基于主成分分析法的白茶香气质量评价模型构建

香气质量是茶叶品质的主要因子,常用感官审评法评价,但此法带有主观性且很难定量。为探索客观评价白茶香气质量的方法,笔者采用顶空固相微萃取-气质联用法(HS-SPME-GC-MS)测定12个白茶样的香气成分,利用主成分分析法构建白茶的香气质量评价模型,并对其可行性进行了探讨。结果表明:12个白茶中W6的香气质量最好,模型检验结果与感官审评结果相同;同传统感官审评相比,模型评价不同茶叶的香气分数差别较大,更容易区分茶叶香气品质。本研究构建的评价模型具有客观性和可操作性,可替代感官审评法对白茶香气品质进行评价。     

白茶感官品质与化学成分的相关和通径分析

为了定量分析主要生化成分在白茶感官品质决定中所起作用的大小，以新选801、新选807、福鼎大毫和金牡丹4个茶树品种分别在3个不同萎凋条件下制得的12个白茶茶样为材料，测定氨基酸、茶多酚、水浸出物、还原性糖和咖啡碱含量及感官审评得分，用SPSS19.0数据分析软件对主要化学成分与白茶品质进行相关和通径分析。结果表明，白茶的感官审评得分与氨基酸含量（R=0.855）成极显著正相关，与还原性糖含量（R=0.680）成显著正相关，与水浸出物含量（R=-0.873）和酚氨比（R=-0.841）成极显著负相关；对感官品质直接正面影响较大的化学成分为还原性糖和氨基酸；而茶多酚和咖啡碱则对感官品质产生直接负面影响。     

南安市不同乌龙茶品种试制白茶的品质比较和发展对策研究

试验以五种高香乌龙茶茶树品种-金观音、铁观音、水仙、本山、毛蟹的鲜叶为原料按照相同的白茶加工工艺流程和技术参数制得成品茶,并对成品茶进行感官审评,以比较不同品种所制白茶的品质差异情况.结果表明:五个品种均适制白茶,但以金观音白茶品质最优,所制产品银绿较鲜活、滋味甘鲜、有明显花香味.     

浙江省主栽茶树品种工艺白茶的滋味成分研究

采摘浙农113、春雨1号、春雨2号、迎霜、鸠坑和安吉白茶6个浙江省主栽品种茶树鲜叶,按传统工艺加工白茶,跟踪测定加工过程中茶叶主要滋味成分的动态变化规律,以福鼎大毫茶品种为对照,对所得产品进行感官审评与理化分析。结果表明,萎凋过程中茶多酚与儿茶素含量降低,氨基酸含量升高。福鼎大毫茶的鲜度、苦度、涩度均为最强,安吉白茶甜度最强。浙农113、春雨1号、春雨2号感官审评综合品质最优,且喜好度最高。不同品种白茶间滋味成分含量差异显著,酯型儿茶素与白茶的苦度、涩度呈极显著正相关,与甜度呈显著负相关,鲜味氨基酸与鲜度呈显著正相关。综合感官审评与滋味品质成分,春雨1号与传统白茶风格最为接近,浙农113与春雨2号可以用于开发浙江白茶新产品。     

高γ-氨基丁酸白茶品种适制性研究

本试验以9个茶树品种为试验材料,采用真空厌氧加工技术加工高γ-氨基丁酸白茶,以传统加工工艺为对照,测定白茶中γ-氨基丁酸含量,并对白茶品质进行感官审评。结果表明:9个品种按真空厌氧技术加工的白茶,γ-氨基丁酸含量在1.82~3.64 mg/g之间,与传统工艺有显著极差异(P0.01);真空厌氧处理后,丹桂品种白茶γ-氨基丁酸含量最高,达3.64 mg/g,霞浦春波绿次之,茗科1号(金观音)最低,只有1.82 mg/g,不同品种白茶γ-氨基丁酸含量差异显著。感官审评结果表明,福鼎大毫白茶总分82.25,得分最高,品质最优,紫牡丹、茗科1号、九龙袍次之,春波绿得分最低。综合γ-氨基丁酸含量和品质指标,福鼎大毫是最佳的品种,其次是紫牡丹。     

