花椒种籽油的含蜡量测定与脱蜡

花椒种籽油的含蜡量测定与脱蜡是长期困扰花椒种籽油处理的一项关键技术,本研究通过分析混合压榨制备的花椒种籽油,花椒籽种壳油及种仁油的含蜡量,研究了5种脱蜡方法脱除花椒籽油中蜡质的脱蜡效果,确定了脱除花椒籽油中蜡质的有效方法,研究结果表明,花椒籽油的含蜡量在15－20％,左右,而这些蜡质基本上都含在种壳油内一即种壳上,种仁油基本不含蜡质,脱除花椒籽油中蜡质的合理方法应是：（1）含蜡量相对较低的精制粗油可选用表面活性剂法脱蜡;（2）当含蜡量相对较高时,为降低脱蜡过程中油的耗损率可选用分步脱蜡法脱蜡;（3）需进行碱炼的油,可在碱炼过程中将蜡质与游离脂肪酸一半除去。     

花生种皮蜡质和角质层与黄曲霉侵染和产毒的关系

黄曲霉侵染花生的研究表明,种皮破损的黄曲霉毒素含量显著高于种皮完整的,种皮对黄曲霉侵染和产毒起着重要屏障作用。采用氯仿去除种皮蜡质,用KOH或角质酶去除种皮角质层后,种子黄曲霉感染率和黄曲霉毒素含量显著提高。种皮蜡质和角质层同时去除的与种皮破损的黄曲霉感染率和毒素含量差异不显著,表明种皮的抗性成份主要是蜡质和角质层。种皮蜡质含量测定和种皮表面扫描电镜观察表明,蜡质的含量和角质层的厚度与品种的抗性有关。抗性品种种皮蜡质含量显著高于感病品种。种皮蜡质提取物在体外抑菌效果不显著。说明蜡质的抗性作用主要是物理性阻止黄曲霉菌的穿透。     

空气湿度与土壤水分胁迫对紫花苜蓿叶表皮蜡质特性的影响

选用2个抗旱性不同的紫花苜蓿品种,敖汉(强抗旱)和三得利(弱抗旱),设置空气湿度(45%-55%和75%-85%)和土壤水分胁迫(75%和35%田间持水量)处理,分析紫花苜蓿叶表皮蜡质含量、组分及晶体结构、气体交换参数、水势及脯氨酸含量的变化规律。结果表明,单独土壤水分胁迫时,紫花苜蓿叶表皮蜡质晶体结构及蜡质总量无显著变化;敖汉蜡质组分中烷类、酯类含量增加,醇类含量下降;三得利醇类含量下降,烷类、酯类含量变化不显著。低空气湿度胁迫时,两品种蜡质总量无显著变化,烷类和酯类含量显著增加,醇类含量显著下降,叶表皮片状蜡质晶体结构熔融呈弥漫性,扩大了对叶表面积的覆盖,其蒸腾速率显著低于正常湿度。复合胁迫处理时,叶表皮片状蜡质晶体结构继续呈弥漫性,烷类、酯类、未知蜡质组分含量均高于单独胁迫处理,醇类含量最低,而蜡质总量除三得利显著高于对照外,其余均无显著差异。紫花苜蓿叶表皮蜡质各组分含量(除醇类)及蜡质总量与光合速率呈显著负相关,与蒸腾速率无显著相关关系。蜡质总量与叶水势呈显著正相关。总体上,敖汉蜡质总量显著高于三得利,蜡质组分中烷类物质的增加有助于提高植株的抗旱性。在复合胁迫下,强抗旱品种主要通过气孔因素控制水分散失,而弱抗旱品种通过气孔和非气孔因素共同控制植物水分散失。     

