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Genetic diversity and mixed infections of begomoviruses infecting tomato, pepper and cucurbit crops in Nicaragua 总被引:1,自引:0,他引:1
M. Ala-Poikela E. Svensson ‡ A. Rojas T. Horko L. Paulin J. P. T. Valkonen A. Kvarnheden † 《Plant pathology》2005,54(4):448-459
Begomoviruses were detected in Nicaraguan fields of tomato ( Lycopersicon esculentum ) and adjacently growing plants of pepper ( Capsicum annuum ), chilli pepper ( C . baccatum ), cushaw ( Cucurbita argyrosperma ) and Mexican fireplant ( Euphorbia heterophylla ) using polymerase chain reaction (PCR) and universal begomovirus primers. All tomato and Mexican fireplant plants showing symptoms were infected with begomoviruses, while only 30–46% of the pepper, chilli pepper and cushaw plants showing symptoms tested virus-positive. No begomoviruses were found in potato. The virus species were provisionally identified by sequencing 533 bp of the viral coat protein gene ( AV1 ). Tomato severe leaf curl virus (ToSLCV), Tomato leaf curl Sinaloa virus (ToLCSinV) and Pepper golden mosaic virus (PepGMV) were found to infect both tomato and pepper. A new provisional species designated Tomato leaf curl Las Playitas virus (ToLCLPV) was detected in a tomato plant. Squash yellow mottle virus (SYMoV) and PepGMV were found in cucurbits, the latter for the first time in this host. Euphorbia mosaic virus (EuMV) was detected in Mexican fireplant. Sequencing of a larger number of PCR-amplified clones from selected plants revealed intraspecific viral sequence variability, and also multiple begomovirus infections which could represent up to three species in a single tomato or cushaw plant. Phylogenetic grouping of virus sequences did not correlate with the host of origin. 相似文献
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地锦草总黄酮的体外抑菌试验 总被引:7,自引:0,他引:7
采用醇提法从地锦草中提取其主要有效成分黄酮类化合物,通过滤纸片法对3种浓度(0.4、0.8、1.6mg/ml)的地锦草黄酮提取液进行抑菌实验。结果表明,地锦草黄酮提取液对巴氏杆菌、沙门氏菌的体外抑菌作用较强,1.6mg/ml的黄酮提取液对巴氏杆菌、沙门氏菌的抑菌直径分别达到(22.0±1.0)mm、(26.0±2.0)mm,随着黄酮浓度的增加,其抑菌作用也增强。地锦草黄酮对巴氏杆菌、沙门氏菌的MIC分别为0.625mg/ml、1.25mg/ml,地锦草黄酮提取液对金黄色葡萄球菌、大肠杆菌、链球菌也有一定的抑菌作用。 相似文献
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The interrelationships of seed yield components in Euphorbia lathyris L. have been studied by means of path-coefficient analysis. Two of seven components, ‘Number of flowers of primary inflorescence’ and ‘Number of flowers of secondary inflorescences’ proved to be of major importance through direct effects on ‘Total number of fruits’ as indicator of seed yield. Indirect effects generally arc being canalized via the same variables. Selection for seed yield is made possible through the relation between ‘Number of secondary branches’ and ‘Number of flowers of secondary inflorescences’. 相似文献
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刺梅嫩枝扦插育苗技术 总被引:2,自引:0,他引:2
使用全日照24h自动化间歇喷雾设备,采用半木质化刺梅嫩枝作插穗带叶扦插生根育苗的方法,具有生根速度快、育苗周期短、一年可生产多批及插穗来源丰富等优点,苗木成活率达97%。 相似文献
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以矮生一品红的幼叶、幼茎、茎芽为外植体,研究了影响丛芽诱导、增殖、生根壮苗的组培快繁的主要因素.结果表明:茎段、茎芽是诱导丛芽的较好试材.适合诱导胚性愈伤组织和芽分化的培养基为MS+6-BA1.0mg/L+NAA0.1mg/L;适合丛芽增殖成苗的培养基为MS+6-BA1.0mg/L+IAA0.1mg/L,继代增殖培养40d的平均增殖倍数为11;适合生根壮苗的培养基为1/2MS+IBA0.9mg/L,开始生根天数为8d。生根率可达85%.采用河砂和营养土两步炼苗。移栽成活率可达90%以上. 相似文献