不同磷水平下施加腐植酸对藜麦生理特性及产量的影响

正通过不同施磷水平下配施腐植酸探究提高藜麦生长及产量的最佳施肥量,为藜麦优质栽培提供理论依据。利用盆栽试验,以"藜麦1号"为研究材料,研究对照(0 g/kg)、低磷(0.1 g/kg)、中磷(0.2 g/kg)、高磷(0.3 g/kg)4个施磷水平下,施加腐植酸对藜麦根系生理指标及产量等的影响。结果表明:藜麦叶片叶绿素含量、根系抗氧化物酶活性及其产量均随施磷量的增加呈现先增加后降低的趋势,且均以中磷水平最佳。施加腐植酸可提     

藜麦在化妆品中的应用前景

本文通过分析藜麦成分与人体皮肤的密切关系,重点突出了藜麦应用于化妆品中的优势。具体优势如下:藜麦蛋白为天然的皮肤营养剂,天然的头发调理剂。藜麦皂甙为天然温和的植物表面活性剂。藜麦籽油是可食用性的油脂,并且与医学美容关系密切。藜麦丰富的矿物质是皮肤的营养调味剂。     

藜麦蛋白泡沫分离工艺的优化及其功能特性分析

在单因素试验的基础上,采用 Box-Behnken 设计对藜麦蛋白的泡沫分离工艺条件进行优化,考察了料液比、装液量、温度和 pH值对藜麦蛋白回收率和富集度的影响,并对藜麦蛋白的亚基分布和功能特性进行了研究。结果表明：优化的工艺条件为: 温度35℃,pH值4.0,装料量260 mL,料液比0.3 mg·mL-1,在此条件下泡沫分离藜麦蛋白,藜麦蛋白的回收率为95.68% ,富集度为7.89;分离得到的藜麦蛋白具有分子量分别为50、32~39、22~23和8~9 kDa 的基本亚基,在60℃条件下,藜麦蛋白的最高持水量为9.733 g/g,最高持油量为5.848 g/g;随着原料与溶剂比例的增加,藜麦蛋白的乳化能力(EC)、乳化稳定性(ES)、起泡能力(FC)和泡沫稳定性(FS)均呈先增大后减小的趋势;其DPPH自由基清除率与剂量呈正相关,在藜麦蛋白浓度为2.5 mg/mL时,对3 mL 0.2 mmol·L-1的DPPH溶液中的DPPH自由基清除率达到(56.01±1.34)%。     

微波消解-ICP-OES法测定藜麦中的微量元素

建立了电感耦合等离子体发射光谱法(ICP-OES)测定藜麦皮、带皮藜麦、去皮藜麦中微量元素含量测定的分析方法。采用HNO3+HCl混合酸为消解体系,用微波消解法对藜麦皮、带皮藜麦、去皮藜麦样品进行前处理,ICP-OES法测定其中Mn、Cu、K、Ca、Fe、Zn、Mg的含量。结果表明:藜麦皮、带皮藜麦、去皮藜麦中含有大量的人体必需的微量元素,藜麦皮中微量元素的含量大于去皮藜麦中的含量。对照GBW08503B-小麦成分分析标准,Mg、K、Ca在带皮藜麦、藜麦皮、去皮藜麦中的含量远远高于其在小麦中的含量,Mn、Fe、Zn的含量与小麦中的接近,而Cu的含量略低于其小麦中的含量。该方法操作简便、准确,可用于藜麦中微量元素含量的测定。     

复合酶协同超声提取藜麦皂苷及其抗氧化性

采用复合酶协同超声提取藜麦种皮皂苷,并对其抗氧化活性进行了测定。以藜麦皂苷的提取率为指标,考察了酶配比m(纤维素酶)∶m(果胶酶)、酶用量、酶解温度、pH、酶解时间对藜麦皂苷提取率的影响,并用响应面法进行了优化。得到最佳工艺条件为:总酶用量(以藜麦种皮质量为基准,下同)为1.5%,酶配比m(纤维素酶)∶m(果胶酶)为3∶2,酶解温度为50.5℃,pH为5.5,酶解时间为0.25 h。在该条件下,藜麦皂苷的提取率较高,达到85.32%;该法对藜麦种皮皂苷的提取率比单一纤维素酶提取率(81.56%)高4.41%,比单一果胶酶提取率(82.20%)高3.66%,比单独超声提取率(73.07%)高16.76%。采用清除1,1-二苯基-2-三硝基苯肼自由基(DPPH·)的能力,分析藜麦皂苷的抗氧化活性,结果表明,藜麦皂苷具有显著的抗氧化活性,且与皂苷的质量浓度呈剂量依赖性。     