影响加拿大一枝黄花种子非随机脱落的因素

为揭示加拿大一枝黄花(Solidago canadensis)种群扩散机制, 明确种子的脱落及风传扩散在其种群蔓延中的作用, 在人工环境下测定了不同湍流强度、风速和湿度处理下种子脱落的差异, 并对脱落种子与未脱落种子进行形态学特征对比。结果表明: 加拿大一枝黄花的种子脱落受湍流、风速和湿度等因素的共同影响。水平气流下种子的脱落阈值为5.1 m·s^-1, 并随着风速增加, 种子的脱落率增加。与模拟水平气流相比, 模拟垂直气流下种子的脱落阈值显著偏小。相对于层流状态, 湍流的存在显著提高了种子的脱落率, 平均增幅超过300%; 但单纯提高湍流强度对种子脱落率的影响不显著。增加湿度则显著降低种子的脱落率。种子形态学特征对比结果表明, 脱落种子的冠毛数量和冠毛夹角显著高于未脱落种子。该研究结果为研究加拿大一枝黄花种子脱落规律和风传扩散机制提供了科学依据, 也为其他入侵性杂草种子的扩散机制及入侵过程提供了 借鉴。     

Factors influencing the nonrandom abscission of Solidago canadensis seeds

 为揭示加拿大一枝黄花(Solidago canadensis)种群扩散机制, 明确种子的脱落及风传扩散在其种群蔓延中的作用, 在人工环境下测定了不同湍流强度、风速和湿度处理下种子脱落的差异, 并对脱落种子与未脱落种子进行形态学特征对比。结果表明: 加拿大一枝黄花的种子脱落受湍流、风速和湿度等因素的共同影响。水平气流下种子的脱落阈值为5.1 m·s^–1, 并随着风速增加, 种子的脱落率增加。与模拟水平气流相比, 模拟垂直气流下种子的脱落阈值显著偏小。相对于层流状态, 湍流的存在显著提高了种子的脱落率, 平均增幅超过300%; 但单纯提高湍流强度对种子脱落率的影响不显著。增加湿度则显著降低种子的脱落率。种子形态学特征对比结果表明, 脱落种子的冠毛数量和冠毛夹角显著高于未脱落种子。该研究结果为研究加拿大一枝黄花种子脱落规律和风传扩散机制提供了科学依据, 也为其他入侵性杂草种子的扩散机制及入侵过程提供了借鉴。     

矮沙冬青种子特性和萌发影响因素的研究

 对矮沙冬青(Ammopiptanthus nanus)种子的特性和萌发影响因素进行了初步研究,结果表明：种子不易传播;虫蛀率高,室温贮藏60 d的种子虫害率为38%;易形成硬实,含水量为7.68%的种子在30 ℃温水中浸泡90 h,只有33.33%能吸水膨胀。种子萌发时不需光,在15～30 ℃和室温（18～32 ℃）条件下,经9 d的萌发,发芽率均可达80%以上,30℃时萌发最快;在1～2 cm深的沙壤中,种子出苗率可达75%以上,超过3 cm显著降低,超过6 cm则低于20%;种子在沙壤中萌发时,沙壤的适宜湿度为19.35%～28.75%,高于32.43%或低于3.85%,很少有种子萌发;含水量分别为19.36%、10.64% 和7.68%的种子发芽率无显著差异,在-10 ℃和5 ℃下贮藏7个月,发芽率也无显著降低,但在室温和35 ℃下贮藏7个月则显著下降,发芽率下降的速度与种子本身的含水量和贮藏温度正相关;在湿度分别为7.41%、13.79%和28.57%的沙壤中播种育苗,幼苗死亡率高达77.49%、81.25%和89.49%,即使用三唑酮拌种,死亡率亦高达50.27%、69.53%和76.03%,幼苗死亡率与沙壤湿度正相关。     

青钱柳天然群体种子性状表型多样性

以青钱柳分布区内的9个天然群体种子为试材,对种子千粒重、体积、直径、厚度和径厚比5个表型性状进行了系统的比较分析,采用方差分析、相关分析及聚类分析等方法对群体间和群体内的表型多样性进行探讨.结果表明: 青钱柳种子千粒重、体积、直径及厚度在群体间和群体内均达到显著或极显著差异,而种子径厚比仅在群体内存在极显著差异,说明青钱柳种子性状在2个层次上都具有丰富的多样性.各性状的平均表型分化系数（V）为20.54%,即群体间的变异远低于群体内的变异（79.46%）.种子性状与地理因子相关程度存在差别,且受年均气温的影响最大.利用群体间欧氏距离进行系统聚类分析,青钱柳群体可以划分为三类.     

