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1.
采用不同浓度营养液浸泡丙烯酰胺-丙烯酸盐(钾)共聚交联物(CAA),与蛭石混合配制成5种基质,研究不同基质对黄瓜穴盘苗的生长、叶绿素荧光参数、光合作用的影响。结果表明:随营养液浓度的增加,黄瓜幼苗的生长指标显著提高,净光合速率(Pn)、最大光化学效率(Fv/Fm)等光合作用指标显著增加;在5种基质处理中,处理5(总盐分浓度为10.98 g/L)效果最明显,幼苗生长指标、光合参数等均显著高于其它处理;表明使用高浓度营养液浸泡CAA与蛭石混合配制的育苗基质进行黄瓜育苗,既可以减少施肥次数,还能显著提高黄瓜的穴盘苗质量,可作为生产中草炭为主的栽培基质的替代品。 相似文献
2.
Tong Mingchu 《保鲜与加工》1989,(4)
This paper presents a simple and efficient engineering design method of series-parallel correction for canonical system type 2 and gives a practical design example.The following and anti-disturbance performances of
the system by means of digital simulation are analyzed.The performance indexes in different design parameters are listed.This paper is available for reference in engineerng design. 相似文献
3.
马铃薯挖掘铲计算机辅助分析与模拟试验研究 总被引：2，自引：3，他引：2
针对马铃薯挖掘铲工作阻力大这一难题，采用参数化特征造型软件Inventor进行挖掘铲虚拟设计，基于土壤与铲体作用动力学分析，建立了挖掘铲牵引阻力数学模型。通过计算机辅助分析(Computer Aided Analysis，CAA)手段，使用Visual Basic语言编程实现了挖掘铲牵引阻力与前进速度、铲面倾角、挖掘深度、工作幅宽等主要影响因素的模拟试验，最终确定了挖掘铲设计参数，并在虚拟装配体中进行参数调整改进模型。土槽台架试验结果与计算机模拟试验结果基本吻合，验证了CAA过程和模拟试验的有效性，田间收获试验结果显示马铃薯收获质量达到了设计要求，验证了挖掘铲几何参数的合理性。研究结果为其它农机具研究设计提供了一种参考。 相似文献
4.
Ulrich Gisi Helge Sierotzki 《European journal of plant pathology / European Foundation for Plant Pathology》2008,122(1):157-167
Among oomycetes, Plasmopara viticola on grape and Phytophthora infestans on potato are agronomically the most important pathogens requiring control measures to avoid crop losses. Several chemical
classes of fungicides are available with different properties in systemicity, specificity, duration of activity and risk of
resistance. The major site-specific fungicides are the Quinone outside inhibitors (QoIs; e.g. azoxystrobin), phenylamides
(e.g. mefenoxam), carboxylic acid amides (CAAs; e.g. dimethomorph, mandipropamid) and cyano-acetamide oximes (cymoxanil).
In addition, multi-site fungicides such as mancozeb, folpet, chlorothalonil and copper formulations are important for disease
control especially in mixtures or in alternation with site-specific fungicides. QoIs inhibit mitochondrial respiration, phenylamides
the polymerization of r-RNA, whereas the mode of action of the other two site-specific classes is unknown but not multi-site.
The use of site-specific fungicides has in many cases selected for resistant pathogen populations. QoIs are known to follow
maternal, largely monogenic inheritance of resistance; they bear a high resistance risk for many but not all oomycetes. For
phenylamides, inheritance of resistance is based on nuclear, probably monogenic mechanisms involving one or two semi-dominant
genes; resistance risk is high for all oomycetes. The molecular mechanism of resistance to QoIs is mostly based on the G143A
mutation in the cytochrome b gene; for phenylamides it is largely unknown. Resistance risk for CAA fungicides is considered
as low to moderate depending on the pathogen species. Resistance to CAAs is controlled by two nuclear, recessive genes; the
molecular mechanism is unknown. For QoIs and CAAs, resistance in field populations of P. viticola may gradually decline when applications are stopped. 相似文献
5.