藜麦产地的红外光谱鉴别

种植环境差异导致不同产地的藜麦有差异,故对不同产地的藜麦进行区分鉴别对商家、消费者具有重要参考价值。将中红外光谱与主成分分析(PCA)、线性判别分析(LDA)及混淆矩阵结合对不同产地藜麦进行鉴别研究。结果显示:藜麦的红外光谱主要由淀粉、蛋白质和脂质谱峰组成,且在蛋白质和糖类谱峰上有差异。用600~4000 cm^-1范围的原始光谱进行PCA分析,前两个主成分(PC)取得了92%的累计方差贡献率,基于PCA分析生成的PC进行LDA分析,取得了96.25%的分类精度。基于预测结果的混淆矩阵作为综合评价指标,得到PCA-LDA分类模型的精确度、召回率及特异性分别为96.25%、96.59%和99.48%,说明使用PCA-LDA模型可以对藜麦产地进行有效鉴别。研究表明红外光谱结合多元统计分析方法是鉴别藜麦产地的有效方法。     

藜麦产地的红外光谱鉴别

种植环境差异导致不同产地的藜麦有差异,故对不同产地的藜麦进行区分鉴别对商家、消费者具有重要参考价值。将中红外光谱与主成分分析(PCA)、线性判别分析(LDA)及混淆矩阵结合对不同产地藜麦进行鉴别研究。结果显示:藜麦的红外光谱主要由淀粉、蛋白质和脂质谱峰组成,且在蛋白质和糖类谱峰上有差异。用600~4000 cm^-1范围的原始光谱进行PCA分析,前两个主成分(PC)取得了92%的累计方差贡献率,基于PCA分析生成的PC进行LDA分析,取得了96.25%的分类精度。基于预测结果的混淆矩阵作为综合评价指标,得到PCA-LDA分类模型的精确度、召回率及特异性分别为96.25%、96.59%和99.48%,说明使用PCA-LDA模型可以对藜麦产地进行有效鉴别。研究表明红外光谱结合多元统计分析方法是鉴别藜麦产地的有效方法。     

藜麦蛋白提取工艺优化及抗氧化活性研究

研究了藜麦蛋白提取的最佳工艺条件及抗氧化活性。以藜麦种子为原料,通过纤维素酶和糖化酶对其蛋白质进行复合酶解提取。以蛋白质的提取率为考察指标,在单因素试验的基础上,固定酶配比,利用响应面试验进行优化。得到最佳提取条件为:酶配比[m(纤维素酶)∶m(糖化酶)]为4∶6、酶解时间为70. 59 min、酶解温度为50. 06℃、pH为5. 03、总加酶量为427. 18 U/g,通过验证实验得到的蛋白质提取率为76. 82%。在此条件下得到的藜麦蛋白具有清除DPPH自由基、羟自由基的能力,说明藜麦蛋白具有一定的抗氧化活性。     

石墨烯粘胶纤维制备及性能研究

利用短流程Brodie’s氧化还原方法制备石墨烯原料,对制备的石墨烯的形态结构及粒径、石墨烯与粘胶共混纺丝液的性能和石墨烯粘胶纤维的形态结构及功能性进行了分析研究。结果表明:石墨烯的加入对共混纺丝液的性能影响较小,可纺性良好;纺制的石墨烯粘胶纤维可达到相关标准中要求的防紫外线性能、远红外性能、抗菌性能以及抗静电性能,功能性优良。     

SDS表面活性剂在纳米尺度多层石墨烯的吸附自组装分子模拟

采用分子动力学模拟分别研究了纯水和电解质溶液中SDS表面活性剂在纳米尺度石墨烯表面的自组装结构,考察了不同石墨烯层数对自组装吸附形态和SDS/石墨烯复合物悬浮密度的影响。模拟结果揭示了上述两种溶剂介质中,SDS的表面自组装结构形态与石墨烯的结构层数有关,增加石墨烯的层数能够加大吸附表面活性剂向溶液中的伸展程度,使表面活性剂自组装结构膨胀。此外电解质存在能够导致SDS表面活性剂在石墨烯表面吸附形态由多层结构向半圆胶束转化。模拟计算进一步发现SDS/石墨烯超分子复合物的悬浮密度随石墨烯层数的增加呈近似线性增加。     

