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101.
Laura Righetti Roberta Paris Claudio Ratti Matteo Calassanzio Chiara Onofri Davide Calzolari Wulf Menzel Dennis Knierim Gianmaria Magagnini Daniela Pacifico Gianpaolo Grassi 《European journal of plant pathology / European Foundation for Plant Pathology》2018,150(3):575-588
Interveinal chlorosis and leaf margin wrinkling are widespread symptoms of Cannabis sativa. They are traditionally attributed to the so-called hemp streak virus (HSV), but its existence has not been demonstrated yet. To our knowledge, no molecular investigation has so far been performed in order to identify the causal agent of this symptomatology, we therefore decided to use traditional and molecular virology techniques to better characterize symptoms and pursue the etiological agent. No pathogenic virus was found by using targeted PCR reactions and by RNA sequencing, whereas we were able to detect the Cannabis cryptic virus (CanCV) with both techniques. We, therefore, developed an RT-qPCR assay based on a CanCV-specific TaqMan probe and applied it to a wide range of symptomatic and symptomless plants, using a two-step (for quantification), or a one-step (for fast detection) protocol. Both symptoms and the virus were only shown to be transmitted vertically and did not pass via mechanical inoculation or grafting, though we could not find any cause-effect correlation between them. In fact, the virus was found in all the tested hemp samples, and its abundance varied greatly between different accessions and individuals, independently from the presence and severity of symptoms. The suggestion that hemp streak is caused by a virus is therefore questioned. Some abiotic stresses seem to play a role in triggering the symptoms but this aspect needs further investigation. For breeding purposes, a selection of parental plants based on the absence of symptoms proved to be efficient in containment of the disease. 相似文献
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Dissolved and colloidal phosphorus fluxes in forest ecosystems—an almost blind spot in ecosystem research
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Roland Bol Dorit Julich Dominik Brödlin Jan Siemens Klaus Kaiser Michaela Anna Dippold Sandra Spielvogel Thomas Zilla Daniela Mewes Friedhelm von Blanckenburg Heike Puhlmann Stefan Holzmann Markus Weiler Wulf Amelung Friederike Lang Yakov Kuzyakov Karl‐Heinz Feger Nina Gottselig Erwin Klumpp Anna Missong Carola Winkelmann David Uhlig Jakob Sohrt Klaus von Wilpert Bei Wu Frank Hagedorn 《植物养料与土壤学杂志》2016,179(4):425-438
Understanding and quantification of phosphorus (P) fluxes are key requirements for predictions of future forest ecosystems changes as well as for transferring lessons learned from natural ecosystems to croplands and plantations. This review summarizes and evaluates the recent knowledge on mechanisms, magnitude, and relevance by which dissolved and colloidal inorganic and organic P forms can be translocated within or exported from forest ecosystems. Attention is paid to hydrological pathways of P losses at the soil profile and landscape scales, and the subsequent influence of P on aquatic ecosystems. New (unpublished) data from the German Priority Program 1685 “Ecosystem Nutrition: Forest Strategies for limited Phosphorus Resources” were added to provide up‐to‐date flux‐based information. Nitrogen (N) additions increase the release of water‐transportable P forms. Most P found in percolates and pore waters belongs to the so‐called dissolved organic P (DOP) fractions, rich in orthophosphate‐monoesters and also containing some orthophosphate‐diesters. Total solution P concentrations range from ca. 1 to 400 µg P L?1, with large variations among forest stands. Recent sophisticated analyses revealed that large portions of the DOP in forest stream water can comprise natural nanoparticles and fine colloids which under extreme conditions may account for 40–100% of the P losses. Their translocation within preferential flow passes may be rapid, mediated by storm events. The potential total P loss through leaching into subsoils and with streams was found to be less than 50 mg P m?2 a?1, suggesting effects on ecosystems at centennial to millennium scale. All current data are based on selected snapshots only. Quantitative measurements of P fluxes in temperate forest systems are nearly absent in the literature, probably due to main research focus on the C and N cycles. Therefore, we lack complete ecosystem‐based assessments of dissolved and colloidal P fluxes within and from temperate forest systems. 相似文献
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Daniela Moyankova Aneta Lyubenova Slavtcho Slavov Dimitar Djilianov 《European journal of plant pathology / European Foundation for Plant Pathology》2014,138(1):149-155
