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排序方式: 共有120条查询结果,搜索用时 15 毫秒
1.
Oded Cohen Ozgur Batuman Yoni Moskowits Alexander Rozov Elisha Gootwine Munir Mawassi Moshe Bar-Joseph 《Phytoparasitica》2005,33(2):141-148
Mechanical inoculations with contaminating tools and propagation of infected budwood were considered the main causes for the
omnipresence of multiple viroid species among citrus and other Middle Eastern and Mediterranean fruit trees and grapevines.
However, neither means could explain viroid infections of wild trees — scattered on terrains inaccessible to humans — nor
the finding of similar viroids among graft-incompatible plants. Northern hybridization of RNA extracts made of scrapings from
the surfaces of goat (Capra hircus) horns that were rubbed against etrog (Citrus medica) stems infected with a citrus viroids complex, revealed accumulation of considerable amounts ofCitrus exocortis viroids (CEVd) andHop stunt viroids (HSVd). Experimental transmission of both CEVd and HSVd was obtained by rubbing healthy citrus plants with goat horns that
had been rubbed 24 h earlier on infected etrog stems. These results implicate goats as possible vectors of viroids. Transmissionvia goats could have facilitated the long-range spread of viroids among cultivated and wild plants andvice versa and also among graft-incompatible plants. 相似文献
2.
As a result of rapid land development in Israel during the past three decades, some 26 species of higher plants, about one percent of the local flora, have become extinct. In addition to listing such species, this paper deals with the ecological implications of this finding. Recommendations for the prevention of further damage to the local flora, and rare plants in particular, are given. 相似文献
3.
Yuval Ramot Michal Steiner Netanel Amouyal Yossi Lavie Guy Klaiman Abraham J. Domb Abraham Nyska Tal Hagigit 《Journal of toxicologic pathology》2021,34(1):11
Fracture-related infections remain a leading cause of morbidity and mortality. We aimed to establish a simple contaminated radial osteotomy model to assess the efficacy of a biodegradable polymer poly(sebacic-co-ricinoleic acid) [p(SA-RA)] containing 20% w/w gentamicin. A unilateral transverse osteotomy was induced in Sprague-Dawley (SD) rats, followed by application of Staphylococcus aureus suspension over the fracture. After successfully establishing the contaminated open fracture model, we treated the rats either systemically (intraperitoneal cefuroxime), locally with p(SA-RA) containing gentamicin, or both. Control groups included non-contaminated group and contaminated groups that were either untreated or treated with the polymer alone. After 4 weeks, the bones were subjected to micro-CT scanning and microbiological and histopathology evaluations. Micro-CT analysis revealed similar changes in the group subjected to both local and systemic treatment as in the non-contaminated control group. Lack of detectable bacterial growth was noted in most animals of the group subjected to both local and systemic treatment, and all samples were negative for S. aureus. Histopathological evaluation revealed that all treatment modalities containing antibiotics were highly effective in reducing infection and promoting callus repair, resulting in early bone healing. While p(SA-RA) containing gentamicin treatment showed better results than cefuroxime, the combination of local and systemic treatment displayed the highest therapeutic potential in this model. 相似文献
4.
Summary Achenes of wild forms of Anemone coronaria growing in Israel differ in their germination requirements from achenes of the cultivated de Caen type. The optimum temperature for dark germination was between 10–15°C in the former and between 15–20°C in the latter. Maximum daily rates of germination were higher, reaching 16% per day, and the minimum lag period between sowing and seedling emergence was shorter in achenes of the cultivated than in those of the wild anemone when the two types were incubated under identical conditions. Wild achenes showed a marked post-harvest maturation requirement, and attained full germination, a minimum pre-emergence lag period after sowing, and a maximum daily germination rate only when dry-stored for several months subsequent to harvesting. In the cultivated plant this requirement was far less pronounced or absent. Most embryos in freshly harvested achenes of both the wild and the cultivated anemone were torpedo-shaped but in the cultivated form embryos were larger. In both types embryos remained unchanged in shape and size during dry storage. 相似文献
5.
An artificial capillary barrier to improve root zone conditions for horticultural crops: physical effects on water content 总被引:1,自引:1,他引:0
Eviatar Ityel Naftali Lazarovitch Moshe Silberbush Alon Ben-Gal 《Irrigation Science》2011,29(2):171-180
Capillary barriers (CBs) occur at the interface of two soil layers having distinct differences in textural and hydraulic characteristics.
The objective of this study was to introduce an artificial CB, created by a layer of gravel below the root zone substrate,
in order to optimize conditions for the cultivation of horticultural crops. Potential root zone formats were analyzed with
and without the gravel CBs for variables including the following: depth of CB; barrier separating the root zone from the surrounding
soil; and root zone soil texture. Field and simulated results revealed that artificial CBs increased root zone water content
and changed water flow dynamics. Volumetric soil water content was increased by 20–70%, depending on the soil texture and
depth of the barrier. Sandy soil texture and shallower placement resulted in relatively higher water content. For sandy soil
without plants, a shallow (0.2 m depth) CB increased water content of the overlaying soil by 50% compared to the control.
