大果水晶梨褐色果皮突变体木质素合成相关基因的组织特异性表达分析

为研究木质素合成相关基因(PAL1、PAL2、CAD、POD、4CL)在大果水晶梨褐色果皮突变体中的表达特性,并为研究梨褐色果皮形成机制奠定基础。按照RNA试剂盒法提取果皮、花、叶片、果肉、枝条韧皮部中总RNA;利用DNAMAN和Primer 5.0软件设计特异引物;使用实时荧光定量PCR技术研究基因的表达。结果表明,PAL1、PAL2、CAD、POD、4CL的最高相对表达量均出现在果皮中;果皮和果肉中POD的相对表达量极显著高于其他基因,花、叶片和枝条韧皮部中CAD的相对表达量极显著高于其他基因。综上所述,大果水晶梨褐色果皮突变体木质素合成相关的5个酶基因在果皮、果肉、叶片、花和枝条韧皮部中的表达具有明显的组织特异性,这些基因可能与大果水晶梨褐色果皮的形成关系密切。     

类黄酮及茶儿茶素生物合成途径及其调控研究进展

 类黄酮化合物是植物的次生代谢产物,广泛分布于植物界且具有较强的生物活性。儿茶素是主要的类黄酮化合物之一,其含量占茶树鲜叶干重的12%～25%。作为茶叶的主要风味物质,儿茶素还具有抗氧化、抗诱变与防癌、抗心血管疾病、抗紫外线辐射等功能。本文从类黄酮及茶儿茶素的生物合成途径、组织化学定位、合成调控措施等方面,综述有关茶树儿茶素的生物合成代谢及其调控的研究进展,旨在为茶儿茶素生物合成的基因调控、代谢工程提供新的思路。     

Behavior of arazá (Eugenia stipitata Mc Vaugh) fruit quality traits during growth,development and ripening

The period between fruit set and full ripening of arazá fruit grown in the Colombian Amazonia was 55 ± 5 days. Three stages of a sigmoidal growth were identified and longitudinal and equatorial traits fitted a logistic model better than three-degree polynomial models. Fruit growth clearly exhibited three different physiological stages, identified as follows: S1, involving cellular division during the first 14 days; S2, maximum fruit growth, during which cellular expansion took place (up to day 50), and a final S3 state of 5 days to reach physiological maturity. After this time, the fruit can be harvested with a dull green coloration. Parenchyma was the principal fruit tissue, and no support tissues (sclerenchyma or collenchyma) were evident. The respiratory pattern of arazá fruit was climacteric, with maximum respiration rates of around 200 mg CO₂ kg⁻¹ h⁻¹, preceded by a peak of ethylene production (20 μL C₄H₄ kg⁻¹ h⁻¹), a change in skin color from green to yellow, a total soluble solids value of 5°Brix, an increase in the sucrose and fructose content up to 2.8 μmol g⁻¹, a pH which increased to 3 units, and a decrease in titratable acidity to 400 mmol H⁺ L¹⁻. Malic acid was the main organic acid in the edible pulp and ascorbic acid was present in a concentration of 17.8 μmol g⁻¹. Skin color (as measured by hue angle) combined with titratable acidity and fruit firmness can be recommended as harvest indices for arazá fruit.     

10种药用植物萜类合酶(DXS)生物信息学分析

为研究药用植物DXS酶的性质及其结构功能,利用生物信息学方法对GenBank中青蒿、砂仁、铁皮石斛等10种药用植物DXS编码氨基酸序列的理化特性、系统发育进化、亲/疏水性、亚细胞定位、磷酸化位点、二级结构、信号肽、跨膜结构、功能域等进行分析和预测。结果表明：不同植物DXS酶氨基酸序列的理化性质基本一致;在进化关系上可划分为2类;DXS酶蛋白主要表现为亲水性蛋白;大多数定位于叶绿体,少数定位于线粒体;丝氨酸磷酸化位点占据主导地位;α-螺旋是DXS多肽链中大量的结构元件,散布于整个肽链中;除了铁皮石斛具有1个信号肽,其余DXS氨基酸序列不具有信号肽,可推测出DXS可能不是分泌性蛋白;没有跨膜结构域;具有3个功能域分别为TPP_superfamily、Transket_pyr_ superfamily和Transketolase_C superfamily。研究结果将为DXS的酶学特性及萜类生物合成的分子机理研究提供理论参考。     

胚乳突变体在水稻淀粉合成调控研究中的作用

淀粉作为稻米最主要的储藏物质,其含量、结构及其特性影响水稻的产量和品质。随着分子生物学的不断发展,通过筛选胚乳突变体,克隆了大量调控水稻淀粉合成相关的基因,使淀粉生物合成的机理也逐渐清晰。本文综述了水稻淀粉结构、淀粉生物合成,以及淀粉突变体,包括糯性、高直链淀粉、垩白、粉质、暗色、糖质、皱缩等突变体的突变基因克隆及功能研究最新进展,以期为进一步阐明水稻淀粉生物合成的途径,以及优质水稻新品种的培育提供参考。     

