不同调制工艺对烘烤过程中烟叶致香物质的影响

为研究烟叶致香物质在烘烤过程中的变化,提高致香物质含量,以‘K326’为材料,研究了4种调制工艺（A香气前体物质中度转化、致香物质中度积累型,B香气前体物质中度转化、致香物质高度积累型,C香气前体物质深度转化、致香物质中度积累型,D香气前体物质深度转化、致香物质高度积累型）对烘烤过程中烟叶致香物质含量的影响。结果表明,下部和中部烟叶致香物质含量最高值出现在烘烤过程的后期阶段,上部烟叶致香物质含量最高值出现在烘烤的前期阶段。下部烟叶采用D调制工艺可以减少致香物质的损失,采用A调制工艺烘烤结束时致香物质含量最高;中部烟叶采用B调制工艺可以减少致香物质的损失,且烘烤结束时致香物质含量最高;上部烟叶采用A调制工艺可以减少致香物质的损失,采用C调制工艺烘烤结束时致香物质含量最高。     

采收时间对烤烟烟叶中性致香物质和感官质量的影响

采用烤箱对成熟度一致的烤烟烟叶进行烘烤,通过对不同采收时间的烤烟烟叶中性致香物质含量和感官质量的分析,对烤烟烟叶成熟采收的外观标准进行量化,以期寻找能够提高香气质、量的烤烟成熟外观标准,为烤烟生产提供理论支撑。结果表明：各部位烟叶外观标准为：下部叶在移栽后60-65d,叶龄在45-50d,叶尖微黄,主脉1/3-1/2、支脉3-5对变白,叶片下垂程度达到1.19-1.20,茎叶夹角70°-75°;中部叶推迟到移栽后95d,叶龄达在65d,叶面黄中带青,主脉2/3以上、支脉8-9对变白,叶片下垂达到1.30,茎叶夹角70°,有成熟斑和焦尖现象;上部叶在115d后采收的烟叶,叶龄在75d以上,叶面几乎全黄,主支脉全白,叶面下垂程度达到1.54以上,茎叶夹角达到75°,有成熟斑和焦尖现象。达到此成熟标准时采收,烤后烟叶中性致香物质含量较高,感官质量评价得分较高,香气质较好,香气量较足。     

云南与津巴布韦烤烟致香物质含量差异研究

【研究目的】为明确云南与津巴布韦烤烟在致香物质方面的差距，指导云南部分替代进口烤烟的研究和生产，提高烟叶质量，特进行此项试验。【方法】采用比色法测定了烟叶多酚总量，索式提取法测定石油醚提取物，硫酸甲酯、三氯甲烷萃取法测定多元酸和高级脂肪酸，水蒸汽-二氯甲烷同时蒸馏萃取、GC/MS-内标定量检测挥发性香气物质；并分类分析比较了云南与津巴布韦烤烟的多酚总量、石油醚提取物、多元酸、高级脂肪酸及挥发性香气物质等烟草致香物质含量的差异。【结果】结果表明云南烤烟各部位烟叶的石油醚提取物、芳香氨基酸降解的香气物质超过津巴布韦烤烟，多酚、高级脂肪酸则低于津巴布韦烤烟；上部烟叶的西柏烷类香气物质高于津巴布韦烤烟，多元酸、类胡萝卜素降解的香气物质、梅拉德反应的香气物质则低于津巴布韦烤烟；中部和下部烟叶的多元酸、类胡萝卜素降解的香气物质、梅拉德反应的香气物质高于津巴布韦烤烟，而西柏烷类香气物质则低于津巴布韦烤烟。云南与津巴布韦烤烟在致香物质方面的差距，主要表现在上部烟叶的柠檬酸、油酸、巨豆三烯酮、金合欢基丙酮、β-二氢大马酮、二氢猕猴桃内酯、糠醇、糠醛等致香物质含量低于津巴布韦烟叶。【结论】云南与津巴布韦烤烟的致香物质差异比较明显，上部烟叶致香物质含量明显不如津巴布韦。     

