激光扫描共聚焦显微镜的基本原理及其使用技巧

介绍了激光扫描共聚焦显微镜(laser scanning confocal microscopy,LSCM)的原理和构造,分析了LSCM的优点和缺点,并以花粉为例,详细介绍了共聚焦针孔直径、光电倍增管检测器增益、激光强度、扫描速度、扫描方式和Z轴步距等重要参数设置对共聚焦成像的不同影响。探讨了正确使用LSCM的方法与技巧,如获取高质量的图像、图像保存及图像处理,以便为科技人员利用LSCM开展更多植物学与环境科学相关的研究提供参考。     

Evaluation of Siberian Apricot (<Emphasis Type="Italic">Prunus sibirica</Emphasis> L.) Germplasm Variability for Biodiesel Properties

The potential for using Siberian apricot (Prunus sibirica L.) seed kernel oil as a source of biodiesel raw material is often overlooked when considering Siberian apricots as a greening tree in China. The aim of this research was to study and compare the oil content and fatty acid composition of 17 germplasm accessions in northern regions of China. Oil content ranged from 44.73 to 57.83 % with a mean of 50.18 % for the 17 accessions. In AS-080, AS-013, AS-017 and AS-027, oil contents were higher than 55 %. Percentages of fatty acids varied greatly among different accessions, but all the accessions contained high amounts of important oleic acid. The biodiesel properties of the Siberian apricot seed kernels oil methyl ester were determined and compared to the relevant specifications from the ASTM D6751-2003, EN 14214-2005 and GB/T 20828-2007. In general, germplasm accession PS-80 has been identified as the ideal feedstock for biodiesel production while germplasm accessions PS-17 and PS-27 were found to be the promising feedstock for biodiesel production.     

1-MCP对桃果实低温贮藏期间挥发性物质的影响——主成分分析法

以大久保桃果实（Prunus persica （L.） Batsch cv.Okubao）为试材,采用固相微萃取与气相色谱-质谱联用技术,对8℃贮藏期间对照组与1-MCP处理组的大久保桃果实挥发性物质进行测定,并使用主成分分析法确定大久保桃果实挥发物的指纹图谱及标志性挥发物.结果表明,大久保桃果实挥发性物质共检测到26种,主要包括酯类、芳香烃类、醛类、内酯类、缩醛类物质.8℃贮藏期间,1-MCP处理显著推迟了醛类和内酯类物质的释放高峰的出现,并且显著抑制了内酯类物质的释放量;在贮藏后期显著促进了乙醇的释放.主成分分析结果表明,2,2-二异丙基-1,3-二恶茂烷和1,1′-双（1,1,2,2-四甲基-1,2-亚乙基）苯是贮藏3 d时1-MCP处理组的标志性挥发物,而乙醇、丙酮、氰基乙酸是贮藏16 d和20 d时处理组的标志性挥发物.     

采后高CO2处理对板栗褐变相关因子的影响

以‘燕红’板栗为试材,研究了高CO2处理对板栗褐变相关因子的影响效果。将20kg板栗置于大玻璃瓶中,连续通入40%～50%CO2、3%～5%O2的气体在20℃下分别处理3d和5d。处理结束后,将其放置在常温20℃下于货架期第0、5、10d分别取样,测定板栗褐变相关因子的变化。研究结果表明,高CO2处理3s可有效减轻板栗的褐变程度。高CO2处理的板栗三部分的单宁含量均显著地降低,子叶缝合面和中间层后期差异不显著。总酚含量在子叶表层处理显著低于对照,但在子叶缝合面和中间层刚处理完含量要高于对照,后期差异不显著。处理有效地降低了三部分的PPO活性,且在整个货架期中PPO一直保持一个较低的水平。处理在货架期前5d里,显著地降低了POD活性,后期这种差异消失。处理还有效地降低MDA的生成量,处理3d的MDA含量显著地低于对照,较好地保持了膜系统的完整性。综合各指标考虑,高CO2处理3d控制褐变的效果好于处理5d。     

Characterisation of oil oxidation,fatty acid,carotenoid, squalene and tocopherol components of hazelnut oils obtained from three varieties undergoing oxidation

