نتایج جستجو برای: oak leaf

تعداد نتایج: 94114  

Journal: :The New phytologist 2016
Gonzalo Pérez-de-Lis Sergio Rossi Rosa Ana Vázquez-Ruiz Vicente Rozas Ignacio García-González

This study addresses relationships between leaf phenology, xylogenesis, and functional xylem anatomy in two ring-porous oak species, the temperate Quercus robur and the sub-Mediterranean Q. pyrenaica. Earlywood vessel (EV) formation and leaf phenology were monitored in 2012 and 2013. Ten individuals per species were sampled at each of three sites located in NW Iberian Peninsula. EV areas measur...

2015
Adam Kimak Zoltan Kern Markus Leuenberger

Foliar samples were harvested from two oaks, a beech, and a yew at the same site in order to trace the development of the leaves over an entire vegetation season. Cellulose yield and stable isotopic compositions (δ(13)C, δ(18)O, and δD) were analyzed on leaf cellulose. All parameters unequivocally define a juvenile and a mature period in the foliar expansion of each species. The accompanying sh...

2016
József Vuts Christine M Woodcock Mary E Sumner John C Caulfield Katy Reed Daegan JG Inward Simon R Leather John A Pickett Michael A Birkett Sandra Denman

BACKGROUND Agrilus bigutattus (Fabricius) is a forest pest of increasing importance in the United Kingdom. The larvae damage weakened native oaks and are thought to contribute to premature tree death. Suspected links with acute oak decline (AOD) are not yet confirmed, but AOD-predisposed trees appear to become more susceptible to A. biguttatus attack. Thus, management may be necessary for contr...

2005
Marc D. Abrams

Before European settlement, vast areas of the eastern US deciduous forest were dominated by oak species. Evidence indicates that periodic understory fire was an important ecological factor in the historical development of oak forests. During European settlement of the late 19th and early 20th century, much of the eastern United States was impacted by land-clearing, extensive timber harvesting, ...

Journal: :Chemosphere 2016
Chris Geron Ryan Daly Peter Harley Rei Rasmussen Roger Seco Alex Guenther Thomas Karl Lianhong Gu

Leaf-level isoprene and monoterpene emissions were collected and analyzed from five of the most abundant oak (Quercus) species in Central Missouri's Ozarks Region in 2012 during PINOT NOIR (Particle Investigations at a Northern Ozarks Tower - NOx, Oxidants, Isoprene Research). June measurements, prior to the onset of severe drought, showed isoprene emission rates and leaf temperature responses ...

2013
Carlos Calderón Guerrero Madeleine S. Günthardt-Goerg Pierre Vollenweider

BACKGROUND Despite abatement programs of precursors implemented in many industrialized countries, ozone remains the principal air pollutant throughout the northern hemisphere with background concentrations increasing as a consequence of economic development in former or still emerging countries and present climate change. Some of the highest ozone concentrations are measured in regions with a M...

Journal: :Tree physiology 2008
Francisco José Juárez-López Alfonso Escudero Sonia Mediavilla

A quantitative analysis was applied to the stomatal and biochemical limitations to light-saturated net photosynthesis under optimal field conditions in mature trees and seedlings of the co-occurring evergreen oak, Quercus ilex L., and the deciduous oak, Q. faginea Lam. Stomatal limitation to photosynthesis, maximal Rubisco activity and electron transport rate were determined from assimilation v...

Journal: :Phytopathology 2005
Jennifer M Davidson Allison C Wickland Heather A Patterson Kristen R Falk David M Rizzo

ABSTRACT During 2001 to 2003, the transmission biology of Phytophthora ramorum, the causal agent of sudden oak death, was studied in mixedevergreen forest, a common forest type in northern, coastal California. Investigation of the sources of spore production focused on coast live oak (Quercus agrifolia) and bay laurel (Umbellularia californica), dominant hosts that comprised 39.7 and 46.2% of t...

2017
Jose A. Ramírez-Valiente Alyson Center Jed P. Sparks Kimberlee L. Sparks Julie R. Etterson Timothy Longwell George Pilz Jeannine Cavender-Bares

Widely distributed species are normally subjected to spatial heterogeneity in environmental conditions. In sessile organisms like plants, adaptive evolution and phenotypic plasticity of key functional traits are the main mechanisms through which species can respond to environmental heterogeneity and climate change. While extended research has been carried out in temperate species in this regard...

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