1-MCP结合冰温贮藏对葡萄果实质地的影响

为探讨1-MCP处理结合冰温贮藏对采后葡萄果实质地的影响,以乍娜葡萄为试材,应用质构仪质地多面分析( TPA)方法对葡萄贮藏期间果肉质地参数变化规律进行研究.结果表明,1.0μ.L/L 1-MCP处理结合冰温贮藏可以延缓葡萄果实的软化,果实的硬度、弹性、凝聚性和咀嚼性较之单纯的冷库和冰温贮藏均有所提高;果肉硬度与回复性呈较好的正相关性,果肉弹性与果肉回复性、咀嚼性、凝聚性均呈现较好的相关性;葡萄好果率与果肉硬度在一定范围内呈良好线性关系.结果也表明,TPA测试能够较好地反映葡萄贮藏期间果实质地的变化,适用于葡萄贮藏品质的客观评价.     

我国甜菜育苗移栽机械的研究进展和发展趋势

甜菜育苗移栽是一项高产栽培技术,但我国的推广面积却仅有12%.育苗移栽机械只有与我国甜菜生产相适应,才能促使育苗移栽技术顺利大面积推广.为此,回顾了我国近30多a来所研制的甜菜育苗移栽机械(包括碎筛土机、床土配制机、墩土机和移栽机)的研究进展,详述了各自的结构形式、工作原理和技术参数,分析了工作特点和优缺点;针对我国甜菜育苗移栽机械未能推广应用的现状,分析了存在的问题,提出了相应的建议,并预测了未来的发展趋势.     

利用近等基因系研究豌豆铁蛋白基因对水稻重要生物学特性的影响

为研究外源豌豆铁蛋白基因(Pea-Fer)导入水稻后对受体重要生物学特性的影响,本实验以原始受体亲本粳稻(Oryza sativa ssp.japanica)品种秀水11为轮回亲本,外源豌豆(Pisum sativum)铁蛋白转基因纯系Fer34为非轮回亲本,采取连续回交,结合gus标记基因辅助选择技术,在BC6F3获得含Pea-Fer的Fer34-XS11,它与秀水11构成一对近等基因系。结果显示,(1)Pea-Fer导入显著提高了水稻籽粒中的铁元素含量,但对镁、钙、锰和锌等元素的积累作用影响不大;(2)Pea-Fer导入对种子发芽特性和苗期植株生长速率无显著影响;(3)Pea-Fer导入没有改变成株叶片光合色素的含量和组成,但一定程度上提高了植株的净光合速率;(4)Pea-Fer导入对水稻的成熟期农艺性状及经济性状均无不良影响。外源豌豆铁蛋白基因的导入除使水稻籽粒的铁含量有明显增加外,研究结果表明对水稻其它重要生物学性状并无明显负作用,这为开展富铁水稻新品种培育提供了依据。     

大鼠肌肉卫星细胞的分离、鉴定与诱导分化

肌肉卫星细胞是组织特异性干细胞,负责着骨骼肌的生长和再生.尽管发现卫星细胞的存在已经有50多年的历史了,但分离鉴定肌肉卫星细胞的方法仍然不稳定.本研究使用两步酶消化和差速贴壁相结合的方法分离大鼠(Rattus norve gicus)肌肉卫星细胞.免疫细胞化学染色显示,分离的大鼠肌肉卫星细胞高表达Desmin;通过RT-PCR鉴定所分离的细胞表达肌源性干细胞因子Myf5及Myod1;成肌诱导48h后,卫星细胞开始形成多核的肌管;成脂诱导1周后,细胞内开始出现脂滴,2周后充脂细胞明显增多.研究结果提示,分离的卫星细胞具有肌源性,有发育形成肌管和向成脂细胞分化的能力.     

Comparison of biological parameters between the invasive B biotype and a new defined Cv biotype of <Emphasis Type="Italic">Bemisia tabaci</Emphasis> (Hemiptera: Aleyradidae) in China

The sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a widely distributed and destructive agricultural pest on various host plants. The biology of two biotypes of B. tabaci: the invasive B and a new defined Cv biotype, on a range of host plants (hibiscus, laurel, poinsettia, collard, cucumber and tomato) were studied in the laboratory. Results revealed that the developmental periods of the B biotype immatures were not significantly different on the tested host plants except those between laurel and collard. The Cv biotype immatures developed significantly slower on cucumber and tomato than on the other plants. B. tabaci B biotype had the highest survivorship on collard (68.55%), and the lowest on laurel (33.24%), while the Cv biotype had the highest and lowest survivorships on laurel (61.63%) and tomato (36.74%). Host plants did not significantly affect the pre-ovipostion period regardless of biotype. The longest averaged longevity and highest fecundity of B biotype were both recorded on collard: 25.15 days and 143.0 eggs. The highest fecundity of Cv biotype was 196.49 eggs on laurel and its longest longevity was on hibiscus (19.62 days). The intrinsic rate of natural increase (r _m) of B biotype on the three vegetables were all higher than those on the three ornamentals whereas the r _m of Cv biotype on the three ornamentals were all higher that those on the three vegetables. Our research indicates that B. tabaci B and Cv biotypes have different host plant suitabilities. The three tested vegetables were more suitable for B biotype while the three tested ornamental plants were more suitable for Cv biotype. The potential mechanism for the different suitability of B and Cv biotypes on various host plants is also discussed.     