苦瓜叶片结构与白粉病抗性的关系

以不同抗白粉病的苦瓜品系幼苗为材料,对它们的叶片及上下表皮厚度、栅栏组织及海绵组织厚度、叶片结构紧密度及疏松度、蜡质含量、比叶重、气孔及茸毛密度等叶片结构进行观察比较,探讨苦瓜白粉病抗性与其主要叶片结构指标的关系。结果显示:（1）抗病苦瓜品系叶片的蜡质含量显著高于感病品系,与病情指数呈显著负相关关系,蜡质层是其抵抗和延迟病原菌侵入的一个有力结构屏障。（2）感病品系叶片的气孔和叶背面茸毛数量显著多于抗病品系,且叶背面的气孔及茸毛密度与病情指数呈显著正相关关系,即气孔和茸毛越少越抗病。（3）抗病苦瓜品系的叶片栅栏组织以及海绵组织排列整齐、紧密,而高感品系的叶片组织出现大量孔隙,较难观察到完整细胞。（4）抗病品系叶片厚度、下表皮厚度、栅栏组织厚度、叶片结构紧密度明显高于感病品系,而感病品系的海绵组织厚度、叶片结构疏松度明显高于抗病品系;且苦瓜比叶重与其白粉病抗性关系不大。研究认为,苦瓜叶片蜡质含量、叶背面气孔及茸毛密度可以作为苦瓜白粉病抗性鉴定的参考指标。     

UV-B辐射增强对拟南芥表皮蜡质的影响

以野生型拟南芥、蜡质不同程度缺失突变体CER1、CER3、CER4、CER6、CER10、CER20及KCS1为试验材料,通过施加50μW/cm2、长达10 d的UV-B辐射,研究了拟南芥表皮蜡质晶体结构、组分及蜡质基因对UV-B辐射的响应机制。结果表明:UVB辐射增强改变了拟南芥表皮蜡质晶体结构,表皮蜡质松针状(CER1)、柱状、杆状(CER3、CER10与KCS1)晶体结构显著减少,球状蜡质晶体类型出现在CER6表面,无规则片状、膜状结构覆盖在KCS1与CER10茎表面。野生型拟南芥蜡质晶体结构类型无明显变化,但在部分区域积累了大量水平杆状、管状结构,增加了蜡质层厚度。UV-B辐射增强也改变了拟南芥表皮蜡质组分的分泌量。野生型在UV-B处理后一级醇、酸、醛含量显著上升,烷、次级醇及酮含量显著下降,蜡质总量增加不显著。一级醇含量的增加及酮和次级醇含量的减少在拟南芥各材料响应UV-B辐射中具有普遍性。UV-B辐射增强诱导了野生型CER3、CER4、KCS1基因表达的上调,其中CER4大量表达,促进了蜡质组分中一级醇、酸和醛含量的积累;CER1在UV-B处理后表达量下调,可能导致烷合成下游分支途径相关产物(烷类、次级醇及酮类)的减少。WIN1表达量的下调对蜡质总量没有显著影响。UV-B辐射增强使蜡质前体从烷合成分支途径更多地转向一级醇分支途径。     

国外引进优良黄麻种质生物学鉴定与利用

通过对从国外引进的12份黄麻优异种质进行3年的生物学鉴定,结果表明：引进种质大多为晚熟、绿茎、有腋芽,披针或卵圆形叶,生长较整齐。其中O—4叶片蜡质含量明显高于我国品种;O-5叶柄紧贴主茎。短光照处理未发现对光不敏感品种,但分期播种未见早花现象。所有品种在我国黄麻主产区均能正常生长与收获纤维,但晚熟品种只能在华南麻区才可收获成熟种子。     

Raman spectroscopic evaluation of efficacy of current paraffin wax section dewaxing agents.

