نتایج جستجو برای: transpiration

تعداد نتایج: 4618  

2015
Brandon McNellis Ava R Howard

Nighttime transpiration is a substantial portion of ecosystem water budgets, but few studies compare water use of closely related co-occurring species in a phylogenetic context. Nighttime transpiration can range up to 69% of daytime rates and vary between species, ecosystem, and functional type. We examined leaf-level daytime and nighttime gas exchange of five species of the genus Rubus co-occu...

Journal: :Plant physiology 1984
M E Westgate J S Boyer

Recent evidence from leaves and stems indicates that gradients in water potential (psi(w)) necessary for water movement through growing tissues are larger than previously assumed. Because growth is sensitive to tissue psi(w) and the behavior of these gradients has not been investigated in transpiring plants, we examined the water status of all the growing and mature vegetative tissues of maize ...

Journal: :journal of agricultural science and technology 2015
s. segura-monroy a. uribe-vallejo a. ramirez-godoy h. restrepo-diaz

the anatomical and epidermal characteristics, as well as the physiological response, of 'colombia' ecotype cape gooseberry plants treated or untreated with foliar applications of kaolin at 2 irrigation levels (well-irrigated plants vs. water-stressed plants) were evaluated. relative water content (rwc), stomatal density, and chlorophyll index were reduced under water stress. water stress increa...

N. Rahimzadeh Halagh S.H.R. Sadeghi,

Transpiration, as one of the components of hydrological cycle, has not been paid enough attention yet, while it is necessary for sound utilization of rangelands, mostly located in the arid and semiarid regions. The comparison of the different kinds of rangelands species in terms of transpiration rates provides range managers the required information to achieve optimal forage production for a gi...

2002
Alexander Oltchev Jan Cermak Nadezhda Nadezhdina

Transpiration of a mixed spruce-aspen-birch forest at the Valday Hills in Russia was determined using sap fl ow measurements and two different SVAT (Soil–Vegetation–Atmosphere-Transfer) models. The more sophisticated Mixed Forest multi-layer SVAT model (MF-SVAT) considers water uptake and transpiration of each tree species individually, and the simple Multi-Layer (ML-SVAT) describes the forest ...

2011
G. W. Moore J. A. Jones B. J. Bond

The water balance equation dictates that streamflow may be reduced by transpiration. Yet temporal disequilibrium weakens the relationship between transpiration and streamflow in many cases where inputs and outputs are unbalanced. We address two critical knowledge barriers in ecohydrology with respect to time, scale dependence and lags. Study objectives were to correlate components of the water ...

2006
Graham D. Farquhar Lucas A. Cernusak Belinda Barnes

A small proportion of water molecules contain the heavier isotopes of hydrogen and oxygen. There is a tendency for these heavier molecules of water to accumulate in leaves during transpiration. This has several interesting repercussions, including effects on the isotopic composition of organic matter, and of atmospheric water vapor, carbon dioxide, and oxygen. In turn, these effects aid tempora...

2007
S. Samanta D. S. Mackay M. K. Clayton E. L. Kruger B. E. Ewers

[1] A Bayesian approach was used to fit a conceptual transpiration model to half-hourly transpiration rates for a sugar maple (Acer saccharum) stand collected over a 5-month period and probabilistically estimate its parameter and prediction uncertainties. The model used the Penman-Monteith equation with the Jarvis model for canopy conductance. This deterministic model was extended by adding a n...

Journal: :مرتع و آبخیزداری 0
کاظم نصرتی دانشیار دانشکدة علوم زمین دانشگاه شهید بهشتی محسن محسنی ساروی استاد دانشکدة منابع طبیعی دانشگاه تهران حسن احمدی استاد دانشکدة منابع طبیعی دانشگاه تهران حسین عقیقی کارشناس پژوهشی سازمان فضایی ایران

estimation of evapo-transpiration is necessary in cases such as irrigation planning, determining of evaporation of the water bodies, water balance assessment, estimation of runoff and watershed management and ecological and meteorological studies. evapo-transpiration can be determined precisely using field measurements. however, these methods provide evapo-transpiration just for limited areas f...

Journal: :Tree physiology 2007
Fabian G Scholz Sandra J Bucci Guillermo Goldstein Frederick C Meinzer Augusto C Franco Fernando Miralles-Wilhelm

Under certain environmental conditions, nocturnal transpiration can be relatively high in temperate and tropical woody species. We have previously shown that nocturnal sap flow accounts for up to 28% of total daily transpiration in woody species growing in a nutrient-poor Brazilian Cerrado ecosystem. In the present study, we assessed the effect of increased nutrient supply on nocturnal transpir...

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