茶树鲜叶抗坏血酸过氧化物酶活性的变化规律及测定方法

探讨茶树鲜叶抗坏血酸过氧化物酶(APX)活性的测定条件,分析不同茶树品种以及茶树鲜叶不同叶位APX活性的变化.结果表明:聚乙烯聚吡咯烷酮(PVPP)加入量约为鲜叶重的1.5倍,酶提取液pH为7.8.反应液pH为7.O,抗坏血酸(AsA)浓度为0.50 mmol/L时茶树鲜叶APX活性最高;茶树鲜叶APX活性随冷藏时间的延长呈下降趋势;福建7个主要茶树品种以福鼎大白茶的APX活性最高,铁观音的APX活性最低;茶树鲜叶不同叶位APX活性变化趋势为:芽>第一叶>第二叶>第三叶>老叶>嫩茎.     

多效唑影响朱顶红植株生长的转录组分析

朱顶红具有较高观赏价值,但其高花茎和叶太长成为其发展盆栽的限制因素.本研究应用不同浓度的多效唑(paclobutrazol,PBZ)对朱顶红进行处理,观测其表型性状的特征,并应用RNA-seq技术进行转录本分析.结果 表明,PBZ对朱顶红的株高及叶片长度具有抑制作用,随着PBZ浓度的增加,其株高越矮,叶长逐渐变短,各处...     

Impact of the chilling conditions on the kinetics of staling of bread

Breads were chilled at room temperature or using a vacuum chilling process. The staling rate was studied after partial baking and after the final baking. Vacuum chilled breads (VCBs) exhibited a higher moisture loss than conventionally chilled bread (CCB). A higher enthalpy of melting of amylopectin crystals was observed for VCB in comparison to CCB.VCB had a negative effect on the texture of the bread. The hardness of the crumb of VCB was increased by 20% at the end of staling and the kinetics of staling was 10% faster for VCB in comparison to CCB. After 12 days of storage at 4 °C, a second and final baking was applied to the bread. The staling rate of VCB was almost two times that of CCB. The staling rate of CCB was unchanged in comparison to the staling rate after partial baking. Data on the enthalpy of melting of amylopectin showed that the same amount of amylopectin was formed at the end of staling for CCB after part baked process and after full baking process. Beside, the VCB showed a higher amount of recrystallized amylopectin (10%) at the end of the staling which followed the partial baking.     

再论超级麦育种

优质、高产、多抗是我国小麦育种的主要目标。为了高效利用资源和保护环境 ,应从提高肥水利用效率入手 ,培育超级麦品种 ,来实现少种多收、提高经济效益的目标。超级麦是肥水利用效率高、品质好、高产、抗逆性好的新一类生产品种的总称。培育超级麦品种需要革新现有育种技术 ,改良品种的代谢特性 ,提高对土壤、氮、磷、水分等资源的使用效率     

Weibull distribution analysis of the tensile strength of the kenaf bast fiber

This paper presents the influence of the gage length on the kenaf fiber Young’s modulus and the tensile strength characterization. Four different gage lengths of 10 mm, 15 mm, 20 mm and 25.4 mm are selected in this study and the tensile testing is performed at a quasi-static loading rate of 1 mm/min. The cross-sectional area of the fiber after failure is considered for the stress calculations. Weibull probability distribution is used to characterize the tensile strength of the kenaf fiber. The Weibull parameters are obtained for the two parameter, three parameter and Weibull of Weibull models and the average tensile strength of the fibers are evaluated. The predicted average tensile strength from all the three approaches are in good agreement with the experimental results for the obtained parameters.     