白肋烟不同叶位叶片中性香气成分和生物碱含量的变化

以白肋烟达白1号非烟碱转化株为材料,在2种留叶数（每株18,24片）条件下研究了不同叶位叶片晾制后生物碱和中性香气成分含量的变化。结果表明,烟碱和仲胺类生物碱含量均随叶位增高而增加,少留叶烟株不同部位生物碱含量均高于多留叶烟株,且上下部位间变幅相对较小。中性香气成分含量呈现不同变化趋势,少留叶烟株各叶位巨豆三烯酮含量高于多留叶烟株,且表现为随叶位升高而增加,多留叶烟株巨豆三烯酮含量以中部叶最高,上部叶含量呈显著降低。其他质体色素降解产物,除β-大马酮含量以中部及偏下部位烟叶较高外,一般表现为随叶位升高而增加。西柏烷类降解产物茄酮含量以中部叶含量较高,多留叶烟株各部位叶片,特别是上部叶茄酮含量高于少留叶烟株。苯丙氨酸降解产物苯乙醛和苯乙醇含量随叶位升高而显著增加。     

氮用量对烟叶质体色素及中性香气基础物质的影响

质体色素及中性香气基础物质是影响烤烟香气质量的重要因素。为了采取合理的氮肥调控措施提高烤烟香气质量,研究了不同氮用量条件下8306和K326两个烤烟基因型叶片质体色素及中性香气基础物质的变化,结果表明:烟草鲜烟叶叶绿素和类胡萝卜素含量随氮用量增加而增加,随烟草生育期推进而减少,与K326相比,高香气基因型8306叶片叶绿素含量较低,而类胡萝卜素含量较高。不同基因型烤后烟叶中性香气基础物质总量,随氮用量增加8306的含量升高,K326的含量降低,在基因型间则表现为8306的含量高于K326的含量。8306和K326两个烤烟基因型,成熟期鲜烟叶类胡萝卜素含量与烤后烟类胡萝卜素降解产物呈极显著正相关关系。     

有机初烤烟叶中性致香物质特征分析

采用同时蒸馏萃取法、内标法和气相色谱—质谱联用法(GC/MS)技术,以常规烟叶作对照,研究了有机初烤烟叶中性致香物质组分及其含量.结果表明:有机烟叶和常规烟叶中性致香物质的种类基本相同,但含量却有较大差异,且部位间也有明显的差异,在所测定的28种主要中性致香物质中,总量均表现为上部叶＞下部叶＞中部叶;有机烟叶除上部叶中苯丙氨酸类致香物质略低于常规烟叶外,类胡萝卜素类、类西柏烷类、棕色化产物类致香物质和中性致香物质总量在3个部位均高于有机烟叶,其中,以中部叶提高幅度最大.     

湖南与河南烤烟烟叶中挥发性致香物质的对比分析

[目的]将湖南与河南两省烤烟中的中性香气成分的含量进行对比,以明确两省烤烟在致香物质方面的差异,从而为探讨两省卷烟风格差异的形成原因提供一定的依据。[方法] 采用美国HP5890Ⅱ-5972气质联用仪定性、内标定量法。[结果]结果表明,在所测出的中性致香成分中,湖南B2F烤烟质体色素类,美拉德反应产物等香气物质总量均比河南烤烟高,而湖南C3F烤烟中的新植二烯,美拉德反应产物和苯丙氨酸类香气物质总量却低于河南同等级烤烟。[结论]湖南与河南烤烟的中性致香物质差异比较明显,河南烟叶致香物质总量明显低于湖南。     

南雄烟区主栽烤烟品种成熟期丙二醛含量变化规律研究

通过对南雄烟区不同烤烟品种成熟过程中活体、离体烟叶丙二醛含量及其变化规律分析,揭示不同烤烟品种烟叶的成熟度与丙二醛含量及其变化的规律相关性差异。结果表明:(1)大田状态下,上部烟叶,‘K326’丙二醛含量随时间呈"S"型变化,‘粤烟97’、‘粤烟98’丙二醛含量随时间呈类指数型变化,采收时MDA含量分别为21.35、18.75、20.59μmol/g;中部叶,3个烤烟品种均呈类指数型变化,采收时烟叶MDA含量为19.74、12.55、12.98μmol/g。(2)离体状态下,上部烟叶,‘K326’丙二醛含量随时间呈类指数型变化,‘粤烟97’和‘粤烟98’呈"S"型变化;中部烟叶,3个烤烟品种均呈"S"型变化。(3)离体烟叶MDA含量在短时间内达到大田状态下成熟采收时的含量水平,而离体后上、中部烟叶MDA含量均呈现"S"型变化趋势,当达到采收值时正好处于离体烟叶"S"型变化趋势的拐点,即离体烟叶MDA含量变化到达拐点之前与大田状态下MDA含量的变化趋势一致。研究表明不同烤烟品种在烤烟成熟过程中丙二醛含量及其变化规律可以指示其成熟度。     

