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81.
常瑾  赵敬钊 《蛛形学报》2000,9(2):116-121
应用 二次正交旋转组合设计方法,对稻田生态系统中3种捕食性天敌(三突花蛛Misumenops tricuspidata(Tabricius)、草间钻头蛛Hylyphantes graminicora(Sundevall)、真水狼蛛Pirata piraticus(Clerk)和1种害虫(白背飞虱Sogatella furcifera(Horvath)的共存系统进行研究,获得了天敌对害虫控制作用的数  相似文献   
82.
Xia CM  Chen J  Wang J  Fan MX  Xiao F  Cao YX  Li L  Shen LL  Zhu DN 《生理学报》2008,60(4):453-461
许多研究表明,延髓头端腹外侧区(rostral ventrolateml medulla,RVLM)的NO/NOS系统参与心血管活动的中枢调节.本实验以结扎Wistar大鼠左冠状动脉前降支法建立急性心肌缺血(acute myocardial ischemia,AMI)动物模型,观察针刺"内关"穴改善AMI大鼠的心功能作用,同时检测大鼠RVLM区神经元型一氧化氮合酶(neuronal nitric oxide synthase,nNOS)和诱导型一氧化氮合酶(inducible nitric oxide synthase,iNOS)表达的变化,进而探讨针刺治疗AMI的中枢机制.实验观察显示,AMI大鼠心功能各项指标减弱,伴随外周血去甲肾上腺素(norepinephrine,NE)和脑钠肽(brain natriuretic peptide,BNP)水平显著升高,同时RVLM区nNOS阳性神经元数和nNOS mRNA表达升高,而iNOS水平则降低.针刺"内关"穴(Pe 6)(每天30 min,连续5天)改善心功能,降低AMI大鼠血清中NE和BNP的水平,同时升高iNOS并降低nNOS在RVLM的表达.以上结果提示,针刺治疗心肌缺血的同时可以调节iNOS/NO和nNOS/NO在RVLM的变化,这可能与针刺通过调节RVLM区的NO含量进而降低交感传出,从而改善AMI大鼠的心功能有关.  相似文献   
83.
The aim of the present study was to understand the effects of abiotic conditions on seasonal feeding activity of diverse herbivores on the same oak tree species in two different forests. We tracked changes in herbivore feeding activities on an oak tree species (Quercus serrata) in two localities: a low elevation small hillock forest patch (Muan, MN) and a middle elevation mountain forest patch (Mt. Jirisan, JR). A total of five sites were selected in each of two forest localities. Data for leaf expansion, leaf chemical qualities, leaf damage ratio, and numbers of lepidopteran caterpillars were collected during spring (May) and summer (July to August), 2012. Leaf expansion rate was higher at the low hillock forest than the mid‐mountain forest from spring to summer. Nitrogen and carbon content decreased seasonally at both localities. Lepidopteran larval diversity was high in the mid‐mountain forest, and two‐way ANOVA showed that species richness of lepidopteran larvae was significantly affected by the interaction between season and locality. Leaf damage by all herbivores was higher in the low hillock forest than the mid‐mountain forest in spring, but was higher in the mid‐mountain forest in summer. Relative proportion of general herbivores increased from spring to summer in the mid‐mountain forest, but not in the low hillock forest. Canonical Correspondence Analysis (CCA) ordination showed that altitude‐ and season‐related variables were significant species and environment interaction factors. Our data indicate that locality and temperature disproportionally affected the feeding activities of diverse herbivores in two different temperate forests.  相似文献   
84.
Transient receptor potential canonical channel (TRPC) is a nonselective cation channel permeable to Ca2+, which express in many cell types, including neurons. However the alterations in TRPC receptor expressions in response to status epilepticus (SE) have not been explored. Therefore, the present study was designated to elucidate the roles of TRPC3 in neuronal death and vasogenic edema within the rat piriform cortex (PC) following SE. In non-SE animals, TRPC3 immunoreactivity was abundantly detected in the PC. Following SE, TRPC3 immunoreactivity was increased in neurons. Furthermore, TRPC3 expression was detected in endothelial cells that did not contain it in non-SE animals. Loss of SMI-71 (a blood–brain barrier antigen) immunoreactivity was also observed in TRPC3 positive endothelial cells. In addition, FJB positive neurons and vasogenic edema were noticeably detected in the PC. To directly determine whether TRPC3 activation is correlated to SE-induced vasogenic edema formation and neuronal damages in the PC, the effect of Pyr-3 (a TRPC3 antagonist) on SE-induced insults were investigated. Pyr-3 infusion effectively attenuated vasogenic edema in the PC as compared to the vehicle. Therefore, our findings indicate that TRPC3 activation/overexpression induced by SE may involve BBB disruption and neuronal damages in the rat PC following SE. Therefore, the present study was TRPC3 may play an important role in SE-induced vasogenic edema formation through BBB disruptions in the rat PC.  相似文献   
85.
The biochemical mechanisms underlying thidiazuron (TDZ)-induced regeneration in plant cells have not been clearly elucidated. Exposure of leaf explants of Echinacea purpurea to a medium containing TDZ results in undifferentiated cell proliferation and differentiated growth as mixed shoot organogenesis and somatic embryogenesis. The current studies were undertaken to determine the potential roles of auxin, indoleamines, and ion signaling in the dedifferentiation and redifferentiation of plant cells. E. purpurea leaf explants were found to contain auxin and the related indoleamine neurotransmitters, melatonin, and serotonin. The levels of these endogenous indoleamines were increased by exposure to TDZ associated with the induction of regeneration. The auxin-transport inhibitor 2,3,5-triiodobenzoic acid and auxin action inhibitor, p-chlorophenoxyisobutyric acid decreased the TDZ-induced regeneration but increased concentrations of endogenous serotonin and melatonin. As well, inhibitors of calcium and sodium transport significantly reduced TDZ-induced morphogenesis while increasing endogenous indoleamine content. These data indicate that TDZ-induced regeneration is the manifestation of a metabolic cascade that includes an initial signaling event, accumulation, and transport of endogenous plant signals such as auxin and melatonin, a system of secondary messengers, and a concurrent stress response.  相似文献   
86.