薏米多酚细胞抗氧化及HepG2细胞毒性和抗增殖作用 总被引：2，自引：0，他引：2
【目的】了解薏米多酚的体内抗氧化能力,着重分析薏米结合多酚的抗氧化能力,确定结合多酚对总抗氧化能力的贡献;研究薏米多酚对肝癌细胞的毒性和抗增殖作用,在细胞层面上对薏米多酚的功能作用进行评价分析。【方法】以贵州黑谷薏米、辽宁5号薏米、龙薏1号薏米为原料,通过对薏米样品多酚类物质游离型和结合型部分构建细胞模型,评价细胞内抗氧化能力指数,以HepG2细胞为研究对象,测定分析薏米多酚提取物对细胞毒性的中位浓度CC50值和细胞抗增殖作用的半最大效应浓度EC50值。【结果】薏米结合型多酚抗氧化能力显著高于游离型多酚。不同品种间总多酚含量和抗氧化能力差异显著,辽宁5号薏米和龙薏1号薏米明显优于贵州黑谷薏米。对于HepG2细胞,薏米品种对于人体肝癌细胞具有明显的增殖抑制作用,且基本在试验浓度范围内,薏米样品本身无细胞毒性的存在。【结论】薏米作为中国传统的药食两用全谷物食品,含有丰富的多酚类物质,具有较强的抗氧化能力,之前的研究,往往仅考虑薏米游离型多酚,实际薏米中还存在大量结合型多酚。考虑到此结合型多酚,薏米多酚的抗氧化能力明显提升,且薏米多酚对肿瘤细胞具有较明显的抗增殖作用。 相似文献
6.
对１日龄感染ＣＡＡ雏鸡接种Ｌａｓｏｔａ弱毒疫苗后，其血清、泪液、胆汁中ＨＩ抗体滴度的变化进行了研究。结果发现，感染ＣＡＡ雏鸡Ｌａｓｏｔａ疫苗免疫后，三种体液中ＨＩ抗体滴度明显低于未感染ＣＡＡ的照雏鸡。 相似文献
7.
对１日龄雏鸡感染鸡贫血因子（ＣＡＡ）后血浆的凝血酶时间，凝血酶原时间，部分凝血活酶时间，纤维蛋白原含量及副凝试验等指标进行了检测。结果表明，感染ＣＡＡ雏鸡血浆凝血时间和部分凝血活酶时间分别于感染后７－２８日和１４－２１日明显延长；凝血酶原时间和纤维蛋白原含量于７－１４日虽吴现延长或减少，但无统计学意义；副凝试验于感染后７－１４日呈阳性反应。 相似文献
8.
S. S. Zhu X. L. Liu Y. Wang † X. H. Wu P. F. Liu J. Q. Li S. K. Yuan N. G. Si 《Plant pathology》2007,56(6):967-975
Plastic-house experiments were conducted over a 2-year period (2004–05) to estimate the effects of successive applications of flumorph or a mixture of flumorph with mancozeb to cucumber plants on selection for flumorph resistance in the downy mildew oomycete, Pseudoperonospora cubensis . Application of flumorph alone favoured the selection of resistant isolates of Ps. cubensis . Resistant populations were detected at a frequency of 2·5% after six successive applications of flumorph alone in a plastic house in 2004. Resistant isolates were also detected (4·8%) after eight successive applications of the mixture of flumorph and mancozeb in 2004, although the mixture gave significantly better disease control than flumorph alone and produced a slight delay in the development of resistance. In a second cucumber crop in the same plastic houses in 2004, the frequency of resistant isolates increased to 100% after three successive applications of flumorph or four of flumorph + mancozeb. Under laboratory conditions, most flumorph-resistant isolates showed high levels of resistance and their levels of pathogenicity and sporulation were as high as that of wild-type isolates. Flumorph showed cross-resistance with dimethomorph and iprovalicarb, but not with azoxystrobin, cyazofamid, cymoxanil or metalaxyl. These studies suggest a high risk for the occurrence of resistance to flumorph in Ps. cubensis in cucumber crops under plastic-house conditions. 相似文献
9.