Morphological and Metabolite Responses of Potatoes under Various Phosphorus Levels and Their Amelioration by Plant Growth-Promoting Rhizobacteria

Low phosphorus (P) availability is a major limiting factor for potatoes. P fertilizer is applied to enhance P availability; however, it may become toxic when plants accumulate at high concentrations. Therefore, it is necessary to gain more knowledge of the morphological and biochemical processes associated with P deficiency and toxicity for potatoes, as well as to explore an alternative approach to ameliorate the P deficiency condition. A comprehensive study was conducted (I) to assess plant morphology, mineral allocation, and metabolites of potatoes in response to P deficiency and toxicity; and (II) to evaluate the potency of plant growth-promoting rhizobacteria (PGPR) in improving plant biomass, P uptake, and metabolites at low P levels. The results revealed a reduction in plant height and biomass by 60–80% under P deficiency compared to P optimum. P deficiency and toxicity conditions also altered the mineral concentration and allocation in plants due to nutrient imbalance. The stress induced by both P deficiency and toxicity was evident from an accumulation of proline and total free amino acids in young leaves and roots. Furthermore, root metabolite profiling revealed that P deficiency reduced sugars by 50–80% and organic acids by 20–90%, but increased amino acids by 1.5–14.8 times. However, the effect of P toxicity on metabolic changes in roots was less pronounced. Under P deficiency, PGPR significantly improved the root and shoot biomass, total root length, and root surface area by 32–45%. This finding suggests the potency of PGPR inoculation to increase potato plant tolerance under P deficiency.     

青蒿毛状根悬浮培养动力学及其计量关系

分析了青蒿毛状根悬浮培养过程中生长、青蒿素合成、底物消耗及电导率变化的动力学,认为毛状根生长和青蒿素合成非偶联,毛状根生物量与电导率之间存在明显的线性关系.计算了生物量对碳、氮源的得率系数,并通过元素分析,建立了毛状根生长的基本计量关系式,从理论上计算出了得率系数及呼吸商.     

Differential Activity of Plasma and Vacuolar Membrane Transporters Contributes to Genotypic Differences in Salinity Tolerance in a Halophyte Species,Chenopodium quinoa

Halophytes species can be used as a highly convenient model system to reveal key ionic and molecular mechanisms that confer salinity tolerance in plants. Earlier, we reported that quinoa (Chenopodium quinoa Willd.), a facultative C3 halophyte species, can efficiently control the activity of slow (SV) and fast (FV) tonoplast channels to match specific growth conditions by ensuring that most of accumulated Na⁺ is safely locked in the vacuole (Bonales-Alatorre et al. (2013) Plant Physiology). This work extends these finding by comparing the properties of tonoplast FV and SV channels in two quinoa genotypes contrasting in their salinity tolerance. The work is complemented by studies of the kinetics of net ion fluxes across the plasma membrane of quinoa leaf mesophyll tissue. Our results suggest that multiple mechanisms contribute towards genotypic differences in salinity tolerance in quinoa. These include: (i) a higher rate of Na⁺ exclusion from leaf mesophyll; (ii) maintenance of low cytosolic Na⁺ levels; (iii) better K⁺ retention in the leaf mesophyll; (iv) a high rate of H⁺ pumping, which increases the ability of mesophyll cells to restore their membrane potential; and (v) the ability to reduce the activity of SV and FV channels under saline conditions. These mechanisms appear to be highly orchestrated, thus enabling the remarkable overall salinity tolerance of quinoa species.     