鲜叶原料及造型方法对水仙有机白茶品质的影响探讨

为较好地控制和稳定大用水仙有机白茶的工艺和产品质量,分别以鲜叶采摘季节、批次、嫩度及干茶外形为观测因素开展单因素两水平对比试验,对不同处理的水仙白茶样品分别进行感官审评和主要品质成分分析,结果表明:制作水仙白茶以春季为好,鲜叶采摘宜早不宜迟,采摘标准以一芽一叶梢为佳,制作成白茶饼并不会明显降低茶叶品质,且较有利于降低白茶茶汤浓度和苦涩味,而鲜叶的嫩采比模压制饼更能保证干茶耐泡。总之,选用鲜嫩的原料对于提升水仙有机白茶的品质和饮用效率是最重要的。     

不同海拔及管理模式对白茶品质的影响研究

通过分析福建省福鼎市不同海拔及管理模式茶园采制的白茶样内含物检测及感官审评结果，结合茶园土壤理化性质、有机碳组分和碳库管理指数测定结果，阐明了不同海拔及管理模式下土壤性质对茶叶品质的影响。研究结果显示，中、高海拔茶园土壤持水能力和肥力均比低海拔茶园提高；对比普通管理模式，有机管理模式有更好的土壤条件供茶树生长；理化成分检测和感官审评结果显示，低海拔地区白茶多酚类物质较少，清香凸显；随海拔升高，白茶甜花香显，风味好；有机管理模式更是赋予了白茶浓郁的蜜韵。本研究为福鼎市茶树种植区域的高效利用和茶叶品质改良提供参考。     

补光萎凋对武义白茶品质影响研究

萎凋是白茶品质形成的关键工序,本试验对武义白茶萎凋叶设置不同补光处理,检测萎凋过程中在制品色泽、儿茶素组分、氨基酸总量和咖啡碱等理化成分,并对成品茶样进行感官审评,分析补光萎凋对武义白茶品质的影响,以期为武义白茶加工提供理论指导。     

高档红条茶适制品种筛选研究

通过感官审评与理化成分分析,对碧香早、尖波黄13号、桃源大叶、保靖黄金茶1号、槠叶齐、福鼎大白茶等6个品种加工的高档红条茶进行品质比较分析。结果表明,保靖黄金茶1号具有明显的品质优势,审评总分最高,尖波黄13号、碧香早、槠叶齐亦表现优秀。     

浅析福建乌龙茶感官审评检验

乌龙茶是福建极具特色的茶类产品,其感官品质至关重要。福建乌龙茶感官审评检验是利用评茶员的视觉、嗅觉、味觉、触觉等感觉器官,通过标准的评茶程序,来确定茶叶的感官品质特征及优劣。本文通过审评八项因子分析探讨乌龙茶的条索、色泽、匀整度、净度、香气、汤色、滋味、叶底,以提升福建乌龙茶感官审评技术水平,对乌龙茶感官品质作出科学准确判定具有重要意义。     

Analysis of nutritional components of eight famine foods of the Republic of Niger

In the western Sahel, indigenous plants become important staples when cereal harvests are inadequate to support populations inhabiting that region of Africa. The purpose of this study was to assess the nutrient content of several of these edible wild plants. The leaves of the following seven plant foods were analyzed: Ziziphus mauritiana, Cerathotheca sesamoides, Moringa oleifera, Leptadenia hastata, Hibiscus sabdarifa, Amaranthus viridi, and Adansonia digitata. The fatty acid, vitamin E, carotenoid, selected mineral and amino acid contents of these plant foods were determined. These same analyses were performed on the fruit of the Adansonia digitata. In quantitative and qualitative terms, Amaranthus viridis was found to be an excellent source of protein. Its amino acid composition compared favorably to that of a World Health Organization (WHO) protein standard. It also contained considerable amounts of the two fatty acids that are essential in humans (linoleic and -linolenic) and a number of minerals including iron, magnesium, calcium and zinc. The leaves of Hibiscus sabdarifa contained an appreciable quantity of protein the composition of which was comparable to the WHO standard. The mineral content of the leaves of this plant was also exceptionally high; noteworthy was its high zinc content. H. sabdarifa also contained significant quantities of the two essential fatty acids. Ziziphus mauritiana was an excellent source of the essential fatty acid linoleic acid and several of the metals including iron, calcium, magnesium and zinc. Its content of other essential nutrients, however, was rather low. In general, Adansonia digitata leaves were nutritionally superior to the fruit of the tree; however, the fruit did contain useful quantities of potassium, phosphorus, zinc and -linolenic acid. The Leptadenia hastata leaves were an especially good source of lutein and -carotene. These data should be useful to the people who inhabit the western Sahel in helping them devise healthy diets during times when cereal staples are in short supply.     