【目的】建立米糠中酚类物质的大孔树脂分离纯化工艺,比较米糠提取物纯化前后总酚、总黄酮含量及抗氧化能力,为米糠的深加工利用提供参考。【方法】比较9种不同类型大孔吸附树脂(HPD-100、HPD-200A、HPD-300、HPD-700、D101、HPD-722、AB-8、ADS17和HPD-826)对米糠提取物中总酚的静态吸附和解吸性能,筛选出对脱脂米糠酚类物质纯化效果最佳的大孔吸附树脂类型;通过考察其静态吸附动力学曲线,比较不同上样液浓度、上样流速和上样体积下的动态吸附曲线以及采用不同浓度乙醇洗脱的解吸效果,建立米糠多酚的大孔吸附树脂吸附和解吸工艺条件;比较HPD-300型大孔吸附树脂纯化前后总酚、总黄酮含量,采用高效液相色谱法结合应用酚类标准品分析米糠提取物经大孔吸附树脂纯化前后其各单体酚类物质种类与含量,并通过氧自由基吸收能力(oxygen radical absorption capacity,ORAC)和细胞抗氧化分析法(cellular antioxidant activity,CAA)比较其纯化前后的抗氧化活性。【结果】9种类型大孔吸附树脂对脱脂米糠提取物酚类物质均有一定的吸附能力,其中HPD-300型大孔吸附树脂对脱脂米糠总酚静态吸附和解吸效果明显优于其他类型树脂,其饱和吸附量为9.04 mg GAE·g~(-1),解吸率为82.62%,同时米糠总酚静态吸附在6 h时达到饱和值。HPD-300型大孔吸附树脂最佳吸附和解吸工艺条件为:米糠酚类提取液上样浓度为1.0 mg GAE·m L-1,上样流速为3.0 BV·h~(-1),上样体积为3.5 BV,洗脱剂为70%乙醇溶液,洗脱流速为3.0 BV·h~(-1)。经HPD-300型大孔吸附树脂纯化后,米糠酚类提取物的总酚和总黄酮含量分别从纯化前的88.07μg GAE·mg~(-1)和30.04μg CE·mg~(-1)提高到320.72μg GAE·mg~(-1)和133.67μg CE·mg~(-1),分别提高了2.6和3.4倍。经高效液相色谱分析,米糠酚类提取物经HPD-300型大孔吸附树脂纯化后,其中的没食子酸、原儿茶酸、香草酸、对羟基苯甲酸、咖啡酸、丁香酸、表儿茶素、香草醛、对香豆酸和阿魏酸等10种酚类单体组成未见明显变化和损失,且上述酚类单体在提取物中的含量较纯化前分别提高0.4—2.4倍。纯化后提取物的ORAC和CAA值分别为3 248.21μmol TE·g~(-1)和95.24μmol QE·g~(-1),较纯化前的1 327.51μmol TE·g~(-1)和29.19μmol QE·g~(-1),分别提高了1.4和2.2倍。【结论】HPD-300型大孔吸附树脂适合米糠酚类物质的分离纯化,经其纯化后的米糠提取物中总酚、总黄酮含量及抗氧化活性提高1—3倍,且不会造成单体酚的明显损失。 相似文献
10.
羧酸酰胺类(CAAs)杀菌剂研究进展 总被引：5，自引：3，他引：2
羧酸酰胺类(Carboxylic acid amides, CAAs) 化合物是一类对卵菌病害具有优异防治效果的新型杀菌剂。该类杀菌剂由3组化学结构各不相同的化合物组成,包括肉桂酰胺、缬氨酰胺氨基甲酸酯和扁桃酰胺类。由于这3类杀菌剂具有相似的杀菌活性且相互间存在正交互抗药性,国际杀菌剂抗药性行动委员会已于2005年底将这3类具有不同化学结构的杀菌剂归为羧酸酰胺类杀菌剂。对CAA类杀菌剂的化学结构特征、生物学活性、作用机制与抗药性的最新研究进展进行了综述。 相似文献