During a spectroscopic study to identify biochemical changes in cervical tissue with the onset of carcinogenesis, residual paraffin wax contributions were observed on almost all dewaxed formalin-fixed paraffin-processed (FFPP) tissue sections examined. Subsequently, the present study was formulated to evaluate the efficacy of current dewaxing agents using Raman spectroscopy. Three cervical FFPP sections were subjected to each of the protocols. Sections were dewaxed using four common dewaxing protocols, namely, xylene, Histoclear, heat-mediated antigen retrieval (HMAR) using xylene and citrate buffer, and Trilogy (combined deparaffinization and unmasking of antigens). The potential for hexane as a dewaxing agent was also evaluated. Sections were dewaxed in multiple dewaxing cycles using xylene, Histoclear, and hexane. Residual paraffin wax contributions remained at 1062 cm(-1), 1296 cm(-1), and 1441 cm(-1). HMAR using xylene and citrate buffer, and HMAR using Trilogy, showed a similar efficacy, resulting in incomplete removal of wax. Hexane was shown to be the most effective dewaxing agent, resulting in almost complete removal of wax. Immunohistochemistry was carried out on dewaxed slides, and those dewaxed with hexane displayed a stronger positivity (approximately 28%). Implications for histopathology and immunohistochemistry are considered, as well as problems that residual wax poses for spectroscopic evaluation of dewaxed FFPP sections with a view to disease diagnosis.     

Improved diethylene glycol distearate embedding wax

Diethylene glycol distearate wax and cellulose caprate resin, 4:1 respectively by weight, were melted together at 75 C for five hours with occasional stirring. The resin tempered the extreme brittleness of the wax without softening it, and raised the melting point only one degree to 50 C. Fixed plant tissues were dehydrated in ethanol, cleared in xylene, and infiltrated with wax. Modified diethylene glycol distearate was easier to trim and shape, and formed flat sections more consistently than the pure wax. Sections were cut singly on Ralph knives with attached water pools on an ultramicrotome. Sectionability was excellent at 2-3 micrometers, variable at 1.0 micrometer, but impossible at 0.5 micrometer. Sections were transferred onto water drops on slides, dried, dewaxed, stained, and coverglasses applied as in the paraffin method. Histological feature of plant tissues were much sharper in modified diethylene glycol distearate sections than in paraffin sections, and were similar to plastic sections.     

Impact of feeding,molting and relative humidity on cuticular wax deposition and water loss in the lone star tick,Amblyomma americanum

To determine whether there is a correlation between the amount of lipids on the surface of ticks and their permeability to water, we quantified cuticular surface wax and measured water-loss rates in the ixodid tick Amblyomma americanum from nonfed nymph to egg-laying female. Ticks deposited no extra cuticular lipids during feeding, permitting maximum transpiratory water loss that presumably helps to concentrate the bloodmeal; and ticks deposited additional cuticular wax after apolysis that reduced integumental water loss, which likely prepares ticks for off-host existence. A remarkable three-fold boost in surface wax deposition and extreme water retention were noted after host drop-off following feeding. This wax is likely host-derived. Fed nymphs could discriminate between low and high relative humidity, enabling pharate adults to conserve lipid that would otherwise be lost with the exuvia and feces. This conservation strategy likely adds to the lipid pool needed by the tick to survive in a dry environment and complements the tick's behavioral abilities for seeking out optimum conditions for water conservation and host location.     