GA3和乙烯利处理对杏花败育的影响

以黑龙江 657( HL657)、意大利 7号 ( Italy7)、大曹杏和实生 1 9号杏品种为试材 ,对各品种不同结果枝类型以及不同树冠部位的杏花败育率调查 ,并在休眠、萌芽、花蕾期喷 GA3 、乙烯利 ,统计各品种杏花雌蕊败育率及花粉活力情况。结果显示 :杏花雌蕊败育率与品种有很大关系 ,杏栽培品种长果枝败育率最高 ,中果枝次之 ,短果枝最低 ;树冠上部杏花败育率较树冠中部及下部低 ;GA3 处理增加了杏花败育率 ,并使花粉活力提高 ;乙烯利处理可促使杏花雌蕊败育率降低 ,但同时也降低了花粉活力     

Evaluation of the effect of dietary sesamin on white muscle lipid composition of common carp (Cyprinus carpio L.) juveniles

This study was focused on the clarification of the effect of dietary sesamin on fatty acids and the composition of different lipid fractions [phospholipids (PLs), cholesterol and triacylglycerols] in the white muscle of common carp (Cyprinus carpio L.) juveniles. Two different basic diets with defatted fishmeal as a protein source and either only linseed oil or a mixture of linseed and sunflower oil as a lipid source designed to have two different n‐3/n‐6 ratios (1.21 – CL group; 0.32 – CM group) were produced. Each diet was then used with or without added sesamin (0.58 g 100g^?1). One hundred and forty‐four individuals were fed in triplicated groups for 63 days until their weight had doubled. No influence of dietary sesamin on growth, mortality or on the white muscle lipid content of the fish was found. Added sesamin significantly decreased the content of PLs and increased the cholesterol content in the CM group. No effect was found in the total lipid fatty acid composition but there was found a significantly lower content of saturated fatty acids and 20:5n‐3 in PLs and of 22:6n‐3 in triacylglycerols in the sesamin supplemented CL group. These and other differences show either a tendency of lower long chain n‐3 fatty acids biosynthesis or their higher use in β‐oxidation in sesamin‐supplemented groups. We conclude that sesamin in this experiment had no substantial positive impact on the lipid metabolism of juvenile carp.     

瓜叶菊花青素合成关键结构基因的分离及表达分析

 本文通过RT-PCR的方法分离了花青素合成途径上的关键结构基因片段：CHS、CHI、F3H、F3'H和DFR。在白色系、红色系、紫色系和蓝色系瓜叶菊舌状花中,采用半定量RT-PCR的方法分析CHS、CHI、F3H、F3'H、DFR、F3'5'H、3MaT这7个结构基因在花不同发育阶段的表达模式。结果表明：在白色花中,不存在CHS的表达;在红色花中,检测到F3'H基因的高丰度表达,但没有检测到F3'5'H的转录本;在蓝色花中,没有F3'H表达的信号,但在花序开放的第Ⅰ阶段有较强的F3'5'H的表达信号;而在紫色花中,可以同时检测到F3'H和F3'5'H的转录本。此外,瓜叶菊花青素合成相关结构基因在花序开放初期高丰度表达,随后逐渐降低,在第Ⅳ阶段表达量再次出现升高现象,而在花序开放末期表达量极低或没有表达信号。     

温度对采后梨果实多胺,ACC含量,EFE活性和乙烯生成量的影响

测定了两个日本梨品种菊水和二十世纪在３０、１５和５℃贮藏温度下，多胺，ＡＣＣ含量、ＥＦＥ活性和乙烯释放速率的变化，１．１５和５℃低温可显著抑制梨果实内ＥＦＥ活性，乙烯生成速率显著降低；２．两品种对低温的敏感性存在差异，１５℃低温处理既能减少二十世纪梨的乙烯生成速率，也能抑制乙烯释放高峰的出现，而同样的温度处理仅能减少菊水梨的乙烯生成速率，不能抑制乙烯释放高峰的出现；３．在１５和５℃处理下，两品种果     

外源多胺和乙烯对小麦籽粒品质的影响

以‘西农538’和‘周麦22’为材料,在灌浆期分别喷施亚精胺(Spd)、腐胺(Put)和乙烯(Eth),研究外源多胺和乙烯对小麦籽粒品质的影响。结果表明:灌浆期喷施Spd,2个品种籽粒的清蛋白、醇溶蛋白、谷蛋白和总蛋白相比对照均有所提高,面筋质量分数、沉降值等加工品质指标均有不同程度的上升趋势,直链淀粉质量分数下降但未达显著水平,小麦品质得到改善。而喷施Put的效果相反但未达到显著影响。Eth提高清蛋白和球蛋白质量分数,但显著降低醇溶蛋白和谷蛋白质量分数以及面筋质量分数、沉降值等加工品质指标。说明通过化学调控等途径增加籽粒Spd浓度或降低Put和Eth浓度,可以在一定程度上改善小麦的籽粒品质。