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1.
The host suitability of five zucchini and three cucumber genotypes to Meloidogyne incognita (MiPM26) and M. javanica (Mj05) was determined in pot experiments in a greenhouse. The number of egg masses (EM) did not differ among the genotypes of zucchini or cucumber, but the eggs/plant and reproduction factor (Rf) did slightly. M. incognita MiPM26 showed lower EM, eggs/plant, and Rf than M. javanica Mj05. Examination of the zucchini galls for nematode postinfection development revealed unsuitable conditions for M. incognita MiPM26 as only 22% of the females produced EM compared to 95% of the M. javanica females. As far as cucumber was concerned, 86% of the M. incognita and 99% of the M. javanica females produced EM, respectively. In a second type of experiments, several populations of M. arenaria, M. incognita, and M. javanica were tested on zucchini cv. Amalthee and cucumber cv. Dasher II to assess the parasitic variation among species and populations of Meloidogyne. A greater parasitic variation was observed in zucchini than cucumber. Zucchini responded as a poor host for M. incognita MiPM26, MiAL09, and MiAL48, but as a good host for MiAL10 and MiAL15. Intraspecific variation was not observed among the M. javanica or M. arenaria populations. Cucumber was a good host for all the tested populations. Overall, both cucurbits were suitable hosts for Meloidogyne but zucchini was a poorer host than the cucumber.  相似文献   
2.
《Geobios》2014,47(5):315-324
A new genus and species of male cones of coniferophyte from the Lower Permian (Artinskian and Kungurian) deposits of the Urals, Russia is described: Uralostrobus voltzioides Naugolnykh nov. gen., nov. sp. The cone shows characters typical of some representatives of conifers belonging to the order Voltziales: more or less isometrical bracts of rhombic shape, prolonged sporangia with attenuate apices, and bisaccate pollen of Illinites-type. General information on the associated female seed scales and vegetative leafy shoots is given as well.  相似文献   
3.
For the initiation of embryogenic cucumber ( Cucumis sativus L.) cell lines, from excised radicles, directly in liquid medium, the culture regime, explant density and type and concentration of hormones were adjusted so that pro-embryogenic masses (PEMs) were formed within about 8 weeks. The established cucumber cell lines were maintained tor several years without loss of embryogenic and genetic stability. The ploidy level of somatic embryos from different cucumber eell lines was either diploid or tetraploid and depended on the ploidy level of Ihe cell line. Cucumber cell lines that produced only diploid embryos were obtained by selecting completely diploid explant material and growing it in the dark during the initiation phase. Mixoploid explains could lead to tetraploid or mixoploid ceil lines. Isolation and additional selection and subculturing of single PEMs resulted in either completely diploid or tetraploid cell lines, indicating that all cells of individual PEMs are either diploid or tetraploid. The ernbryogenic cucumber cell Imes, differing only in ploidy level, were indistinguishable in growth rate and embryogetiic potential and were genetically stable over several years.  相似文献   
4.
5.
By integrating next‐generation sequencing (NGS), bioinformatics, electron microscopy and conventional molecular biology tools, a new virus infecting kiwifruit vines has been identified and characterized. Being associated with double‐membrane‐bound bodies in infected tissues and having a genome composed of RNA segments, each one containing a single open reading frame in negative polarity, this virus shows the typical features of members of the genus Emaravirus. Five genomic RNA segments were identified. Additional molecular signatures in the viral RNAs and in the proteins they encode, together with data from phylogenetic analyses, support the proposal of creating a new species in the genus Emaravirus to classify the novel virus, which is tentatively named Actinidia chlorotic ringspot‐associated virus (AcCRaV). Bioassays showed that AcCRaV is mechanically transmissible to Nicotiana benthamiana plants which, in turn, may develop chlorotic spots and ringspots. Field surveys disclosed the presence of AcCRaV in four different species of kiwifruit vines in five different provinces of central and western China, and support the association of the novel virus with symptoms of leaf chlorotic ringspots in Actinidia. Data on the molecular features of small RNAs of 21–24 nucleotides, derived from AcCRaV RNAs targeted by host RNA silencing mechanisms, are also reported, and possible molecular pathways involved in their biogenesis are discussed.  相似文献   
6.
本文记述厉螨科一新属,邓厉螨属Tengilaelapsgen.nov,其主要特征;角化较强,体毛壮,背毛29对;颚角粗钝,具纵裂;头盖尖角形;胸板六角形,各角均尖突;殖腹板毛1对;各足股、膝节上均具长毛、模式种为天牛邓厉螨,新种Tengilaelapscerambyciussp.nov。另一新种为副单阳厉螨AndrolaelapsParasingularissp.nov。模式标本均采自云南省的甲虫体上。  相似文献   
7.
We present a simple and rapid technique for the double staining of plant peroxidase and other proteins in the same polyacrylamide gel using the principle of iodide oxidation followed by Coomassie Blue counterstain. The colored bands of peroxidase isozymes and proteins are easily distinguishable. An additional benefit of the method is the use of the low cost chemicals, as well as it eliminates the need for a potentially hazardous reagents frequently used in the detection of peroxidase isozymes. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
8.
Northern blot analysis revealed that a single 4.2 kb phytochrome mRNA species was detectable in cotyledons excised from five-day-old etiolated cucumber seedlings. Intact etiolated five-day-old cucumber seedlings were given a red light or benzyladenine treatment, and cotyledons were harvested at various times following treatment. The abundance of phytochrome mRNA in the cotyledons was quantitated using 32P-labeled RNA probes and slot blot analysis. By 2 h after irradiation the phytochrome mRNA level was reduced to 40% of the initial abundance and reaccumulation began by 3 h after irradiation. Reaccumulation of phytochrome mRNA to the time-zero dark control level was achieved by 10 h after treatment. A decrease in phytochrome mRNA abundance was evident by 2 h after benzyladenine treatment, and a maximal reduction to 45% of the time-zero dark control was attained by 4 h after treatment. No recovery of the phytochrome mRNA level was evident by 8 h after benzyladenine treatment. The abundance of actin mRNA was unaffected by benzyladenine treatment.  相似文献   
9.
Benzyladenine-induced changes in the translatable mRNA population in excised cucumber cotyledons were studied. Poly (A)+ RNA was prepared from etiolated cotyledons incubated with or without benzyladenine (BA) for various periods in the dark. Using nonequilibrium pH gradient electrophoresis-SDS polyacrylamide gel electrophoresis and isoelectric focusing-SDS polyacrylamide gel electrophoresis, both basic and neutral proteins translated in vitro were separated. About 240 spots were detected and 16 of them changed within 6 h after BA application. Some spots changed quickly (within 1–2 h). Among them, three were repressed markedly  相似文献   
10.
植物开花机理是生物学中的一个基本问题,多年来人们进行过许多的研究,积累了大量的事实,然而对开花的机理仍然还不甚清楚。因而在利用原有实验系统的同时,有必要寻找更多简单,又便于分析的实验系统。Jullien等报告离体培养的大豆子叶节能直接产生花芽。我们在建立离体培养黄瓜子叶直接单独形成雄花或雌花的实验系统的过程中,发现黄瓜幼苗去除顶芽后在子叶节处也能直接形成花芽。这一现象有可能用于深入研究各营养器官和花启动间关系等问题,定将  相似文献   
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