狗牙根诱变后代抗寒性评价

通过电解质外渗法和匍匐茎恢复试验对‘阳江’狗牙根及其12个通过形态鉴定选出的坪用价值高且花序密度低的诱变后代进行抗寒性鉴定。电解质外渗法结果表明:诱变后代间的抗寒性具有较大差异,其叶片半致死温度(LT₅₀)的变异范围为-7.6～-0.2℃(最低值与最大值相差7.4℃);参试材料抗寒性由强到弱依次为M18>M4>M26>M28> M22>阳江>M29>M31>M10>M37>M16>M1>M25,其中,有5个诱变后代抗寒性优于亲本,分别是M18、M4、M26、M28、M22。匍匐茎恢复实验结果表明:诱变后代M1、M22、M26、M31、M25在0℃和-5℃低温胁迫后的恢复生长率都高于亲本,恢复能力均优于亲本;M10、M37、M28在-5℃低温胁迫下,恢复生长能力低于亲本,抗寒性相对较弱,M16和M4在0℃和-5℃低温胁迫下,恢复生长率都低于亲本,抗寒性明显弱于亲本。综合2种方法鉴定结果显示:诱变后代M1、M25的恢复能力较强;M4、M28的叶片抗寒性较好,青绿期较长;M22、M18、M26的叶片抗寒性和匍匐茎恢复能力均较强;M29,M31的叶片抗寒性和匍匐茎恢复能力与亲本相似;M10、M16、M37的叶片抗寒性和匍匐茎恢复能力均较弱,整体抗寒性较弱。     

芦笋枯萎病病原鉴定

对造成福建省漳州市东山县的芦笋枯萎病病原菌进行分子鉴定,以期确定病原菌的属、种名,为防治该病害寻求理论依据。试验对分离纯化的病原菌核糖体DNA的ITS区进行测序,在Genbank中搜索其同源性并构建它们的系统发育树,结果表明：引起芦笋枯萎病的病原菌是镰刀属中的尖孢镰刀菌(Fusarium oxysporum),且病原菌之间的同源性高达89%,遗传差异不显著。     

Size and frequency of occurrence of pre-roost gatherings of starlings

One hundred and fifty-six pre-roost gatherings of starlings were observed at 28 sites around a roost in west Norfolk during winter. Pre-roost gatherings occurred more frequently at individual farmyards compared with individual fields, but 82% of the sites where gatherings occurred were on fields. The size of gatherings was greater, the closer to the roost. Birds in pre-roost gatherings on fields of autumn-sown winter wheat spent most of the time feeding and had a diet composed almost exclusively of wheat seeds. Birds in gatherings on grass fields also fed intensively whereas only 31% of birds at farmyards were feeding. The implications that these results have with regard to potential damage to fields of winter wheat and around farmyards are discussed.     

橡胶树丛枝病病原的抗血清制备与应用

以感染橡胶树丛枝病病原的长春花为材料,制备得到橡胶丛枝病病原菌抽提液,以抽提液为抗原免疫家兔,制备抗血清,经微量沉淀测定,抗血清效价为１：２０４８。应用橡胶丛枝病抗血清检测橡胶褐皮病,无症苗木检出率达３０％－３７％,可疑的褐皮病树检出率达８５．７％。     

农杆菌注射法瞬时转化荔枝果实组织的研究

为了寻找一种高效的荔枝果实瞬时基因表达方法,本研究以荔枝品种‘新球蜜荔’（Litchi chinensis Sonn. var. ‘Xinqiumili’）为试材,利用农杆菌注射法对荔枝果实组织进行转化,研究了果实发育时期、菌株种类、注射部位、取样时间、菌液浓度等对转化效率的影响。结果表明：选择果肉已完全包裹种子的Ⅱb期果实进行连体注射,在果柄、果皮、种子、果肉分别注入OD₆₀₀值为2.4的农杆菌菌株GV3101,4 d后取样进行检测,4个组织的GUS染色率较高。本研究成功建立了适用于荔枝果实的基因瞬时表达系统,为今后快速鉴定荔枝果实相关基因功能提供了基础。     

《生物安全法》实施背景下基因编辑技术的安全评价与监管

2020年10月17日,《中华人民共和国生物安全法》(以下简称《生物安全法》)通过全国人大常委会的审议,自2021年4月15日起施行.生物技术的研究与应用安全是《生物安全法》涉及的主要内容之一,基因编辑作为近几年生物技术领域的研究热点,其安全性评价和监管备受关注.本文概述了基因编辑技术的应用现状,比较了不同国家对基因编...     

