نتایج جستجو برای: plant canopy

تعداد نتایج: 405039  

Importance of probability distribution functions in natural resource studies is increasing due to their effective roles in better understanding of vegetation structure and providing conceptual models of quantitative indices of plant species. The present study was performed to model the distribution of height and canopy area of Cionura erecta L. shrub, using probability distribution functions in...

The aim of the study was to determine the most important environmental factors (topography, climate, and soil) affecting changes in production and canopy cover of plant variations and to prepare prediction maps, based on the most important factor, in semi-steppe rangelands of Hir-Baghrou, Ardabil province, Iran. First, by detecting the vegetation types and different classes of environmental fac...

2009
ANNE K. ESCHTRUTH JOHN J. BATTLES

The current rate of invasive species introductions is unprecedented, and the dramatic impacts of exotic invasive plants on community and ecosystem properties have been well documented. Despite the pressing management implications, the mechanisms that control exotic plant invasion remain poorly understood. Several factors, such as disturbance, propagule pressure, species diversity, and herbivory...

Journal: :Plant, cell & environment 2002
J. S. Sperry U. G. Hacke R. Oren J. P. Comstock

Many aspects of plant water use -- particularly in response to soil drought -- may have as their basis the alteration of hydraulic conductance from soil to canopy. The regulation of plant water potential (Psi) by stomatal control and leaf area adjustment may be necessary to maximize water uptake on the one hand, while avoiding loss of hydraulic contact with the soil water on the other. Modellin...

2001
THOMAS W. SAPPINGTON SHOIL M. GREENBERG ROBERT A. TISDALE

The beet armyworm, Spodoptera exigua (Hübner), is a sporadic but devastating secondary pest of cotton. Scouting cotton for egg masses is commonly recommended for identifying potential outbreaks and forproper timingof insecticide applications.However, there is disagreement regarding where to look on the plant for beet armyworm eggs. We investigated and quantiÞed placement of egg masses by labora...

2013
Pedro Antonio Tíscar Juan Carlos Linares

Tree recruitment is a key process underlying stand dynamics and sustainability in managed forests. Woody plant cover is known to affect the regeneration success of Pinus nigra, suggesting the existence of facilitative plant-plant interactions. The regeneration patterns of this Mediterranean pine were analyzed across its distribution area, using data from 3226 plots of the Spanish National Fores...

Journal: :Tree physiology 2014
Roland Pieruschka Hendrik Albrecht Onno Muller Joseph A Berry Denis Klimov Zbigniew S Kolber Zbyněk Malenovský Uwe Rascher

The photosynthesis of various species or even a single plant varies dramatically in time and space, creating great spatial heterogeneity within a plant canopy. Continuous and spatially explicit monitoring is, therefore, required to assess the dynamic response of plant photosynthesis to the changing environment. This is a very challenging task when using the existing portable field instrumentati...

Journal: :محیط شناسی 0
رضا تمرتاش مربی دانشگاه علوم کشاورزی و منابع طبیعی ساری محمدرضا طاطیان استادیار دانشگاه علوم کشاورزی و منابع طبیعی ساری مائده یوسفیان دانشجوی کارشناسی ارشد مرتع داری، دانشگاه آزاد اسلامی واحد نور

carbon sequestration in soil and plant biomass is the most simple and economic way for co2 decrease that is important in environment improvement. this research was done in miankaleh region of behshahr in mazandaran for comparison of carbon sequestration in different plant types. firstly, plant types were determined and dominant species was identified in each type. number and size of plots was o...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2006
Elsa E Cleland Nona R Chiariello Scott R Loarie Harold A Mooney Christopher B Field

Shifting plant phenology (i.e., timing of flowering and other developmental events) in recent decades establishes that species and ecosystems are already responding to global environmental change. Earlier flowering and an extended period of active plant growth across much of the northern hemisphere have been interpreted as responses to warming. However, several kinds of environmental change hav...

2015
D. Scott Mackay David E. Roberts Brent E. Ewers John S. Sperry Nathan G. McDowell William T. Pockman

Hydraulic systems of plants have evolved in the context of carbon allocation and fitness tradeoffs of maximizing carbon gain and water transport in the face of short and long-term fluctuations in environmental conditions. The resulting diversity of traits include a continuum of isohydry-anisohydry or high to low relative stomatal closure during drought, shedding of canopy foliage or disconnecti...

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