Background

Cotton fibers (produced by Gossypium species) are the premier natural fibers for textile production. The two tetraploid species, G. barbadense (Gb) and G. hirsutum (Gh), differ significantly in their fiber properties, the former having much longer, finer and stronger fibers that are highly prized. A better understanding of the genetics and underlying biological causes of these differences will aid further improvement of cotton quality through breeding and biotechnology. We evaluated an inter-specific Gh × Gb recombinant inbred line (RIL) population for fiber characteristics in 11 independent experiments under field and glasshouse conditions. Sites were located on 4 continents and 5 countries and some locations were analyzed over multiple years.

Results

The RIL population displayed a large variability for all major fiber traits. QTL analyses were performed on a per-site basis by composite interval mapping. Among the 651 putative QTLs (LOD > 2), 167 had a LOD exceeding permutation based thresholds. Coincidence in QTL location across data sets was assessed for the fiber trait categories strength, elongation, length, length uniformity, fineness/maturity, and color. A meta-analysis of more than a thousand putative QTLs was conducted with MetaQTL software to integrate QTL data from the RIL and 3 backcross populations (from the same parents) and to compare them with the literature. Although the global level of congruence across experiments and populations was generally moderate, the QTL clustering was possible for 30 trait x chromosome combinations (5 traits in 19 different chromosomes) where an effective co-localization of unidirectional (similar sign of additivity) QTLs from at least 5 different data sets was observed. Most consistent meta-clusters were identified for fiber color on chromosomes c6, c8 and c25, fineness on c15, and fiber length on c3.

