排序方式： 共有13条查询结果，搜索用时 46 毫秒
1.
S. Diamandis 《Forest Pathology》1987,17(6):348-355
Two Euramerican poplar clones, ‘I-214’and ‘I-45/51′, were badly damaged by frost cracks in 1981 and 1985. Thermocouples attached to 12 trees showed that clone ‘I-45/51’was more resistant to winter and late frosts, possibly due to its significantly thicker and rougher bark in comparison to ‘I-214′. 相似文献
2.
S. Diamandis 《Forest Pathology》1979,9(2):78-88
The height increment pattern of healthy and diseased Norway spruce over the period 1961–75 was studied to test the association of some climatic factors with height increment reduction and eventually foliar browning. Air temperature during December-March inclusive, high velocity wind (22->34 knots) duration during December-March incl. and rainfall during May-August incl. over the same period 1961–75 were examined. It was shown that the last outbreak of “top-dying” in Scotland started in 1971. A correlation analysis and a stepwise multiple regression analysis were conducted to find possible relationships between annual height increments and climate. Results suggested that the coincidence of extreme values of the three considered climatic factors during the period 1971–75 may be responsible for the sharp decline of height increments in 1971 and severe outbreak of the disease. 相似文献
3.
Establishment and dissemination of hypovirulent strains of Cryphonectria parasitica in Greece 
下载免费PDF全文
下载免费PDF全文 S. Diamandis C. Perlerou G.T. Tziros V. Christopoulos E. Topalidou 《Forest Pathology》2015,45(5):408-414
Chestnut blight caused by Cryphonectria parasitica has been one of the major reasons for the decline of chestnut cultivation in Greece over the last 50 years. A previous detailed study of the vc types of the fungus has revealed only four vc types in the entire country, those of EU‐1, EU‐2 and EU‐10 with the dominant being EU‐12 counting for 88% of the isolates. As the loss in orchard trees reached in some chestnut producing prefectures over 35% of the trees, the decision was taken to apply biological control on a nationwide scale. The project was implemented in 17 prefectures during the period 2007–2009. Hypovirulent (hv) strains of C. parasitica which were infected by the CHV‐1 subtype I (Italian subtype) viruses which occur naturally in Greece were used. The necessary hypovirulent inoculum was prepared at the Forest Research Institute during the period 2007–2009 on a large scale, however, with laboratory care. Three million inoculations were made around accessible developing cankers over three consecutive years by trained personnel. An extensive evaluation conducted in 2011 in the 12 of the 17 treated prefectures, where no natural hypovirulence had been found before, demonstrated not only the successful establishment of hypovirulence but also profound dissemination and healing of non‐inoculated cankers. The extent of dissemination varied significantly among sampling plots and among prefectures. The conclusion is drawn that CHV‐1 subtype I has successfully established and spread into chestnut orchards and coppice forests resulting in a gradual decline of chestnut blight. 相似文献
4.
A.?M.?Vettraino O.?Morel C.?Perlerou C.?Robin S.?Diamandis A.?VanniniEmail author 《European journal of plant pathology / European Foundation for Plant Pathology》2005,111(2):169-180
The Phytophthora complex associated with Castanea sativa Mill. was investigated in five European countries in 35 regions and with respect to various domestication levels. Annual precipitation and length of drought season were the main parameters that regulated the presence of Phytophthora species in the chestnut stands. Seven species of Phytophthora were detected; three of these, P. megasperma, P. cryptogea and P. syringae had not been previously reported on sweet chestnut. P. cinnamomi. P. cambivora and P. citricola were most frequently isolated. P. cinnamomi and P. cambivora were the species significantly associated with declining trees with symptoms of Ink Disease. P. cinnamomirequired distinct ecological conditions compared to the other species. P. cinnamomi was never detected in sites characterized by minimum temperatures below 1.4 °C, maximum temperature above 28 °C, or soil pH below 5.4. The results obtained provide useful information for modeling the probability of Ink Disease, crown decline and associated Phytophthora species in chestnut groves in global climatic change scenarios. 相似文献
5.
Forces for morphogenesis investigated with laser microsurgery and quantitative modeling 总被引：1，自引：0，他引：1
Hutson MS Tokutake Y Chang MS Bloor JW Venakides S Kiehart DP Edwards GS 《Science (New York, N.Y.)》2003,300(5616):145-149
We investigated the forces that connect the genetic program of development to morphogenesis in Drosophila. We focused on dorsal closure, a powerful model system for development and wound healing. We found that the bulk of progress toward closure is driven by contractility in supracellular "purse strings" and in the amnioserosa, whereas adhesion-mediated zipping coordinates the forces produced by the purse strings and is essential only for the end stages. We applied quantitative modeling to show that these forces, generated in distinct cells, are coordinated in space and synchronized in time. Modeling of wild-type and mutant phenotypes is predictive; although closure in myospheroid mutants ultimately fails when the cell sheets rip themselves apart, our analysis indicates that beta(PS) integrin has an earlier, important role in zipping. 相似文献
6.
