红外光谱(FT-IR),二阶导数红外光谱(SD-IR)和二维相关红外光谱(2D-IR)方法对不同储藏年份的大麦,小麦,稻谷,玉米和高粱种子进行区分研究。结果显示,原始光谱中几个峰强比有差异;在二阶导数红外光谱中,不同储藏年份种子在1 800～800 cm-1范围内的吸收峰强度和形状显示出差异。二维相关红外光谱结果显示：大麦在1 350～1 800 cm-1,小麦,稻谷,玉米和高粱在860～1 690 cm-1范围内有明显差异,随储藏年份增加,自动峰和交叉峰的数目减少,强度减弱。结果表明,应用傅里叶变换红外光谱结合二维相关红外光谱能有效快速地区分不同储藏年份的谷类种子。     

Ferromagnetic seeding for the magnetic targeting of drugs and radiation in capillary beds

A new implant assisted-magnetic drug targeting approach is introduced and theoretically analyzed to demonstrate its feasibility. This approach uses ferromagnetic particles as seeds for collecting magnetic drug carrier particles at the desired site in the body, such as in a capillary bed near a tumor. Based on the capture cross section (λ_c) approach, a parametric study was carried out using a 2-D mathematical model to reveal the effects of the magnetic field strength (μ₀H₀=0.01–1.0 T), magnetic drug carrier particle radius (R_p=20–500 nm), magnetic drug carrier particle ferromagnetic material content (x_fm,p=20–80 wt%), average blood velocity (u_B=0.05–1.0 cm/s), seed radius (R_s=100–2000 nm), number of seeds (N_s=1–8), seed separation (h=0–8R_s), and magnetic drug carrier particle and seed ferromagnetic material saturation magnetizations (iron, SS 409, magnetite, and SS 304) on the performance of the system. Increasing the magnetic field strength, magnetic drug carrier particle size, seed size, magnetic drug carrier particle ferromagnetic material content, or magnetic drug carrier particle or seed saturation magnetization, all positively and significantly affected λ_c, while increasing the average blood velocity adversely affected it. Increasing the number of seeds or decreasing the seed separation, with both causing less significant increases in λ_c, verified that cooperative magnetic effects exist between the seeds that enhance the performance. Overall, these theoretical results were encouraging as they showed the viability of this minimally invasive, implant assisted-magnetic drug targeting approach for targeting drugs or radiation in capillary beds.