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41.
旨在明确黑龙江大学呼兰校区甜菜立枯病的病原菌种类,为科学防治该病提供理论参考。以采自黑龙江大学呼兰校区的甜菜立枯病植株为试材,用形态学观察、致病性测定和分子生物学鉴定方法,依据柯赫氏法则,对病原菌进行分离和鉴定。结果表明,从发病甜菜幼苗根部上分离出的菌株L1,菌丝呈白色。大型分生孢子为镰刀型,有隔膜,小型分生孢子多为单细胞少数有隔膜。分子鉴定结果显示,该病原菌在基于ITS和tef1序列构建的系统发育树上与腐皮镰孢菌类群处同一分支。根据形态学和分子鉴定结果,确定引起黑龙江大学呼兰校区甜菜立枯病的病原菌为腐皮镰孢菌(Fusarium solani)。 相似文献
42.
A multiresidue method for determining pesticides in rapeseed, rapeseed oil, and rapeseed meal by use of liquid chromatography-tandem mass spectrometry is developed. Samples were extracted with acetonitrile or acidified acetonitrile and cleaned up by a 12 h freezing step. The recovery data were obtained by spiking blank samples at three concentration levels. The recoveries of 27 selected pesticides in rapeseed, rapeseed oil, and rapeseed meal were in the range of 70-118%, at the concentration level of 10 μg kg(-1), with intraday and interday precisions of lower than 22 and 27%, respectively. Linearity was studied between 2 and 500 μg L(-1) with determination coefficients (R(2)) of higher than 0.98 for all compounds in the three matrices. The limits of quantitation (LOQs) of pesticides in rapeseed, rapeseed oil, and rapeseed meal ranged from 0.3 to 18 μg kg(-1). The n-octanol-water partition coefficient showed more influence than water solubility in extracting pesticides by acetonitrile from matrices of high fat content. This method was successfully applied for routine analysis in commercial products. 相似文献
43.
B Gui YY Shim RS Datla PS Covello SL Stone MJ Reaney 《Journal of agricultural and food chemistry》2012,60(35):8571-8579
Cyclolinopeptides are a group of naturally occurring hydrophobic cyclic peptides found in flaxseed and flax oil that have immunosuppressive activity. This study describes the measurement of flaxseed cyclolinopeptide concentrations using an internal standard HPLC method. In addition, the concentration of cyclolinopeptides in the seed of Canadian flax cultivars grown at two locations over two years is reported. The data are consistent with the formation of flaxseed cyclolinopeptides from two ribosome-derived precursors. Each precursor protein includes the sequences corresponding to three cyclolinopeptides from which those cyclolinopeptides are presumably derived by precursor processing. The concentrations of cyclolinopeptides C and E, which are encoded by the same gene sequence, are highly correlated, and the concentrations of cyclolinopeptides D, F, and G, which are encoded by a second gene sequence, are also highly correlated. The strong correlation between the cyclolinopeptides arising from the same gene may prove to be important in understanding how peptide concentration is controlled. Additional research may lead to approaches to improve flax either as a platform for peptide production or as a source of oil with improved drying properties and flavor. 相似文献
44.
wanggx@.com。 《勤云标准版测试》2006,(3)
从冬枣贮藏保鲜的方法和影响其贮藏保鲜的因素等方面,对冬枣贮藏保鲜技术研究现状进行了较为详细的论述。总体来看,冬枣贮藏保鲜的物理贮藏方法包括低温贮藏、气调贮藏和减压贮藏,化学方法中包括一些化学杀菌剂、保鲜剂和激素处理,考虑到化学药剂的残留对人体的影响,近几年来,科研人员逐步探索开发冬枣采后生物防治领域,并取得了一定的成绩;同时,也论述了影响冬枣保鲜效果的主要因素有冬枣自身因素、农业技术措施和环境条件等,并对当前研究工作存在的问题及今后的研究重点进行了讨论。 相似文献
45.
46.
采用原子吸收分光光度法和相关分析法对主要造林树种旱冬瓜体内各营养器官的
7种矿
质元素含量的分布规律、元素之间以及植物与立地土壤之间的相关性进行了研究。结果
表明,旱冬
瓜不同器官各元素含量有着显著的差异,K、Mg、Fe、Zn、Cu、Mn在叶片中含量最多,C
a在树皮中
含量最高;大多数元素在树干中含量最低。旱冬瓜对K、Ca、Mg、Zn、Cu有较强的吸收富
集能力,
对土壤富集系数大小依次为Mg>Ca>Cu>K>Zn>Mn>Fe,一般叶的富集系数最高。元素间和
元素与立地土壤的相关分析表明,K、Mg、Mn、Fe、 Cu之间有显著的相关性,Ca和Mn之
间的相关
性显著,除Fe元素外,植物体中K、Mg、Mn、Zn、Cu元素含量与土壤中元素含量关系相一
致。 相似文献
47.