为改善车辆不同作业环境下的操控性能,防止地域及季节气温差异导致转向系动态响应偏离其设计初衷,该文以非独立悬架车辆为例,对考虑温度效应的车辆摆振系统动力学行为进行了分析。基于热弹性力学考察了温度效应对转动副间隙的影响,建立了计入温度效应的转向传动机构含间隙车辆摆振系统动力学模型。通过数值算例分析了某1030货车摆振响应的分岔特性和初值特性,讨论了车速、温度等参数对摆振系统全局动力学行为的影响,研究表明,温度的改变在85～110km/h车速区间内会导致转向轮摆角周期运动形态的改变,且这种影响在高车速区段下比中低车速区段更为明显,而当车速为100km/h、温度为-40℃时左转向轮摆角中值为负,意味着有向右跑偏趋势;50℃时摆角中值由负变正,说明有改为向左跑偏的趋势。研究结果可为全天候车辆防摆振设计提供参考。 相似文献
7.
Conidia of Leptographium wageneri var. ponderosum, Leptographium wageneri var. pseudotsugae and Leptographium wageneri var. wageneri germinated on wounded roots of ponderosa pine (Pinus ponderosa), Douglas fir (Pseudotsuga menziesii), and pinyon (Pinus edulis), but not on unwounded roots. On wounds, germination occurred regardless of the combination of pathogen variety and plant species. When wounded roots of ponderosa pine and Douglas fir seedlings were inoculated with conidia of L. w. var. ponderosum and L. w. var. pseudotsugae, respectively, 87-100% of the seedlings became infected. When unwounded roots were inoculated with wooden blocks colonized with L. wageneri, 60-66% of the seedlings became infected. The development of L. w. var. ponderosum and L. w. var. pseudotsugae on agar was compared with their development on agar overlaid with either cellophane or Nucleopore membranes. Undulating hyphae were found commonly in and on the agar, but less frequently on the membranes. On both membranes, mycelia formed mats which were tightly appressed to the surface; mats were not formed on the agar. On both agar and the membranes, two or more hyphae often formed a strand. When L. w. var. ponderosum mycelia were allowed to colonize the surface of an unwounded pine root, strands, undulating hyphae and poorly formed mats were seen. 相似文献
8.
Castanea sativa, one of the most precious forest trees in Greece, is affected by the spread of chestnut blight all over the country. Identification and mapping of the vegetative compatibility (vc) types of the fungus Cryphonectria parasitica was carried out and the occurrence of hypovirulence was checked. In 11 chestnut populations distributed all over Greece, 627 isolates were obtained and their vc type was determined. Four vc types were identified by means of tester isolates: EU‐12 was found to be the dominant vc type reaching a percentage of 88%, with EU‐2 (6%), EU‐10 (3%) and EU‐1 (2%) following. EU‐12 was found in all 11 populations investigated whereas EU‐2 was isolated from five populations and EU‐10 and EU‐1 were found only in one population each. Natural hypovirulence was also found in five populations of 11 examined. Perithecia were not found in either population, a finding supported by the fact that all Greek isolates examined belonged to a single mating type, MAT‐1. The low diversity in vc types, the absence of the perithecial stage and the occurrence of natural hypovirulence in some areas support the feasibility of successful application of biological control on the national level in Greece. 相似文献
9.
The first distribution map of Seiridium (Coryneum) cardinale (Wag.) Sutton and Gibson which causes the cypress canker in Greece is given. A recent survey all over the country has shown that S. W. Greece and the Ionian islands are already under heavy attack whereas in central and N. Greece and the island of Krete only restricted spots have been found. Strict sanitation measures are imposed to prevent building up and diffusion of the disease. 相似文献
10.
Current status of the Dutch elm disease pathogen populations affecting Ulmus minor in Greece 下载免费PDF全文
下载免费PDF全文 One hundred and eight Ophiostoma ulmi sensu lato isolates were collected from field elm trees with symptoms in 14 Prefectures of Greece. The purpose of this study was to assign Greek isolates to species and afterwards subspecies of the DED fungi and to analyse the genetic variability within the Greek populations of these pathogens. Isolates were compared with six reference strains belonging to O. ulmi and the two subspecies of O. novo‐ulmi. The structure of the population has been analysed by means of morpho‐physiological features (growth rates, colony morphology and fertility responses) and by DNA sequencing and PCR‐RFLP amplification of the cerato‐ulmin (cu) and the colony type (col1) gene regions. According to fertility tests, both subspecies of O. novo‐ulmi were detected in Greece, but none of the isolates collected was identified as O. ulmi. O. novo‐ulmi ssp. novo‐ulmi occurred more frequently than ssp. americana (73 and 35 isolates, respectively) and their ranges overlapped. All isolates that behaved as ssp. novo‐ulmi in the fertility tests had the cu, as well as the col1 profile of ssp. novo‐ulmi. Surprisingly, all isolates that behaved as O. novo‐ulmi ssp. americana in the fertility test had the cu, as well as the col1 (with one exception) profile of O. novo‐ulmi ssp. novo‐ulmi. A possible explanation for this inconsistency could be the occurrence of hybridization between the two subspecies in Greece. 相似文献