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1.
菟丝子(Cuscuta spp.)是一种寄生植物,利用菟丝子为介体可以将植物病毒或类菌原体(mycoplasma like organism)从一株植物传染到另一株植物上。杨一朗陈景耀分别用大豆菟丝子和南方菟丝子为媒介成功地将甘薯丛枝病从甘薯传到长春花上,产生花器叶化、侧枝丛生病状。 相似文献
2.
A virus, serologically related to isolates of cherry leaf rollvirus (CLRV) from Prunus avium (L.) L. and Sambucus nigra L.was transmitted to a range of herbaceous plants from leavesor roots of thirty-one of forty-seven trees of Betula spp. growingat two heathland sites in Berkshire. Ageing leaves of virus-infectedindividuals which had mild chiorotic blotches or ring and linepatterns in July showed bright yellow ring and line patternsin October. In the season after B. verrucosa seedlings wereinoculated with CLRV isolates, leaves developed chlorotic ringand blotch patterns; the symptoms being similar whether theinocula were originally isolated from S. nigra, P. avium orB. verrucosa. Palisade and mesophyll cells of naturally infectedleaves of B. verrucosa contained chloroplasts in which granalorganization was appreciably less distinct than that of chloroplastsfrom virus-free leaves. In many instances, virus-infected leafcells had spherical virus-like particles about 30 mn in diametercontained within tubular structures in cell wall projections;these structures were not seen in virus-free material. An isolate of CLRV from B. verrucosa, purified from systemicallyinfected leaves of Nicotiana clevelandii Gray by ammonium sulphateprecipitation and differential centrifugation, contained twomajor components having sedimentation coefficients of 118s and130s. Each component was composed of spherical particles withdiameters in the range 26–30 nm and having buoyant densitiesin caesium chloride of 1·460 and 1·493 gm/cm3.Polyacrylamide gel electrophoresis of preparations from bothbuoyant components indicated that they each contained a singlespecies of protein whose molecular weight was in the range 53,000–54,000daltons. 相似文献
3.
以感染类菌原体ＭＬＯ的泡桐组培苗为病原繁殖材料，采用差速离心和Ｐｅｒｃｏｌｌ不连续密度梯度离心来提纯ＭＬＯ作为免疫抗原制备兔抗血清。抗血清经健康汁液吸收后，作为第一抗体，用异硫代氰酸荧光素ＦＩＦＣ标记的羊抗兔免疫球蛋白作为第二抗体，进行间接免疫荧光显微镜检查染病组织中的ＭＬＯ特异性荧光。经与ＤＡＰＩ染色技术比较，找出了适宜的徒手切片和减少非特异性反应的途径。此技术具有灵敏度高、特异性强和测定简便等特点。适用于ＭＬＯ组织定位、组培苗脱毒效果评估、病原株系鉴定和病害检疫等。 相似文献
4.
The effects of some insecticides on Nephotettix virescens (Distant), a leafhopper vector of virus and MLO diseases, were studied with particular reference to their efficacy in affecting vector behaviour and transmission of rice tungro virus (RTV). When 10- and 15-day old seedlings from carbofuran-treated seeds were exposed to viruliferous vectors in cages, the percentages of transmission were 40 and 50, respectively against cent per cent in the control. Spraying of EC formulations of dimethoate, phosphamidon and methamidophos was not effective but decemethrin showed spectacular knockdown effect and gave absolute protection against RTV transmission upto 7 days. Since the transmission threshold of RTV is considerably shorter than of mycoplasmal diseases, the treatments affecting RTV transmission may reasonably be expected to be quite effective against MLO diseases like rice yellow dwarf and sandal spike, transmitted by N. virescens. 相似文献
7.
Pressler cores were taken of Quercus petraea and Q. robur treesfrom young German provenance stands and mature mixed plantationsin England. The concentration of total phenolics extracted fromthe outer heartwood was measured and significant differencesfound between the two species. Concentrations of oak lactones,measured from provenance samples, also varied significantlybetween the species. However, the difference in total phenolicsbetween species was much lower among the trees from the mixedplantations than from the provenance trials. Q. petraea wascharacterized by lower levels of total phenolics but greaterconcentrations of oak lactones than Q. robur. A comparison betweenlate and early flushing Q. petraea trees found no significantdifference in total phenolics between these phenological types. 相似文献
8.
Captan was found to have an inhibitory effect on the seedlinggrowth of Picea sitchensis, Pinus sylvestris, and Tsuga heterophylla.A single application of captan reduced the rate of shoot growthfor at least two weeks, with a further decrease after a secondtreatment. Seedlings grown in sand appeared to be more adverselyaffected than those grown in soil. Weights of root, shoot, andleaves were all reduced in treated plants grown in sand. Nophytotoxic effects were detected when captan was applied totomato, barley, or cress seedlings grown in either sand or soil. It is suggested that the use of captan should be avoided duringgrowth analysis experiments on conifer seedlings, or, if fungalproblems make its use desirable, experimentation should be delayedfor at least three weeks after treatment. 相似文献
9.
Cherry Leaf Roll Virus in Juglans regia in the United Kingdom 总被引：1，自引：0，他引：1
Cherry leaf roll virus (CLRV) was detected in foliage, pollenor seeds of 43 of 113 mature/overmature Juglans regia L.; twohad foliar yellow-brown ring patterns whereas seven other infectedtrees had leaf necroses. Male catkins of a few infected treeswere malformed and blackened. Infection was rare (3/43) in the widely scattered J. regia ofnorthern England and Scotland, but commoner (40/70) in southernEngland. When J. regia seed was grown in methylbromide treated soil,six per cent (18/300) of the seedlings were symptomlessly infected.Four out of ten groups of imported seedlings were infected toa similar extent, CLRV being present in a total of 40 out of1146 trees aged five years or less. When 3 years old, CLRV infectedJ. regia were shorter and thinner than healthy seedlings. CLRV from walnut was serologically distinguishable from Betula,Prunus, Cornus and Sambucus isolates. One English walnut isolate(Ox) was distinguishable from two Italian walnut isolates. Anisolate (Sr) of CLRV obtained in Finland from Sambucus racemosaL. was antigenically distinct from S. ebulus and S. nigra isolates. 相似文献
10.
介绍枣树脱除MLO的理论依据,茎尖组织培养和热处理后茎尖培养2种常见脱除MLO的组织培养技术,阐述症状观察法、电子显微镜法、荧光染色等几种枣树脱毒苗检测方法的特点. 相似文献