Does tree seedling growth and survival require weeding of Himalayan balsam (Impatiens glandulifera)?

The effect of Himalayan balsam (Impatiens glandulifera) on survival and growth of naturally regenerated silver birch (Betula pendula) and planted Norway spruce (Picea abies) and silver fir (Abies alba) seedlings was studied in a weeding experiment over 3 years. Three different treatments were applied: control, mowing, and hand weeding by pulling out the entire plant. There were no consistent treatment effects on height and diameter of the tree seedlings. The coverage of Rubus fruticosus had a negative impact on diameter increment of Norway spruce and silver fir. As opposed to growth, treatment effects on seedling survival could be found for planted Norway spruce and silver fir. However, it is very likely that these effects, namely higher seedling survival after mowing, have to be attributed to the control of bramble (Rubus fruticosus) rather than to that of Himalayan balsam. It is concluded that Himalayan balsam is not able to seriously affect the growth of already established seedlings.     

棉花FAD 2-1基因的克隆及其ihpRNA和amiRNA干扰载体的构建

 采用RT-PCR方法克隆了棉花△-12脂肪酸去饱和酶基因(GhFAD2-1)的cDNA全长序列,该基因含有1158 bp的完整开放阅读框。棉花FAD2-1是种子中编码催化油酸形成不饱和脂肪酸的关键酶的基因,选取GhFAD2-1基因中的一段特异的515 bp片段,构建了种子特异性启动子NAPIN调控的ihpRNA干扰表达载体pFGC1008-NAPIN-FAD2-1,同时构建了针对GhFAD2-1基因的人工miRNA表达载体pCAMBIA1302- amiRNA-FAD2-1。     

Volatile constituents, inorganic elements and primary screening of bioactivity of black coral cigarette holders

Black corals (BC) have been used for a long time in Chinese medicine, and may have some pharmaceutical functions when used as material for cigarette holders in southeast China. This study is aimed to investigate the bioactivities of volatile constituents in BC and to explore the folklore behind the use of BC cigarette holders (BCCHs). We extracted the volatile constituents of BC by supercritical fluid extraction (SFE) with carbon dioxide (CO₂-SFE), then identified and analyzed the constituents by gas chromatography-mass spectrometry (GC-MS). In total, 15 components were reliably identified in BC and found to be biologically active. These included triethyl phosphate, butylated hydroxytoluene, cedrol, n-hexadecanoic acid, squalene, and cholesterol. Meanwhile 13 inorganic elements (P, Ca, Mg, S, B, Si, Fe, Cu, Zn, Ba, etc.) were determined by inductively coupled plasma spectrometer (ICPS). In the bioactivity tests, the BC extract (BCE) showed a scavenging activity of 2,2-diphenyl-1-picrylhydrazyl free radicals and hydroxyl radicals by phenanthroline-Fe (II) oxidation and moderate inhibition of Gram-positive microorganisms. The antioxidant and antimicrobial activities of BC, which are related to the active chemical composition, may explain the perceived benefit for cigarette smokers who use BCCHs.     

Rapid determination of estrogens in milk samples based on magnetite nanoparticles/polypyrrole magnetic solid-phase extraction coupled with liquid chromatography-tandem mass spectrometry

In this study, a nanocomposite of polypyrrole-coated magnetite nanoparticles (denoted as MNPs/PPy) was prepared and employed as magnetic solid-phase extraction (MSPE) sorbent for extraction of estrogens from milk samples. Because the polypyrrole coating possessed a highly π-conjugated structure and hydrophobicity, MNPs/PPy showed excellent performance for the estrogen extraction. Estrogens could be captured directly by MNPs/PPy from milk samples without protein precipitation. Moreover, the extraction could be carried out within 3 min. Thus, a rapid, simple, and effective method for the analysis of estrogens in milk samples was established by coupling MNPs/PPy-based MSPE with liquid chromatography-tandem mass spectrometry (LC-MS/MS). The limits of detections for estrogens investigated were in the range of 5.1-66.7 ng/L. The recoveries of estrogens (concentration range of 0.5-20 ng/mL) from milk samples were in the range of 83.4-108.5%, with relative standard deviations ranging between 4.2 and 15.4%.     

油缸在机床应用中若干问题的解决方法

针对油缸在机床应用中的一些问题,理论分析其发生的原因,并采取切实有效的手段,改进其性能,较好地解决了油缸的撞缸、速差、爬行、漏油、热变形等问题,创造了良好的经济效益。