Hazelnut oils obtained from three varieties of Chinese hybrid hazelnuts (cv. ‘Liaozhen 3 (LZ)’, ‘Pingou 21’ (PG) and ‘Yuzhui’ (YZ)) were used to compare the lipid oxidation characteristics (peroxide value, p-anisidine value and conjugated diene value), fatty acid profiles and major active components (squalene, carotenoids and tocopherols) under oxidation condition at 60 °C for 40 days, in addition, the molecular structure changes in the three hazelnut oils were monitored by Raman spectroscopy. The lipid oxidation of the three hazelnut oils had similar tendencies, and the oxidation rate was slower in the early stage and faster in the later stage. Polyunsaturated fatty acids (PUFAs) tended to decrease mainly due to the decrease in linoleic acid. LZ had higher contents of tocopherol, carotenoids and PUFAs than the other varieties, while YZ owned the highest content of squalene. Tocopherol and carotenoids of the three hazelnut oils showed easy loss, while squalene was relatively stable. Raman spectroscopy can effectively indicate the degree of oxidation and carotenoid levels of hazelnut oil. This study can provide a scientific basis for variety selection in planting and utilisation of active ingredients for the hazelnut industry.     

生长调节剂DA-6和DCPTA处理对冬枣果实发育过程中活性氧及其相关生理指标的影响

研究采前己酸二乙氨基乙醇酯(DA-6)和2-(3,4-二氯苯氧基)-乙基-二乙胺(DCPTA)喷施处理对冬枣发育期果实活性氧代谢的影响。试验于盛花期、盛花后20d和40d进行DA-6、DCPTA的喷施树冠处理,并在冬枣果实发育过程中定期取样进行活性氧及其相关生理指标的测定。结果表明：采前DA-6和DCPTA喷施处理后,对O2－ ·的产生速率没有显著影响,仅提前了其低谷的产生;DA-6处理冬枣果实的H2O2含量显著高于DCPTA处理;与对照相比,两处理在整个发育期内显著提高了冬枣果实的SOD和PPO的活性;DCPTA处理显著提高冬枣果实发育末期的CAT活性而DA-6处理显著抑制了冬枣果实的CAT活性,同期DCPTA处理抑制了MDA含量。     

不同温度下1-MCP与水杨酸处理对李果实品质影响的主成分分析

探讨不同温度下采后1- 甲基环丙烯(1-MCP)、水杨酸(SA)及二者复合处理对“安哥诺”李果实品质的影响。结果表明：1-MCP 及其与SA 的复合均可延缓李果实20℃与0℃贮藏及货架时期的硬度下降;而不同处理对李果实色度、可溶性固形物(SSC)、pH 值及蛋白质含量的作用效果受贮藏温度及贮藏时间影响比较显著。主成分分析结果显示,硬度及色泽可显著区分李果实0、20℃贮藏以及货架期的品质;20℃贮藏时,1-MCP、SA 与1-MCP+SA处理对李果实的影响主要表现在提高SSC,对李果实色泽比的影响在贮藏18d 后也较为显著;0℃贮藏104d时,各处理对李果实SSC 的影响最为显著。通过主成分分析构建的综合评价模型可知,1-MCP 提高0℃贮藏及货架期期间李果实的综合品质,1-MCP+SA 则显著延缓了20℃贮藏及货架期期间李果实品质劣变。     

纳米纤维素发光材料研究进展

纳米纤维素发光材料不仅具有发光基团特有的光物理或光化学性能,还具备纳米纤维素的可生物降解、生物相容、环境友好等特性,拓展了功能化纤维材料的应用领域.根据制备方法,纳米纤维素发光材料可分为三类:纳米纤维素/碳量子点复合发光材料、纤维素发光碳量子点和纳米纤维素/荧光染料复合发光材料.纳米纤维素发光材料具有独特的光学特性及结...     

紫外照射处理对蒜薹品质与活性氧代谢影响的多变量解析

运用多变量分析方法探讨紫外照射处理对蒜薹品质与活性氧代谢的影响。采后常温贮藏过程中,蒜薹的呼
吸强度上升,光泽降低、颜色泛黄,导致蒜薹的品质降低,紫外照射处理加速了蒜薹劣变过程,其中处理15 min的
效果最显著。主成分分析发现,a*、b*是影响紫外照射处理对蒜薹劣变作用的主要品质指标,过氧化氢（H2O2）含
量、超氧化物歧化酶（SOD）活性、丙二醛（MDA）含量、多酚氧化酶（PPO）活性、总酚、花青素、谷胱甘肽
（GSH）含量是主要决定指标。相关性分析、偏最小二乘分析和通径分析的结果都表明：H2O2含量与SOD活性呈显
著正相关,与总酚含量呈显著负相关;可食率与DPPH自由基清除能力呈显著正相关,与GSH、MDA和花青素含量
呈显著负相关。