The introduction of a gravel CB below the root zone of pepper plants (Capsicum Annum L.) lead to 34% higher matric head, 50% lower diurnal fluctuations in matric head and 40% increase in pepper fruit yield.
Increasing water content by way of artificial CBs appeared to improve the water use efficiency of pepper plants. Such an improvement
could lead to reduced water and fertilizer application rates and subsequent reduction in contamination below the root zone.
This is especially relevant for substrates of low water-holding capacity typically used in horticulture crop production. 相似文献
6.
Human-made contour banks are a central component of theShikim water harvesting system in Israels Negev Desert.Efficient water capture depends on the presence of a stable microphytic crustwhich directs surplus surface runoff into the banks where it is stored. We usedsimulated rainfall to examine the impact of soil surface disturbance on runoffand sediment transport, and the effect of this on the efficiency of resourcecapture within the Shikim system. Two disturbance regimes:1) removal of the microphytic crust only, and 2) removal of the crust and shrubpatches by cultivation, were compared with an undisturbed control. In theundisturbed state, 32% of rainfall was redistributed as runoff. This runoffpenetrated approximately 27% deeper under the shrub patches compared with themicrophytic crust. When the microphytic crust was destroyed by simulatedtrampling, the runoff coefficient declined to 13%, and there was no significantdifference in water penetration between shrub and crust patches. Completedestruction of the shrub hummocks and crust by cultivation resulted in adeclinein the runoff coefficient to 6%. The result of sustained disturbance in thesepatchy Negev shrublands is a breakdown in spatial heterogeneity, a loss ofecosystem function, a reduction in ecosystem goods and services such as plantdiversity and production, and ultimately a reduction in pastoral productivity.These results reinforce the view that microphytic crusts are critical for theefficient operation of the Shikim water harvesting system.Given that practices such as cultivation and trampling which disturbmicrophyticcrusts result in enhanced infiltration, crusts should be left intact tomaximisethe water harvesting efficiency in these desert landscapes.This revised version was published online in May 2005 with corrections to the Cover Date. 相似文献
7.
Lev-Yadun S Ne'eman G Abbo S Flaishman MA 《Science (New York, N.Y.)》2006,314(5806):1683; author reply 1683
Kislev et al. (Reports, 2 June 2006, p. 1372) described Neolithic parthenocarpic fig fruits and proposed that they derive from trees propagated only by cuttings and thus represent the first domesticated plant of the Neolithic Revolution. Because parthenocarpic fig trees naturally produce both seeded and seedless fruits and are capable of spontaneous reproduction, we argue that the finds do not necessarily indicate cultivation, nor horticulture predating grain crops. 相似文献
8.
Shpyrko OG Streitel R Balagurusamy VS Grigoriev AY Deutsch M Ocko BM Meron M Lin B Pershan PS 《Science (New York, N.Y.)》2006,313(5783):77-80
X-ray measurements reveal a crystalline monolayer at the surface of the eutectic liquid Au82Si18, at temperatures above the alloy's melting point. Surface-induced atomic layering, the hallmark of liquid metals, is also found below the crystalline monolayer. The layering depth, however, is threefold greater than that of all liquid metals studied to date. The crystallinity of the surface monolayer is notable, considering that AuSi does not form stable bulk crystalline phases at any concentration and temperature and that no crystalline surface phase has been detected thus far in any pure liquid metal or nondilute alloy. These results are discussed in relation to recently suggested models of amorphous alloys. 相似文献
9.
10.
Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is an explosive compound whose extensive use has resulted in significant contamination of soils and groundwater worldwide. We studied its in situ biodegradation along the unsaturated zone beneath an explosives wastewater lagoon using compound-specific isotope analysis (CSIA) of RDX in the unsaturated zone, together with biodegradation slurry experiments under anaerobic conditions. We found the highest degradation potential of RDX and its nitroso derivatives in the upper part of the soil profile while in the lower parts, RDX-degradation potential was lower and the nitroso derivatives tended to persist. This was also observed in the field, as reflected by the isotopic composition of RDX along the profile. We also found a correlation between biodegradation potential and clay content: biodegradation was further enhanced in layers characterized by high-clay content or in those influenced by the high-clay layers. In addition, in the presence of high organic matter content, further enhancement of biodegradation was observed. We obtained different isotopic enrichment factors (?) for RDX biodegradation in different sections of the unsaturated profile and suggest that different degradation pathways exist simultaneously in situ, in variable proportions. Using the range of enrichment factors, we were able to assess the biodegradation extent of RDX at different sampling points along the profile, which ranged between 30 and 99.4%. The novel application of CSIA together with slurry experiments provides better insight into degradation processes that are otherwise difficult to detect and assess. 相似文献