Search results for "Quercus"

Preliminary observations on fungal endophytic community and mycorrhizal status in symptomless Quercus ilex seedlings

2014

Recently, a study on the Quercus ilex L. decay caused by biotic and abiotic agents has hypothesized alterations on endophytic and mycorrhizal fungal populations. Since holm oak is among the most representative Mediterranean species, that occurs widely in both urban and rural areas, in this work we preliminarly report these symbiotic fungal communities in asymptomatic seedlings, in order to compare these populations with those found in seedlings subjected to water and saline stress. Endophytic fungi were isolated from twigs and leaves and identified by morphological and molecular analysis. The ectomycorrhizal status was evaluated on root samples randomly selected to calculate the percentage …

Cork Taint of Wines: Role of the Filamentous Fungi Isolated from Cork in the Formation of 2,4,6-Trichloroanisole by O Methylation of 2,4,6-Trichlorop…

2002

ABSTRACT Cork taint is a musty or moldy off-odor in wine mainly caused by 2,4,6-trichloroanisole (2,4,6-TCA). We examined the role of 14 fungal strains isolated from cork samples in the production of 2,4,6-TCA by O methylation of 2,4,6-trichlorophenol (2,4,6-TCP). The fungal strains isolated belong to the genera Penicillium (four isolates); Trichoderma (two isolates); and Acremonium , Chrysonilia , Cladosporium , Fusarium , Mortierella , Mucor , Paecilomyces , and Verticillium (one isolate each). Eleven of these strains could produce 2,4,6-TCA when they were grown directly on cork in the presence of 2,4,6-TCP. The highest levels of bioconversion were carried out by the Trichoderma and Fusar…

Genetic diversity in Sicilian populations of Quercus ilex (Fagaceae)

2013

Raimondo, F. M., Scialabba, A., Guarino, R. & Spallino, R. E.: Genetic diversity in Sicilian populations of Quercus ilex (Fagaceae). — Fl. Medit. 23: 245-253. 2013. — ISSN: 1120-4052 printed, 2240-4538 online. Recent studies on the genetic structure of the Italian populations of Quercus ilex demonstrated their high diversity, particularly in the Sicilian metapopulation. In order to check if the holm oak stands in the mountains of NW Sicily could have some relationship with Q. ilex subsp. ballota (distributed in Spain and NW Africa), 26 specimens from the Sicilian most distinctive Q. ilex populations have been compared with some representative populations of the Italian Peninsula, North Afri…

Downy-oak woods of Italy: phytogeographical remarks on a controversial taxonomic and ecologic issue

2014

The importance of downy oak as an integral component of the "submediterranean" woods has been underscored by many studies. Nevertheless, terms like "submediterranean" and "downy oak" are some of the most poorly understood concepts in European phytogeographic and taxonomic research. Downy oak is well known to be a problematic taxon. The name "Quercus pubescens" (= Q. humilis) combines populations characterized by increasing phenotypic and genomic polymorphisms along north-south gradients, which is explained as the result of a "founder effect" produced by a relatively fast post-glacial re-colonization of the northern areas through rare long-distance dispersal events. On the other hand, polymo…

Flora and vegetation of pastures utilized by the Sicilian Black Pig of the Nebrodi Mountains (NE Sicily).

2007

Rediscovery of Cerroneuroterus apenninus (Trotter, 1923) (Hymenoptera: Cynipidae: Cynipini) a valid species from Italy with description and neotype d…

2021

Neuroterus apenninus Trotter, 1923 associated with a Cerris section oak, Quercus cerris L., was rediscovered in Italy in 2017. Alessandro Trotter (1903) described a leaf gall collected on Q. cerris from the Italian Apennines; he did not obtain the gall inductor and ascribed the galls to the genus Neuroterus, based on morphological similarity with other Neuroterus galls. We have found the same gall and obtained the gall inducer. Detailed study of morphological characters of adults revealed that the species belongs to the genus Cerroneuroterus Melika & Pujade-Villar, 2010. The asexual generation of Cerroneuroterus apenninus comb. n. is described for the first time, a neotype is designated…

Changes in the protein profile of Quercus ilex leaves in response to drought stress and recovery

2009

To characterize the molecular response of holm oak to drought stress and its capacity to recover 9-month-old Quercus ilex seedlings were subjected to three treatments for a 14-d period: (i) continuous watering to field capacity (control plants, W), (ii) no irrigation (drought treatment, D), and (iii) no irrigation for 7d followed by a watering period of 7d (recovery treatment, R). In drought plants, leaf water potential decreased from -0.72 (day 0) to -0.99MPa (day 7), and -1.50MPa (day 14). Shoot relative water content decreased from 49.3% (day 0) to 47.7% (day 7) and 40.8% (day 14). Photosystem II quantum yield decreased from 0.80 (day 0) to 0.72 (day 7) and 0.73 (day 14). Plants subjecte…

Pointer years in tree-ring width and earlywood-vessel area time series of Quercus robur—Relation with climate factors near its northern distribution …

2013

Abstract For a long time, radial growth of pedunculate oak (Quercus robur) in relation to environmental factors has been studied in Central Europe. However, there is insufficient information on oak growth in the Baltic region. Climate–growth interactions have been mostly investigated by correlation/response analysis between ring width and climatic factors. Other wood anatomical proxies, and also pointer year analysis, which focuses on weather extremes, can be sources of additional information. Wood samples were taken from 40 sites across Latvia. Tree-ring width (TRW) and mean area of earlywood vessels (EVA) were measured. To assess differences in wood formation among sites, a PCA was perfor…

Phytopathogenic Bacteria Associated with Bacterioses of Common Oak (Quercus robur L.) in Ukraine

2022

Studying the biological characteristics of the causative agents of bacteriosis of the common oak (Quercus robur L.) (to highlight the links between the key factors of pathogenesis and bacterial groups) is a new and relevant area of research. This work aims to identify the species composition of phytopathogenic bacteria associated with common oak bacteriosis and to study the morphological, cultural, and biochemical properties of pathogens. To establish the general phytosanitary state of the surveyed stands, classical forest inventory and phytopathological (visual on based on typical symptoms of the disease and macroscopic) methods were used. The properties of isolated bacteria were studied u…

The role of forest fire severity on vegetation recovery after 18 years. Implications for forest management of Quercus suber L. in Iberian Peninsula

2016

Wildfires are a widespread phenomenon in Mediterranean environments. Wildfires result in different fire severities, and then in contrasting plant cover and floristic composition. This paper analyses the recovery of the vegetation eighteen years after a wildfire in Catalonia. The Pinus pinaster ssp. forest was affected by three different severities in July 1994, and studied the spring of 1995 and again in 2008. After eighteen years (2012), our research found that burnt sites constitute a dense forest with a broad variety of species, including many young pines, shrubs and herbaceous plants, but that the risk of fire remains very high, due to the large quantity of fuel and the flammability of …