Extraction and characterization of wax from sugarcane bagasse and the enzymatic hydrolysis of dewaxed sugarcane bagasse

Extraction of high-value products from agricultural wastes is an important component for sustainable bioeconomy development. In this study, wax extraction from sugarcane bagasse was performed and the beneficial effect of dewaxing pretreatment on the enzymatic hydrolysis was investigated. About 1.2% (w/w) of crude sugarcane wax was obtained from the sugarcane bagasse using the mixture of petroleum ether and ethanol (mass ratio of 1:1) as the extraction agent. Results of Fourier-transform infrared characterization and gas chromatography–mass spectrometry qualitative analysis showed that the crude sugarcane wax consisted of fatty fractions (fatty acids, fatty aldehydes, hydrocarbons, and esters) and small amount of lignin derivatives. In addition, the effect of dewaxing pretreatment on the enzymatic hydrolysis of sugarcane bagasse was also investigated. The digestibilities of cellulose and xylan in dewaxed sugarcane bagasse were 18.7 and 10.3%, respectively, compared with those of 13.1 and 8.9% obtained from native sugarcane bagasse. The dewaxed sugarcane bagasse became more accessible to enzyme due to the disruption of the outermost layer of the waxy materials.     

The influence of hygroscopic movement on seed dispersal in Daucus carota (Apiaceae)

Summary The influence of hygroscopic movement on seed dispersal in Daucus carota was examined. When relative humidity increases, umbels containing mature fruits close; when relative humidity drops, umbels open. Tests of the effectiveness of smalland large-angled umbels on dispersing seeds under various conditions demonstrate that umbels responding greatly to relative humidity (i.e. opening wide) lose seeds more quickly than do umbels responding little, and do not disperse them as far. As relative humidity increases, number of dispersing seeds drops to near zero. Response to changes in relative humidity within an umbel progressively increases from late August when dispersal begins. Umbels that slowly increase their response retain some seeds that may disperse over snow in winter. Individual variation in response to relative humidity is high among plants beginning dispersal at the same time. This variability is probably maintained by the variable consequences of dispersing seeds at different times.     

Isolation of Avian Trypanosomes by Selective Centrifugation and Subsequent Processing for Electron Microscopy

Paraffin sections are usually rehydrated before staining. It is possible to apply aqueous dye solutions without first removing the wax. Staining then occurs more slowly, and only if the embedding medium has not melted or become unduly soft after catting. To avoid this problem, sections are flattened on water no hotter than 45 C and dried overnight at 40 C. Minor technical modifications to the staining procedures are needed. Mercury deposits are removed by iodine, and a 3% solution of sodium thiosnlfate in 60% ethanol is used to remove the iodine from paraffin sections. At room temperature, progressive staining takes 10–20 tunes longer for sections in paraffin than for hydrated sections; at 45 C, this can be shortened to about three times the regular staining time. After staining, the slides are rinsed in water, air dried, dewaxed with xylene, and coverslipped in the usual way. Nuclear staining in the presence of wax was achieved with toluidine blue, O, alum-hematoxylin and Weigert's iron-hematoxylin. Eosin and van Gieson's picric acid-acid fuchsine were effective anionic counterstains. A one-step trichrome mixture containing 3 anionic dyes and phosphomolybdic acid was unsuitable for sections in wax because it Imparted colors that were nninformative and quite different from those obtained with hydrated sections. Advantages of staining in the presence of wax include economy of solvents, reduced risk of overstaining and strong adhesion of sections to slides.     

Staining Paraffin Sections Without Prior Removal of the Wax

Paraffin sections are usually rehydrated before staining. It is possible to apply aqueous dye solutions without first removing the wax. Staining then occurs more slowly, and only if the embedding medium has not melted or become unduly soft after catting. To avoid this problem, sections are flattened on water no hotter than 45 C and dried overnight at 40 C. Minor technical modifications to the staining procedures are needed. Mercury deposits are removed by iodine, and a 3% solution of sodium thiosnlfate in 60% ethanol is used to remove the iodine from paraffin sections. At room temperature, progressive staining takes 10-20 tunes longer for sections in paraffin than for hydrated sections; at 45 C, this can be shortened to about three times the regular staining time. After staining, the slides are rinsed in water, air dried, dewaxed with xylene, and coverslipped in the usual way. Nuclear staining in the presence of wax was achieved with toluidine blue, O, alum-hematoxylin and Weigert's iron-hematoxylin. Eosin and van Gieson's picric acid-acid fuchsine were effective anionic counterstains. A one-step trichrome mixture containing 3 anionic dyes and phosphomolybdic acid was unsuitable for sections in wax because it Imparted colors that were nninformative and quite different from those obtained with hydrated sections. Advantages of staining in the presence of wax include economy of solvents, reduced risk of overstaining and strong adhesion of sections to slides.     