Conclusions

Meta-analysis provided a reliable means of integrating phenotypic and genetic mapping data across multiple populations and environments for complex fiber traits. The consistent chromosomal regions contributing to fiber quality traits constitute good candidates for the further dissection of the genetic and genomic factors underlying important fiber characteristics, and for marker-assisted selection.  相似文献   
87.
黄河三角洲作为我国重要的后备土地资源区,土壤盐渍化问题突出,切实掌握季节性土壤水盐状况及其微域特征是该区土壤盐渍化防控和土地资源高效利用的重要基础。选择黄河三角洲垦利县,通过野外调查实测与室内化验分析获取土壤水盐含量数据,利用统计分析、GIS空间插值、实地观测与数据分析对比等方法,分析了研究区夏季土壤水盐状况及其微域变异规律。结果显示:研究区夏季土壤水盐含量总体较高,含盐量以中度盐渍化为主,随着土层深度的增加含盐量呈上升趋势,且各层土壤含盐量呈显著正相关性;含盐量较高的地区主要分布在该区东北部和中东部,含盐量较低的地区主要分布在西南部和中部;土壤含盐量从大到小的植被类型依次为光板地→碱蓬→高粱→芦苇→茅草→水稻→棉花→玉米;土壤盐分微域变化特征明显,含盐量受距路边远近、不同耕作措施、地形部位、植被群落等因素影响较大,表现出微域规律性和复杂性。该研究基本摸清了研究区夏季时相的土壤水盐状况及其微域特征,为黄河三角洲农作物栽培管理及土壤资源可持续利用提供了科学依据。  相似文献   
88.
摘要:【目的】结合纳米技术建立检测大肠杆菌(Escherichia coli)O157︰H7高灵敏检测技术。【方法】采用化学共沉淀法制备出核心粒径约为10 nm的免疫纳米磁颗粒,柠檬酸钠还原法制备粒径约为20 nm的免疫胶体金。压电免疫传感器通过金黄色葡萄球菌蛋白A(Protein A from Staphylococcus aureus SPA)法将抗体固定于石英晶振上,两种免疫纳米颗粒借助不同的抗体连接于传感器上对检测频率信号进行放大。【结果】SPA在石英晶振上的最佳固定浓度和时间为1.2 mg/mL和40 min,抗体的最佳固定浓度和时间为1.0 mg/mL和60 min。压电免疫传感器通过两种免疫纳米颗粒的放大作用,使其对大肠杆菌O157︰H7的检测限从104 cfu/mL提高到101 cfu/mL。【结论】免疫纳米颗粒强化对压电免疫传感器的检测频率信号具有很好的放大效应,可以明显提高其检测灵敏度。  相似文献   
89.
利用随机扩增多态性DNA技术对广东省2000年度稻瘟病菌群体的遗传结构进行了分析。以相似性系数为0.62阀值时,可将采集于广东省三大生态稻作区、早稻和晚稻生长季节的104个菌株划分为14个遗传宗谱;其中宗谱5和宗谱8的菌株数各占总数的25%,为优势宗谱;宗谱4和12的菌株数各占总数的14.4%和9.6%,为亚优势宗谱;其余的29个菌株,分别归属于其它10个宗谱,其中有5个宗谱是单菌株宗谱。本年度稻瘟病菌群体的遗传结构呈现明显的区域性特性:遗传结构呈由北向南多样化的趋势;各个稻作区甚或亚区有其特异性的宗谱。本年度稻瘟病菌群体的遗传结构也显示分明的生长季节特性:来源于早稻和晚稻生长季节的菌株完全分属于宗谱图的上下两个半区,彼此之间不存在共同的宗谱;而且后者的遗传宗谱要比前者的复杂、多样。研究还表明,虽然稻瘟病菌群体的遗传结构2000年度与1998-1999年度的比较存在较大的差异,但是两者仍然具有良好的相承性和可比性。如何进一步验证和把握稻瘟病菌群体的遗传结构所表现出的时空特性是值得我们进一步探讨的重要课题。  相似文献   
90.
甜荞是异花授粉作物,自然界中的甜荞种质资源多存在生物学混杂现象。每份甜荞种质资源可以分化出若干份新的遗传资源类型,其遗传背景复杂。简化甜荞种质资源的遗传背景,准确描述新品种的亲子代关系和遗传背景一直是世界荞麦工作者面对的技术难题。甜荞种质资源的繁育需要采取隔离措施,实施过程中需要考虑甜荞花粉粒大小、甜荞授粉机制、访问昆虫种类以及种子量多少等。为解决上述问题,本研究建立了以隔离杂交圃、隔离单繁圃、隔离扩繁圃、隔离比较圃和田间试验圃的荞麦繁育新方法——"五圃法",以期开发出不同类型的新的荞麦资源,在育种中可针对性的配制强优势组合,为新品种选育提供种质材料。  相似文献   
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