The Phytophthora pathogens are among the most important pests in the modern agriculture and forestry. This makes them a subject of intensive studies, including laboratory experiments with in vitro culture on various plant-derived media. Here we show that leaf extracts from the resurrection endemic plant Haberlea rhodopensis stimulates significantly the in vitro growth of various isolates from several Phytophthora species. The extracts stimulate the formation of oospores in some heterothallic species. In this respect, the idea to propose Haberlea extracts as a potential ingredient of culture media for Phytophthora spp. maintenance under controlled conditions or as a component of detection systems for Phytophthora presence in nature seems quite attractive and promising. 相似文献
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三种南方典型水稻土长期试验下有机碳积累机制研究Ⅲ.两种水稻土颗粒有机质结构特征的变化 总被引:4,自引:1,他引:3
采用固体交叉极化魔角自旋13C核磁共振(CPMAS13C-NMR)波谱技术对长期不同施肥处理下红壤性水稻土和太湖地区黄泥土本体土壤以及水稳性团聚体中颗粒有机质(POM)的化学结构特征进行了研究。结果表明,不同施肥处理下本体土壤和不同粒径水稳性团聚体中POM的结构组成相似,主要由烷氧C、烷基C和芳香C组成,其中以烷氧C含量最高。施肥改变了本体土壤POM中各类C原子的相对百分含量,有机肥以及化肥配施有机肥条件下烷氧C含量明显降低,芳香C和酚基C含量有不同程度的增加,表明POM的稳定性增强;单施化肥下烷氧C含量最高,而烷基C、芳香C和芳香度均最低,POM的稳定性减弱,不利于POM的积累。施肥改变了黄泥土不同粒径水稳性团聚体中POM各类C原子的相对百分含量,从而使得不同粒径中POM对其团聚体的稳定性作用发生变化;而红壤性水稻土不同粒径水稳性团聚体POM各类C原子的相对百分含量并未明显受到施肥措施的影响。 相似文献
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Daniela Simon Dorina Schoenrock Ingo Nolte Wolfgang Baumgrtner Ronnie Barron Reinhard Mischke 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2009,38(4):521-528
Background: Mammary tumors are the most common neoplasms in female dogs. Malignant tumors may carry a poor prognosis and necessitate surgery. Few data are available on the value of cytologic examination as a diagnostic or prognostic tool for mammary tumors in dogs. Objectives: The objectives of this study were to determine whether cytologic findings in fine‐needle aspirate specimens of canine mammary tumors correlate with histopathologic results and whether the cytologic diagnosis is associated with postoperative outcome. Methods: In this prospective study, fine‐needle aspirate samples were obtained from 50 mammary tumors in 50 dogs. Results of cytologic and histopathologic examination were compared, using the histologic diagnosis as the reference method. Kaplan–Meier log rank analysis was used to evaluate univariate association of the cytologic diagnosis with duration of survival, local control, and metastasis‐free interval. Results: Adequate cytologic samples were obtained in 43/50 (86%) cases. The cytologic diagnosis correlated with the histologic diagnosis for benign and malignant tumors in 40/43 (93%) and 35/43 (81%) cases, respectively. Cytologic examination had a sensitivity of 88% and a specificity of 96% for the diagnosis of malignancy. The cytologic diagnosis had significant univariate association with duration of survival (P=.016), recurrence‐free interval (P=.003), and metastasis‐free interval (P=.014). Conclusions: Cytologic examination of mammary tumors in the dog has satisfactory accuracy, sensitivity, and specificity for the diagnosis of malignancy and is associated with postoperative outcome. Further studies on the diagnostic accuracy of cytology as well as multivariate analysis of its preoperative prognostic value in mammary tumors in the dog are warranted. 相似文献
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Matias Bermann Daniela Lourenco Vivian Breen Rachel Hawken Fernando Brito Lopes Ignacy Misztal 《Journal of animal science》2021,99(4)
The introduction of animals from a different environment or population is a common practice in commercial livestock populations. In this study, we modeled the inclusion of a group of external birds into a local broiler chicken population for the purpose of genomic evaluations. The pedigree was composed of 242,413 birds and genotypes were available for 107,216 birds. A five-trait model that included one growth, two yield, and two efficiency traits was used for the analyses. The strategies to model the introduction of external birds were to include a fixed effect representing the origin of parents and to use unknown parent groups (UPG) or metafounders (MF). Genomic estimated breeding values (GEBV) were obtained with single-step GBLUP using the Algorithm for Proven and Young. Bias, dispersion, and accuracy of GEBV for the validation birds, that is, from the most recent generation, were computed. The bias and dispersion were estimated with the linear regression (LR) method,whereas accuracy was estimated by the LR method and predictive ability. When fixed UPG were fit without estimated inbreeding, the model did not converge. In contrast, models with fixed UPG and estimated inbreeding or random UPG converged and resulted in similar GEBV. The inclusion of an extra fixed effect in the model made the GEBV unbiased and reduced the inflation. Genomic predictions with MF were slightly biased and inflated due to the unbalanced number of observations assigned to each metafounder. When combining local and external populations, the greatest accuracy can be obtained by adding an extra fixed effect to account for the origin of parents plus UPG with estimated inbreeding or random UPG. To estimate the accuracy, the LR method is more consistent among scenarios, whereas the predictive ability greatly depends on the model specification. 相似文献