نتایج جستجو برای: quercus spp
تعداد نتایج: 57431 فیلتر نتایج به سال:
The lack of desirable oak (Quercus spp.) regeneration on upland sites is a problem in the Central Hardwood Region. While reintroduction fire, thinning, and/or harvesting has been proposed as solution to increase regeneration, these treatments may have limited impact productive sites, and effects growth residual midstory stems not clear. This study examined response white alba) mature, oak-domin...
The main characteristics of the Quercus pollination season were studied in 14 different localities of the Iberian Peninsula from 1992-2004. Results show that Quercus flowering season has tended to start earlier in recent years, probably due to the increased temperatures in the pre-flowering period, detected at study sites over the second half of the 20th century. A Growing Degree Days forecasti...
In this study three species of the genus Quercus section Erythrobulanus (Quercus coccinea, Quercus rubra, Quercus uelurina) were investigated. All occur together as canopy trees in forests of southern New England. Acorns of each Quercus species were planted in plots located in five zones that represent a range of forest gap/canopy conditions that can occur within a southern New England forest. ...
The structure and function of Mediterranean mixed oak forests are seriously threatened by climate change the exotic pathogen Phytophthora cinnamomi. Both factors have been individually studied in some detail, but we a poor understanding their interactive effects on plant performance species coexistence. We conducted greenhouse experiment where seedlings three coexisting with contrasting suscept...
این مطالعه با هدف بررسی تغییرات تاج پوشش گیاهی در 4 مکان مرتعی در اطراف شهرستان سمیرم واقع در استان اصفهان و یک منطقه جنگلی در شهرستان لردگان از توابع استان چهار محال و بختیاری در دو دهه گذشته انجام شده است. برای این منظور تصاویر ماهواره لندست در 6 دوره زمانی سال های 1990، 1999، 2000، 2001، 2002 و 2009 و یک تصویر ماهواره irs-p6 (سنجنده awifs) مربوط به سال 2006 انتخاب و مورد پردازش قرار گرفت. اب...
این مطالعه به منظور شناسایی باکتری های پاتوژن موجود بر سطح سوند و بررسی توانایی آن ها در تشکیل بیوفیلم انجام گرفت. در این بررسی 50 نمونه سوند ادراری از بیماران مختلف بستری در بخش icu بیمارستان بررسی گردید. باکتری های جدا شده با استفاده از تست های بیوشیمیایی شناسایی و توانایی تشکیل بیوفیلم آن ها در حضور و عدم حضور بیوسایدهای بیسموت اتان دی تیول (bisedt) و بیسموت پروپان دی تیول (bispdt) و اسانس آ...
AIRBORNE ALLERGENIC POLLEN IN A NATURAL AREAS – HORNACHUELOS NATURAL PARk , CORDOBA , SOUTHERN SPAIN
The present study shows the results of monitoring the atmospheric pollen in the atmosphere of an area of natural vegetation, the Hornachuelos Natural Park, Cordoba, southern Spain, during a six years (1998-2003). Special attention was paid in the seasonal and intra-diurnal characteristics of airborne allergenic pollen. During this period, 31 pollen types were described, some of them rare in aer...
Oaks (Quercus spp.) are considered model plants for studying plant evolution and natural gene introgression. Beijing area is at the junction between Taihang Mountain Yanshan Mountain, it an overlapping distribution of several deciduous oaks native to China. Interspecific hybridization often occurs in sympatric sibling species, resulting blurred interspecific boundaries hindering development bre...
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