DEVELOPMENT OF THE CUTICULAR LAYERS IN ANGIOSPERM LEAVES

Schieferstein , R. H., and W. E. Loomis . (Iowa State U., Ames.) Development of the cuticular layer in angiosperm leaves. Amer. Jour. Bot. 46(9): 625–635. Illus. 1959.—The cuticularized layers of leaves and other plant surfaces consist of a primary cuticle, formed by the oxidation of oils on exposed cell walls, plus various surface and subsurface wax deposits. The primary cuticle appears to form rapidly on the walls of any living cell which is exposed to air. Surface wax is present on the mature leaves of about half of the 50 or 60 species studied. In general, wax is extruded at random through the newly formed cuticle of young leaves and accumulated in various reticulate to semicrystalline patterns. No wax pores through the cuticle or primary wall can be observed in electron-micrographs of dewaxed mature leaves. Wax accumulations on older leaves are generally subcuticular and may involve the entire epidermal wall. These deposits appear to be of considerably greater ecological significance than those on the surface. Isolated cuticular membranes from Hedera helix increased slightly in permeability to water with age of the leaf, but permeability to 2,4-D decreased 50 times. Evidence based on the patterns of cellulose in primary walls, of surface wax on growing leaves, of the appearance of the cuticle at the margins of growing epidermal cells, of the forms of the cuticle plates digested from growing and older leaves, and of the marginal location of new wax deposits on growing maize leaves is presented to support the thesis that the enlargement of the outer surface of the epidermal cells of leaves occurs at the margins of the surface. Earlier formed cuticle and wax are thus undisturbed during growth. These observations, coupled with evidence for apical growth in fibers, root hairs, etc. suggest that the primary walls of angiosperm cells are formed in specific, localized growth regions, rather than by plastic extension and apposition.     

Leaf surface wax and plant morphology of peas influence insect density

Insect predators and parasitoids adhere better, forage more effectively, and take more aphid prey on pea plants (Pisum sativum L.) (Leguminosae) with mutations that reduce the crystalline wax bloom on the plant surface. To assess the agronomic potential of this trait for pest management, abundance of pea aphids (Acyrthosiphon pisum L.) (Homoptera: Aphididae) and coccinellid predators, and percent parasitism of the aphids were evaluated on pea lines differing in wax bloom and plant architecture over two field seasons. Three pairs of pea lines were evaluated, each pair with a different architecture and differing within the pair in the amount of surface wax bloom (reduced or normal). The trials included plots treated with a narrow spectrum insecticide (pymetrozine) to reduce aphid populations and untreated controls. Reduced wax peas had significantly fewer aphids per plant in 2002 but not in 2003. Total natural enemy abundance was greater on reduced wax than on normal wax pea lines in both years of the study. Pymetrozine reduced aphid densities significantly in both years. Among the four pea lines evaluated for yield, seed yield per plant was affected by plant morphology and insecticide treatment. Yield was greatest on semileafless plants and on pymetrozine sprayed plots in both years. Yield of the reduced wax line in the semileafless background was similar to or exceeded yield in its normal wax sister line, suggesting that this morphological type was best for an agronomically viable reduced wax phenotype. Pea weevil (Bruchus pisorum L.) (Coleoptera: Bruchidae) damage to seed was overall more frequent on seeds from reduced wax varieties than from normal wax varieties. The results illustrate the trade‐offs associated with a reduced wax trait in peas but also show that certain combinations of reduced wax and gross morphology lead to reduced pea aphid populations and yields similar to those of normal wax peas.