玉米丝黑穗病菌致病力分化研究

采用土壤接种方法,对采自黑龙江省不同玉米生产区的3个菌株进行了致病力分化测定。试验结果表明,来自不同地区的菌株对同一玉米自交系(品种)的致病力无明显差异。哈尔滨、佳木斯和肇东的3个菌株对Mo17和维27的发病率为0～5%,哈尔滨的菌株对龙抗11的发病率为9.4%。相对比较而言,佳木斯和肇东地区的菌株致病力稍低。     

大孔吸附树脂法纯化黄花草木樨总皂苷工艺的研究

目的优化大孔吸附树脂法纯化黄花草木樨叶中总皂苷的工艺。方法：以黄花草木樨中总皂苷的含量为指标,考察了5种大孔吸附树脂对黄花草木樨中总皂苷的吸附及解吸效果,筛选出最适皂苷纯化的树脂,并对纯化工艺进行了优化。结果：AB-8大孔吸附树脂适合纯化黄花草木樨中的总皂苷,最佳洗脱条件为：上样浓度为1．0mg／ml,上柱吸附流速为2．0ml·min^-1,以70％乙醇洗脱,洗脱流速2．0ml·min^-1,洗脱体积为5BV。结论所选工艺方法简便,稳定,纯化效果好。     

Effect of drying condition on the electrostatic characteristics of the laundry

This paper suggests the optimal conditions to prevent electrostatic charge in the laundry by the evaluation of the electrostatic characteristics during the drying process. Cotton, nylon, and polyester fabrics were used as test specimens, employing the standard washing cycle. The electrostatic characteristics of the laundry were measured after the automatic drying process. This paper investigates the optimal conditions for preventing electrostatic charges in laundry by evaluating the electrostatic characteristics that occur during the drying process. Cotton, nylon, and polyester fabrics were used as the test specimens, employing a standard washing cycle. The electrostatic characteristics of the laundry were measured immediately after the automatic drying process. The results, showed that the moisture content decreased and the electrostatic charge increased with drying time. The specimen fabrics had already dried up before completion of the standard drying cycle. Consequently, the excessive drying generated an electrostatic charge due to removal of the traces of remaining moisture and the resulting excessive friction. For cotton fabrics, the electrostatic charge was under 1000 V even for the maximum drying time due to the intrinsic high moisture regain of cotton. On the other hand, the electrostatic charge produced for nylon fabrics increased rapidly with the drying time, and amounted up to approximately 8000V after 120 minutes. The results also indicated that the electrostatic charge could be decreased by drying fabrics of only one kind. When mixed kinds of fabrics were dried, the electrostatic charge increased remarkably. Therefore, it is suggested that laundry be classified and washed according to the kinds of fiber, and not be dried excessively to reduce electrostatic charge. In addition, the proper use of a softener is effective in reducing the electrostatic charge.     

Mapping the influence of electrospinning parameters on the morphology transition of short and continuous nanofibers

A theoretical model for the morphology transition of short and continuous nanofibers by electrospinning has been proposed. The influences of polymer concentration, applied voltage, and flow rate on the fabrication of short and continuous nanofibers were mapped for use as a reference in the design and construction of the theoretical model. The morphology transition of short and continuous nanofibers occurred mainly due to changes in the flow rate and voltage. According to the concentration of the polymer in the solution, the map of the short nanofiber region was narrowed as the polymer concentration increased. The theoretical model derived from the conservation of kinetic energy and potential energy experienced by the polymer solution resulted in an equation that could be used to calculate the voltage and flow rates under certain boundary conditions when cutting nanofibers. The boundary conditions for voltage were 4.7-4.9 kV, and the boundary conditions for flow rate were 0.1-1.1 µl/min.     

稻米糊化温度特性形成规律研究

利用差示扫描量热仪(DSC)对花后5 d起灌浆期间稻米糊化温度特性进行了研究。结果表明,糊化温度特性是随着谷粒的成熟而逐步形成的,表现出由高到低并逐渐趋于稳定的趋势。低糊化温度水稻品种黄玉B和高糊化温度品种Ⅱ32B的起始糊化温度(To)分别在花后第7 天和第9 天达到稳定,此后不再显著下降。两个品种花后5 d的稻米峰值温度(Tp)和终结温度(Tc)均极显著高于此后的稻米样本;花后7~25 d,黄玉B的Tp和Tc都出现了下降 上升 下降 上升的过程,但花后7 d和25 d的值没有显著差异;Ⅱ32B的Tc的变化与黄玉B相似,但其Tp只出现了一个下降 上升过程,且开花后7 d的Tp显著高于开花后25 d。这些结果表明,高、低糊化温度品种糊化温度特征的形成可能存在差异,在生产实践中,应该针对不同品种类型加以调控。     