蝉拟青霉疏水蛋白PChyd基因表达模式分析及敲除载体构建

为深入研究昆虫病原真菌蝉拟青霉疏水蛋白PChyd基因的功能,根据蝉拟青霉基因组信息克隆疏水蛋白PChyd基因,对该基因序列进行生物信息学分析,使用qRT-PCR技术对其在不同培养条件或阶段下的表达模式进行分析,并通过酶切酶连的方法构建了该基因的敲除载体。结果表明：PChyd基因的开放阅读框序列全长303 bp,编码100 aa,包含22 aa的信号肽序列和70 aa疏水蛋白功能区域。系统发育分析显示该基因与粗糙虫草菌亲缘关系最近。qRT-PCR结果显示PChyd基因在PDA培养的菌丝体、诱导的附着胞、诱导的芽生孢子中表达量显著高于另外2个样品,其中芽生孢子表达量最高,暗示该基因在蝉拟青霉侵染初期和在昆虫血腔中定殖阶段可能具有重要作用。凝胶电泳结果表明,成功构建了该基因的敲除载体,扩增出含有上臂、HPH、下臂的3356 bp左右的片段。本研究为进一步探究蝉拟青霉疏水蛋白PChyd基因的致病机理、生防工程菌的改造奠定了基础。     

波罗蜜叶片突变体叶绿素含量测定和超微结构观察

波罗蜜（Artocarpus heterophyllus）是一种热带果树,至今对其突变体的研究少有报道。本研究以波罗蜜叶片为试验材料,探究其叶片出现白化和返绿现象的可能原因。（1）用分光光度计法、比色法测定波罗蜜叶片突变体和正常绿叶的叶绿素及叶绿素前体物质含量;（2）用叶绿素酶Elisa试剂盒测定叶绿素酶活性;（3）用透射电子显微镜对叶绿体的超微形态结构进行观察。研究结果表明：（1）不同叶色所产生的叶绿素a含量、叶绿素b含量、叶绿素总含量、类胡萝卜素含量均存在显著差异;（2）波罗蜜叶片突变体和正常绿叶的叶绿素合成前体物质含量之间并没有出现显著性差异;（3）对波罗蜜叶片的叶绿素酶活性进行测定时,发现其活性出现显著差异,但对其叶绿素含量的差异性并没有产生较大影响;（4）观察波罗蜜叶片内叶绿体超微形态结构时,发现正常绿叶的叶绿体形态完好且数量较多,白化叶和返绿叶的叶绿体内部结构存在缺陷,其原因是叶绿体基粒构建阶段受阻;基于测定波罗蜜叶片中的叶绿素、叶绿素前体物质含量和叶绿素酶活性,并观察波罗蜜叶片内叶绿体的超微形态结构,对得到的数据结果进行比较分析。本研究推测是在叶绿素合成阶段,原脱植基叶绿素合成叶绿素时受阻及叶绿体发不良导致波罗蜜出现白化和返绿现象,为今后进一步综合研究波罗蜜突变体提供理论依据。     

Mechanism of action of insecticidal secondary metabolites of plant origin

Insect pest management is facing the economic and ecological challenge worldwide due to the human and environmental hazards caused by majority of the synthetic pesticide chemicals. Identification of novel effective insecticidal compounds is essential to combat increasing resistance rates. Botanicals containing active insecticidal phytochemicals appear to be promising to address some of these problems. Therefore, there is a continuous need to explore new active molecules with different mechanisms of action. Secondary metabolites present in plants apparently function as defense (toxic), which inhibits reproduction and other processes. The phytochemical biomolecules could be used for maximizing the effectiveness and specificity in future insecticide design with specific or multiple target sites, while ensuring the economic and ecological sustainability. In this article, the current state of knowledge on phytochemical sources and insecticidal activity, their mechanism of action in insects, resistance, and promising advances made in phytochemical research are reviewed.