烟草对氮吸收利用的研究

本文采用＾１５Ｎ示踪研究烟草对氮的吸收分布，结果表明烟草的积累量中部叶片＞上部叶片＞下部叶片，而全氮、蛋白态氮、烟碱氮的相对含量均呈上部叶＞中部吉＞下部叶的规律；无论全氮含量还是含氮化合物，它们与其中肥料氮组成比例间的关系都有一致的表现。     

烤烟品种‘K326’不同部位适宜成熟度采收研究

采用田间试验研究了烤烟‘K326’ 品种不同部位成熟采收的标准。结果表明,烤烟品种‘K326’下部叶在5成熟时采收表现较好,香气量足,浓度高,杂气和刺激性均较小;中部叶8成采收,烘烤质量最好,颜色鲜亮、油分多,单叶重较重;上部叶在9成黄时采收的表现最好,香气量足,杂气和刺激性均低。试验结果对烤烟品种‘K326’的种植及提高其产质量具有重要意义。     

Location of a high-lysine gene and the DDT-resistance gene on barley chromosome 7

Summary The high-lysine gene in Risø mutant 1508 conditions an increased lysine content in the endosperm via a changed protein composition, a decreased seed size, and several other characters of the seed. The designation lys3a, lys3b, and lys3c, is proposed for the allelic high-lysine genes in three Risø mutants, nos 1508, 18, and 19. Linkage studies with translocations locate the lys3 locus in the centromere region of chromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker loci fs (fragile stem), s (short rachilla hairs), and r (smooth awn) show that the order of the five loci on chromosome 7 from the long to the short chromosome arm is r, s, fs, lys3, ddt. The distance from locus r to locus ddt is about 100 centimorgans.     

Biological Activity and Quantification of Suspected Allelochemicals from Alfalfa Plant Parts

Autotoxicity restricts reseeding of alfalfa (Medicago sativa L.) after alfalfa until autotoxic chemical(s) breaks down or is dispersed into external environments. A series of aqueous extracts from leaves, stems, roots and seeds of alfalfa ‘Vernal’ were bioassayed against alfalfa seedlings of the same cultivar to determine their autotoxicity. The highest inhibition was found in the extracts from the leaves. Extracts at 40 g dry tissue l^?1 from alfalfa leaves were 15.4, 17.5 and 28.7 times more toxic to alfalfa root growth than were those from roots, stems and seeds, respectively. A high‐performance liquid chromatography (HPLC) analysis with nine standard compounds showed that the concentrations and compositions of allelopathic compounds depended on the plant parts. In leaf extracts that showed the most inhibitory effect on root growth, the highest amounts of allelochemicals were detected. Among nine phenolic compounds assayed for their phytotoxicity on root growth of alfalfa, coumarin, trans‐cinnamic acid and o‐coumaric acid at 10^?3 m were most inhibitory. The type and amount of causative allelochemicals found in alfalfa plant parts were highly correlated with the results of the bioassay, indicating that the autotoxic effects of alfalfa plant parts significantly differed.     

Simultaneous Determination of Four Phenolic Acids in Radix Salviae Miltiorrhizae Formula Granules by QAMS

[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol...     

Changes in Seed Yield and Quality with Maturity in Onion (Allium cepa L., cv. 'Early Cream Gold')

Development of onion (Allium cepa L., cv. ‘Early Cream Gold’) seed under cool climate conditions in Tasmania, Australia occurred over a longer duration than previously reported, but similar patterns of change in yield components were recorded. In contrast to previous studies, umbel moisture content declined from 85 to 67 % over 57 days while seed moisture content decreased from 85 to 31 %. Seed yield continued to increase over the duration of crop development, with increasing seed weight compensating for seed loss resulting from capsule dehiscence in the later stages of maturation. Germination percentage was high and did not vary significantly from 53 to 77 days after full bloom (DAF), but mean germination time declined and uniformity of germination increased significantly over the same time period. The percentage abnormal seedlings declined with later harvest date, resulting in highest seed quality at 77 DAF. The results of this study suggest that the decision to harvest cool climate onion seed crops before capsule dehiscence will result in a loss of potential seed yield and quality.     

