Plants of one evergreen oak (Quercus ilex) and three deciduous oaks (Q. faginea, with small leaves; Q. pyrenaica and Q. robur, with large leaves) were exposed both to filtered air and to enhanced ozone levels in Open-Top Chambers. Q. faginea and Q. pyrenaica were studied for the first time. Based on visible injury, gas exchange, chlorophyll content and biomass responses, Q. pyrenaica was the mo...

the oak genus (quercus l.) is one of the most important genera of beach family (fagaceae) that has ecological and economical importance. chestnutleaf oak (quercus castaneifolia c.a. mey.) is native to iran and distributed in hyrcanian forests. pure and mixed stands of this taxon have covered about 6.5 % of hyrcanian forests. this study was undertaken to evaluate the effects of ecological factor...

In summer 1992, isoprene emission was measured on intact leaves and branches of Quercus alba (L.) at two heights in a forest canopy. Isoprene emission capacity (measured at 30 degrees C and a photosynthetic photon flux density of 1000 micro mol m(-2) s(-1)) was significantly higher in sun leaves than in shade leaves when expressed on a leaf area basis (51 versus 31 nmol m(-2) s(-1); P < 0.01). ...

The enzyme, ß-glucogallin: 1,2,3,6-tetra-O-galloyl-ß-D-glucose 4-O-galloyltransferase, which catalyzes the last common step in the biosynthesis of the two subclasses of hydrolyz­ able tannins, i.e. gallotannins and ellagitannins, was purified 868-fold from leaves of peduncu­ late oak ( Quercus robur, syn. Q. pedunculata) to apparent homogeneity. Polyclonal antibod­ ies against this pivotal enzy...

We n&asured leaf respiration in 18 eastern deciduous forest tree species to determine if there were differences in tempera i m-respiration response functions among species or among c opy positions. Leaf respiration rates were measured in situ an4 on detached branches fordcerpensylvanicum L., A. rubrum i., Betula spp. (B. alleghaniensis Britt. and B. renta L.), Caryq glabra (Mill.) Sweet, Cornus...

The preferred livelihood assets for meat and nutritious milk in thousands villages of Kurdistan rejoin/Iraq are sheep goats. They generally rely on free roaming rangeland during the growing seasons. In order to maintain their livestock scarcity forages at winter seasons, leaves twigs (Quercus aegilops, Q. infectoria libani) harvested dried as (dry leaf faggots) autumn season use major substitut...

Decomposition of three leaf species (Alnus glutinosa, Eucalyptus globulus and Quercus robur) were examined in a headstream. During two months decomposing leaves were periodically analysed for nutrient content, soluble sugars, phenols, protein precipitation capacity, total fiber, weight loss, microbial and macroinvertebrate colonisation. The leaves of the three species showed similar patterns in...

Freshwater ecosystems are positioned at low levels in the landscape and receive large inputs of diverse plant-based detritus, a major source of energy for consumers in aquatic ecosystems. We conducted Þeld experiments in Urbana, IL to determine the independent and combined effects of leaves of common tree species including thenorthern redoak (Quercus rubraL.), sugarmaple (Acer saccharumMarshall...

Quercus cerris is an important oak species extended in large areas of Eastern Europe and Minor Asia that has a thick bark which is not utilized at all. The sorption performance of cork from Quercus cerris bark with four polycyclic aromatic hydrocarbons (PAHs) (acenaphthene, fluorene, phenanthrene, and anthracene) was investigated. Quercus cerris cork was characterized for elemental analysis, ac...

Isoprene is synthesized and emitted in large amounts by a number of plant species, especially oak (Quercus sp.) and aspen (Populus sp.) trees. It has been suggested that isoprene improves thermotolerance by helping photosynthesis cope with high temperature. However, the evidence for the thermotolerance hypothesis is indirect and one of three methods used to support this hypothesis has recently ...