为了将农业生态系统中广泛分布的丛枝菌根真菌(AMF)资源科学地应用于药用植物,本文对AMF分类、中国药用植物资源现状及AMF在药用植物上的应用分别进行了总结。AMF不仅能改善药用植物的营养水平,促进其生长;而且能促进药用植物体内萜类、甾体类及黄酮类等活性物质的合成与积累;此外,AMF对药用植物因连作引发的各种土传病虫害也表现出积极的生防作用。因此,AMF在药用植物栽培领域具有极大的应用潜力。同时,鉴于菌根专性共生的特性,提出了扩大与AMF共生的药用植物种类、AMF与其他有益微生物混合接种、共生体建成过程中土壤生态环境变化等尚待探究的问题,以期为该领域的深入研究提供借鉴与参考。 相似文献
48.
水轮机频繁经历变负荷工况转换过程,使得机组在较短时间内工作参数急剧变化,严重影响电站稳定运行。该研究以某贯流式水轮机为研究对象,在考虑自由液面和水体重力的情况下,采用动网格技术对贯流式水轮机相同出力范围下的减、增负荷过渡过程的动态特性进行分析。研究结果表明:由于增负荷和减负荷过渡过程的起始工况导致起始流动状态不同,因此在相同出力时,机组内的流动分布不同,减负荷过程尾水管内的涡流面积及强度明显小于增负荷工况,且尾水管涡带尺度也明显小于增负荷过程;相比于增负荷过程,减负荷过程中转轮叶片大范围的低压区极易引发空化;机组内的水压力脉动主要以尾水管涡带引起的0.1fn(fn为转频)低频压力脉动和转轮的旋转引起3fn的高频压力脉动为主,增负荷过程的压力脉动幅值明显大于减负荷过程,两种压力脉动共同作用,使得贯流式水轮机主要振动区域集中于转轮。研究结果对贯流式水轮机的设计与运行具有一定的指导意义。 相似文献
49.
Yingai Gui Wei Yu Xiangwu Ge Haiyan Li Chengpeng Sun Xiqin Mao Kuijing Yuan 《Journal of Pesticide Science》2022,47(1):1
Root exudates from Chinese celery (Apium graveolens) and Chinese cabbage (pak choi, Brassica chinensis) plants treated by prometryn, an herbicide, were qualitatively and quantitatively investigated and compared under hydroponic cultivation. Prometryn and its metabolites released into the nutrient solution were analyzed by ultra-performance liquid chromatograph coupled with orbitrap mass spectrometer to investigate whether this xylem-mobile herbicide is exuded from the roots. The results showed that celery and pak choi had different root exudation profiles. Celery metabolized prometryn to prometryn sulfoxide and released both compounds from the roots. In contrast, pak choi barely metabolized or actively released prometryn from the roots. The concentration of prometryn sulfoxide released from celery after 96 hr was 21 µg/L, which was nearly one-third that of released prometryn. Our results indicate that the root exudation and translocation of xylem-mobile herbicides could be significant in plants and are highly species dependent compared with phloem-mobile herbicides. 相似文献
50.
Zhi-qiang Li Dan Gui Zhi-hua Sun Jun-bo Zhang Wen-zhi Zhang Hui Zhang Fei Guo Chuang-fu Chen 《Journal of veterinary science (Suw?n-si, Korea)》2015,16(4):467-473
Brucellosis is a zoonotic disease that causes animal and human diseases. Vaccination is a major measure for prevention of brucellosis, but it is currently not possible to distinguish vaccinated animals from those that have been naturally infected. Therefore, in this study, we constructed the Brucella (B.) abortus 2380 wbkA mutant (2308ΔwbkA) and evaluated its virulence. The survival of 2308ΔwbkA was attenuated in murine macrophage (RAW 264.7) and BALB/c mice, and it induced high protective immunity in mice. The wbkA mutant elicited an anti-Brucella-specific immunoglobulin G response and induced the secretion of gamma interferon. Antibodies to 2308ΔwbkA could be detected in sera from mice, implying the potential for use of this protein as a diagnostic antigen. The WbkA antigen would allow serological differentiation between infected and vaccinated animals. These results suggest that 2308ΔwbkA is a potential attenuated vaccine against 16M. This vaccine will be further evaluated in sheep. 相似文献