Pollen and pollination experiments. III. The viability of apple and pear pollen as affected by irradiation and storage

Summary Apple and pear pollen was irradiated with doses of 0, 50, 100, 250 and 500 krad (gamma rays) and stored at 4°C and 0–10% r.h. From the in-vitro germination percentages an average LD 50 dose of about 220 krad was estimated. For both irradiated and untreated pollen a close and corresponding lineair relationship existed between germination percentage and pollen tube growth.Irradiated pollen was much more sensitive to dry storage conditions than untreated pollen, resulting in less germination and more bursting. Apparently, irradiation caused the pollen cell membrane to lose its flexibility faster than normal. Rehydration of dry-stored, irradiated pollen in water-saturated air restored germination percentages up to their initial levels. The importance of this procedure in germination trials is stressed.     

Evolution under domestication involving disturbance of genic balance

Summary An hypothesis is developed that the rapid change from wild plants into domesticated crops principally involves the selection of alleles with non-functional gene products which leads to reduced control of the highly integrated metabolism and morphogenesis previously accumulated by lengthy natural selection. Such disturbance of the genome produces altered physiological and morphological development which, although deleterious in nature, serves mankind better and has been selected.     

Genetic variation for disease and nematode resistances and forage quality in perennial diploid and tetraploid lucerne populations (Medicago sativa L.)

Summary Twenty-five lucerne populations of the Medicago sativa complex, which were either diploid or tetraploid and wild or cultivated, were analysed for their resistance to four different fungal diseases and to stem nematode. Forage quality, including stem digestibility and saponin content, was also tested.Populations varied in susceptibility to the diseases caused by Colletotrichum trifolii, Verticillium albo-atrum, Sclerotinia trifoliorum and Pseudopezizza medicaginis, and to the nematode Ditylenchus dipsaci. Except for Sclerotinia rot, sativa and falcata subspecies differed in susceptibility, but this grouping of populations did not account for the full range of variation among them. However, the resistance to P. medicaginis was much lower in the sativa than in the falcata populations.Populations also varied significantly in stem fiber content and digestibility. Stem digestibility was negatively correlated to forage yield. Wild sativa and falcata populations had lower fiber content and higher digestibility than cultivated sativa populations. The medicagenic acid was the sapogenin responsible for the anti-nutritional effect of the lucerne measured by the yellow mealworm larvae Tenebrio molitor. The medicagenic acid content was lowest for the pure sativa populations, highest for the pure falcata populations, and intermediate for the French sativa varieties that have some traits originating from falcata germplasm. Some populations could be used in breeding programs to improve disease and nematode resistance, and forage quality.     

Review of Effects of Active Components of Gastrodiae Rhizoma on Central Nervous System

In order to explore the pharmacological effects of active components of Gastrodiae Rhizoma on the central nervous system,through consulting related literatures,...     

Effects of Pb on Rhizosphere Soil Enzyme Activity and Chemical Constituents of Achyranthes bidentata Blume

[Objectives]The purpose of this study was to investigate the effects of Pb on rhizosphere soil enzyme activity and chemical constituents of Achyranthes bidentat...     

不同P-Zn配比对小麦幼苗微量元素营养的影响

采用了螯合-缓冲营养液培养方法对小麦进行了苗期培养试验,在3个P水平(0,0.6,3.0 mmol/L)和3个Zn水平(0,3,30 μmol/L)的完全组合下对小麦苗期生长及Zn、Fe、Cu、Mn营养进行了研究,旨在为小麦微肥施用提供理论依据.结果表明,P、Zn的正常供应促进了小麦生长,二者的缺乏与过量均会抑制小麦发育,且这种影响在冠部表现得更为明显.在小麦苗期,Zn与Cu的吸收存在明显的拮抗作用,但供Zn则促进了Zn和Cu的转运,而Mn转运则受到了抑制;过量供Zn时,大量Zn被转运到冠部,同时明显抑制了(Fe+Cu+Mn)的吸收总量;P的供应显著地抑制了Fe的吸收,但P的供应提高了Zn、Cu、Mn的转运率;P、Zn在对Zn与Fe、Cu、Mn间吸收竞争的影响中,Zn本身的影响要比P的影响更为明显,供Zn明显促进了小麦幼苗对Zn的吸收;在小麦幼苗冠部,Zn与Fe的竞争中,供P利于Zn的吸收,缺P则利于Fe的吸收;而Zn与Cu以及Zn与Mn间的竞争中,缺磷时利于Zn的吸收,供磷后则利于Cu和Mn的吸收.总之,小麦幼苗Zn、Fe、Cu、Mn营养中,P、Zn的不同配比会不同程度地改变Zn与Fe、Cu、Mn的协同或拮抗效应.