نتایج جستجو برای: leaf canopy

تعداد نتایج: 96802  

2008
M. A Cho J. de Leeuw

Developments in hyperspectral remote sensing have provided new indices or indicators of biochemical and biophysical properties. Most of the studies involving the novel spectral indices have been conducted at the leaf scale and have been rarely investigated for species discrimination. The objectives of the study were to determine hyperspectral indices that (i) are likely to be influenced by chan...

Journal: :Tree physiology 2002
Robert M Hubbard Barbara J Bond Randy S Senock Michael G Ryan

Recent studies have shown that stomata respond to changes in hydraulic conductance of the flow path from soil to leaf. In open-grown tall trees, branches of different heights may have different hydraulic conductances because of differences in path length and growth. We determined if leaf gas exchange, branch sap flux, leaf specific hydraulic conductance, foliar carbon isotope composition (delta...

Journal: :Journal of experimental botany 2000
G Deckmyn I Nijs R Ceulemans

There are several very accurate methods to determine leaf angles in closed canopies. However, these are generally very time-consuming or require special equipment. Average canopy leaf angles were derived from simple height and blade length measurements. An exponential relationship between the height/length ratio and the average blade leaf angle was used. The method was tested for two grass spec...

2008
José Enrique Fernández Antonio Diaz-Espejo Roberto Tognetti JOSÉ ENRIQUE FERNÁNDEZ ANTONIO DIAZ-ESPEJO RICCARDO D’ANDRIA LUCA SEBASTIANI ROBERTO TOGNETTI

Data from Spanish and Italian olive orchards with different cultivars (‘‘Manzanilla’’, ‘‘Frantoio’’, ‘‘Leccino’’, ‘‘Razzola’’ and ‘‘Taggiasca’’) growing in different environments (southern Spain; north, centre and south of Italy) were used to illustrate how models on water use and photosynthetic behaviour of the olive tree can be useful tools for choosing pruning intensity and canopy shape for ...

Journal: :The New phytologist 2010
Mashuri Waite Lawren Sack

Mosses are an understudied group of plants that can potentially confirm or expand principles of plant function described for tracheophytes, from which they diverge strongly in structure. We quantified 35 physiological and morphological traits from cell-, leaf- and canopy-level, for 10 ground-, trunk- and branch-dwelling Hawaiian species. We hypothesized that trait values would reflect the disti...

2006
Dong Huang Yuri Knyazikhin Robert E. Dickinson Miina Rautiainen Pauline Stenberg Mathias Disney Philip Lewis Alessandro Cescatti Yuhong Tian Wout Verhoef John V. Martonchik Ranga B. Myneni

The concept of canopy spectral invariants expresses the observation that simple algebraic combinations of leaf and canopy spectral transmittance and reflectance become wavelength independent and determine a small set of canopy structure specific variables. This set includes the canopy interceptance, the recollision and the escape probabilities. These variables specify an accurate relationship b...

Journal: :Annals of botany 2005
Kouki Hikosaka

BACKGROUND AND AIMS In a leaf canopy, there is a turnover of leaves; i.e. they are produced, senesce and fall. These processes determine the amount of leaf area in the canopy, which in turn determines canopy photosynthesis. The turnover rate of leaves is affected by environmental factors and is different among species. This mini-review discusses factors responsible for leaf dynamics in plant ca...

Journal: :Plant physiology 2008
Johannes Kromdijk Hans E Schepers Fabrizio Albanito Nuala Fitton Faye Carroll Michael B Jones John Finnan Gary J Lanigan Howard Griffiths

Perennial species with the C(4) pathway hold promise for biomass-based energy sources. We have explored the extent that CO(2) uptake of such species may be limited by light in a temperate climate. One energetic cost of the C(4) pathway is the leakiness () of bundle sheath tissues, whereby a variable proportion of the CO(2), concentrated in bundle sheath cells, retrodiffuses back to the mesophyl...

Journal: :Plant physiology 2008
Jessica Bertheloot Pierre Martre Bruno Andrieu

In monocarpic species, during the reproductive stage the growing grains represent a strong sink for nitrogen (N) and trigger N remobilization from the vegetative organs, which decreases canopy photosynthesis and accelerates leaf senescence. The spatiotemporal distribution of N in a reproductive canopy has not been described in detail. Here, we investigated the role of the local light environmen...

2015
K. D. Maurer

Surface roughness parameters, namely the roughness length and displacement height, are an integral input used to model surface fluxes. However, most models assume these parameters to be a fixed property of plant functional type and disregard the governing structural heterogeneity and dynamics. In this study, we use large-eddy simulations to explore, in silico, the effects of canopy-structure ch...

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