红麻茎发育的解剖研究初报

本文是对红麻茎发育进行解剖研究的结果。研究表明:红麻茎韧皮纤维层、木质部的发育均以旺长期最快;束纤维横切面积是后分化大于先分化的纤维束,而单纤维横切面积则是先分化大于后分化的纤维;红麻茎木质部发育的速度往往数倍于韧皮部;不同肥料对麻茎生长的影响,N肥以生长前期影响最大,而K肥对麻茎发育的影响以旺长期效果最为明显,作为选纸原料的红麻更应重施K肥。     

汉中市生态观光茶园发展现状与对策

在分析汉中市发展生态观光茶园现状和优势的基础上,提出了相应发展对策,旨在为汉中茶旅游开发提供参考。     

HPLC法测定抗炎片中黄芩苷的经时变化

目的：通过改变煎煮时间,研究黄芩苷的提取工艺,从而确定最佳条件。方法：选用单因素水平法,考察提取时间对黄芩苷收率的影响。利用HPLC法测定黄芩提取物中黄芩苷的含量。结果：黄芩在提取2次,提取时间均为60min的条件下,黄芩的出膏率和黄芩苷的含量最高。结论：水提方法合理,收率高,成本低,适用于黄芩苷的提取。     

海南侨植农场砖厂附近橡胶树受害原因分析

为探明侨植农场砖厂附近橡胶树的受害原因，对受害橡胶树的表现症状、土壤、叶片养分及氟化物含量进行调查。结果表明：受害胶树的症状与植物生理学上氟化物伤害症状相符，排除了病虫害等致害因素；受害胶树周围土壤的主要养分指标处于正常水平，土壤养分不存在亏缺状态；受害胶树叶片的主要养分指标同样处于正常水平，叶片不存在缺素症状；受害胶树周围土壤和叶片中的氟化物含量显著高于正常值水平。鉴于该砖厂为受害胶树附近唯一的氟化物污染源，因此认为该砖厂排放的氟化物是导致胶树受害的主要原因。     

Characterisation of the substrate specificity of the nitrile hydrolyzing system of the acidotolerant black yeast Exophiala oligosperma R1

The ‘black yeast’ Exophiala oligosperma R1 can utilise various organic nitriles under acidic conditions as nitrogen sources. The induction of a phenylacetonitrile converting activity was optimised by growing the strain in the presence of different nitriles and /or complex or inorganic nitrogen sources. The highest nitrile hydrolysing activity was observed with cells grown with 2-cyanopyridine and NaNO₃. The cells metabolised the inducer and grew with 2-cyanopyridine as sole source of nitrogen. Cell extracts converted various (substituted) benzonitriles and phenylacetonitriles. They usually converted the isomers carrying a substituent in the meta-position with higher relative activities than the corresponding para- or ortho-substituted isomers. Aliphatic substrates such as acrylonitrile and 2-hydroxy-3-butenenitrile were also hydrolysed. The highest specific activity was detected with 4-cyanopyridine. Most nitriles were almost exclusively converted to the corresponding acids and no or only low amounts of the corresponding amides were formed. The cells hydrolysed amides only with extremely low activities. It was therefore concluded that the cells harboured a nitrilase activity. The specific activities of whole cells and cell extracts were compared for different nitriles and evidence obtained for limitation in the substrate-uptake by whole cells. The conversion of 2-hydroxy-3-butenenitrile to 2-hydroxy-3-butenoic acid at pH 4 demonstrated the unique ability of cells of E. oligosperma R1 to hydrolyse aliphatic α-hydroxynitriles under acidic conditions. The organism could grow with phenylacetonitrile as sole source of carbon, energy and nitrogen. The degradation of phenylacetonitrile presumably proceeds via phenylacetic acid, 2-hydroxyphenylacetic acid, 2,5-dihydroxyphenylacetic acid (homogentisate), maleylacetoacetate and fumarylacetoacetate.     