Spectrophotometric determination of oleanolic acid and saponins from quinoa (Chenopodium quinoa Willd, Kancolla variety)

Saponins were extracted from quinoa (Chenopodium quinoa Willd, Kancolla variety) by refluxing with a methanol-water (4:1) mixture. Once the methanol was evaporated, the remaining residue was treated following Honerlagen and Tretter's method with only slight modifications. The extract was then hydrolyzed with 12N sulfuric acid in a 1:1 dioxane-water system at 110 degrees C for 1.5 hr. The sapogenins were extracted with chloroform, concentrated and some microliters (equivalent to 121 mg of quinoa) were spotted, against an oleanolic acid standard, on a silicagel g plate and developed with a chloroform-acetone-benzene (80:20:10; v/v) mixture. The spots were located by iodine vapor, and the band whose Rf was similar to that of the oleanolic acid, was scraped into a glass column, eluted with chloroform, dried out, dissolved in 1 ml of glacial acetic acid, treated with 4 ml of (1:1; v/v) sulfuric acid:glacial acetic acid mixture, heated in a water bath at 60 degrees C for 25 minutes, cooled and taken to the spectrophotometer where it was read at a wave length of 527 nm against a reagent blank. Under the same conditions, the oleanolic acid employed as a standard showed a linearity in the range of 60 to 480 micrograms. The oleanolic acid percentage has been determined (0.269 +/- 0.025) in quinoa, and the content of saponins estimated using a conversion factor found by gas chromatography and expressed in the following relationship: % Saponin = (8.5204) x (% oleanolic acid) The sapogenin extract obtained - analyzed by this method - showed an error of 10.7% in relation to its gas chromatography determination.     

Cytogenetic analysis of quinoa chromosomes using nanoscale imaging and spectroscopy techniques

Here we present a high-resolution chromosomal spectral map derived from synchrotron-based soft X-ray spectromicroscopy applied to quinoa species. The label-free characterization of quinoa metaphase chromosomes shows that it consists of organized substructures of DNA-protein complex. The analysis of spectra of chromosomes using the scanning transmission X-ray microscope (STXM) and its superposition of the pattern with the atomic force microscopy (AFM) and scanning electron microscopy (SEM) images proves that it is possible to precisely locate the gene loci and the DNA packaging inside the chromosomes. STXM has been successfully used to distinguish and quantify the DNA and protein components inside the quinoa chromosomes by visualizing the interphase at up to 30-nm spatial resolution. Our study represents the successful attempt of non-intrusive interrogation and integrating imaging techniques of chromosomes using synchrotron STXM and AFM techniques. The methodology developed for 3-D imaging of chromosomes with chemical specificity and temporal resolution will allow the nanoscale imaging tools to emerge from scientific research and development into broad practical applications such as gene loci tools and biomarker libraries.     

植物纤维素原料预处理技术的研究进展

对植物纤维素的原料的预处理方法进行了综述,物理方法中,机械粉碎是较常用的方法,但耗能较多;稀酸预处理能有效去除半纤维素,效率较高,但稀酸处理能耗较多且对设备的防腐要求较高;蒸汽爆破处理能有效地分离纤维素、半纤维和木质素,所处理物料酶解转化率高。     

生物质颗粒孔隙结构在热解过程中的变化

利用氮气等温吸附/脱附法（-196℃）和扫描电镜（SEM）等研究了热解过程中生物质颗粒孔隙结构的演化规律,并用分形维数来描述焦颗粒内部孔隙表面形态的复杂程度。结果表明,热解温度对生物质焦的孔结构和表面形态有显著影响。热解过程中孔网络结构在发生演变,孔的形状发生了一定变化,且孔径有先变小后变大的趋势。高温导致焦颗粒发生塑性变形,使得孔隙扩大和孔表面更加光滑。随着温度的升高,生物质焦的BET比表面积先增大后减小,500℃以前,孔容积的变化规律与比表面积相近。通过分形FHH方程回归得到的分形维数能较好地表征颗粒内部孔隙表面的分形特征。其分形特征与热解温度密切相关,分形维数的变化与BET比表面积有一定关联。     

Microwave processing of starch‐based porous structures for tissue engineering scaffolds

A novel microwave (MW) processing technique was used to produce biodegradable scaffolds for tissue engineering from different types of starch‐based polymers. Potato, sweet potato, corn starch, and nonisolated amaranth and quinoa starch were used to produce porous structures. Water and glycerol were used as plasticizers for the different types of starch. Characterization of the pore morphology of the scaffolds was carried out with scanning electron microscopy. Three‐dimensional structures with variable porosity and pore size distribution were obtained with the MW foaming technique. The amount of remaining water in the scaffolds and their corresponding densities showed important variations among the different types of starch. Compressive mechanical properties were assessed by indentation tests, and a strong dependence of the indentation stress on the average pore size was found. Studies in simulated body fluid were used to assess the in vitro bioactivity, degradability, and surface topology evolution in the scaffolds. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1332–1339, 2007