橡胶树种子电导率特性及其与种子活力的关系

用完整的橡胶树种仁在室温下浸泡于无离子水中测定种子渗漏质电导率。研究结果表明,橡胶树种子渗漏质电导率与浸泡时间之间呈直线相关,因品种、种子质量、贮存时间和季节而异,但这种差异是相对稳定的。不同质量的橡胶树种子的电导率之间的显著差异可以在种子浸泡7h内观测到。橡胶树种子电导率与发芽率及籽苗生势之间均呈显著负相关关系。因此,橡胶树种子电导率有可能作为快速测定橡胶树种子活力的一个重要指标。另外,橡胶树种子在敞开贮存期间,种子电导率出现波动性变化现象,这种变化也因品种和种子质量等而异。      

水稻倒伏发生规律及防御技术的研究进展

倒伏是水稻生产中的一个严重问题,水稻茎秆倒伏严重影响水稻产量和稻谷品质,倒伏发生越早,损失越大。本文从水稻倒伏发生规律和防御技术等方面,综述了水稻倒伏发生规律和防御技术研究进展,提出了有待拓宽和深化研究的内容。     

南繁条件下转基因棉花对根际土壤微生物及棉田虫害影响的初步研究

转基因作物安全评价是当前生物安全研究的重要内容。本实验以海南三亚南繁基地为实验平台,通过比较转BT/CPTI双价基因抗虫棉花SGK321和非转基因棉花石远321根际土壤微生物动态变化,初步研究了转基因棉花SGK321对农田生态环境的影响。通过常规培养计数、分子鉴定等手段监测土壤微生物多样性变化,经过近两年的跟踪研究,发现两次生长周期内,转基因棉花SGK321和非转基因棉花石远321根际土壤微生物(包括细菌、真菌、放线菌)的动态变化趋势大致相同,群落数量和种属组成都没有明显差异。此外,南繁大田种植环境条件下,除棉铃虫数量差异明显外,其余各种棉田虫害数量差异不明显。据此,我们初步推断南繁条件下转基因棉花SGK321的种植对土壤微生物及棉田虫害影响不显著。本研究可为在我国南繁基地开展转基因作物安全评价提供参考。     

Confirmation of the Productivity of the Stored Seeds of Wheat and Two-Rowed Barley

Summary

To confirm the excellence in productivity of the stored seeds of wheat and two-rowed barley, we examined the growth characters and productivity of the plants developed from the seeds stored at 5°C and 40% relative humidity for various periods but showed a 80% or higher germination percentage, in comparison with those of newly harvested seeds (new seeds). The cultivars of stored seeds were identified by the random amplified polymorphic DNA (RAPD) method. There were no differences in the morphological characters of the seedlings 3 months after emergence between the new seeds and the old seeds (stored for 2 years and 5 months) or the very old seeds (stored for 10 years and 5 months or 16 years and 5 months). On the other hand, there was a positive correlation between the top dry weight at 3 months after emergence and 1,000-grain weight of the seed. In the plants from the old seeds, no significant differences from those from new seeds were observed either in the mean heading date, maturing date, culm lengths, ear length, yield components, grain yield or inspection-grade. On the other hand, in the plants from the very old seeds, the mean heading date, maturing date, culm lengths, yield components and grain yield were significantly different from those in the new seeds in some cultivars. The results of RAPD analysis showed that the band pattern of the very old seeds was the same as that of the new seed in each cultivar. We concluded that the seeds of wheat and two-rowed barley stored for 2 years and 5 months with a germination percentage of higher than 80% are practically useful, showing normal growth characters and productivity. However, it should be noted that some cultivars had inferior grain yield after the seed storage for over 10 years.     

大豆异黄酮的提取优化与测定

试验优化了大豆异黄酮的提取方法,建立了一套适用于实验室提取、测定异黄酮含量的高效液相色谱法(HPLC)标准体系。优化后建立的提取条件为:脱脂大豆样品粉末,加入体积浓度为80%的色谱级甲醇10 mL,室温下放置2 h,置于超声功率200 W条件下80℃水浴12 h,12 000 r·min~(-1)离心15 min,取上清液经0.45μm微孔滤膜过滤,待测液4℃保存。优化后的HPLC法:流动相选择甲醇-水(体积比30∶70),柱温设置40℃,波长为254 nm,流速为1 mL·min~(-1),进样体积10μL,进样时间26 min,采用峰面积法计算。结果表明:优化的HPLC法提取大豆异黄酮的效率高、精度高,可为实验室内高效提取大豆异黄酮提供技术参考。