نتایج جستجو برای: leaf canopy

تعداد نتایج: 96802  

2016
Isabelle Maréchaux Megan K. Bartlett Philippe Gaucher Lawren Sack Jérôme Chave

Amazonian tree communities have already been seriously impacted by extreme natural droughts, and intense droughts are predicted to increase in frequency. However, our current knowledge of Amazonian tree species’ responses to water stress remains limited, as plant trait databases include few drought tolerance traits, impeding the application and predictive power of models. Here we explored how l...

2006

The effects of CO2 enrichment on the growth and physiology of maize were investigated at the molecular, biochemical, leaf, and canopy levels. Maize plants were grown in sunlit soil–plant–atmosphere research (SPAR) chambers at ambient (370 lmol mol ) or elevated (750 lmol mol ) atmospheric carbon dioxide concentration (Ca) under wellwatered and fertilized conditions. Canopy gas exchange rates an...

2014
Heather V. Graham Mark E. Patzkowsky Scott L. Wing Geoffrey G. Parker Marilyn L. Fogel Katherine H. Freeman

The geologic history of closed-canopy forests is of great interest to paleoecologists and paleoclimatologists alike. Closed canopies have pronounced effects on local, continental and global rainfall and temperature patterns. Although evidence for canopy closure is difficult to reconstruct from the fossil record, the characteristic isotope gradients of the “canopy effect” could be preserved in l...

2014
Xingchang Wang Qinglin Li Albert A. M. Holtslag

The thermally driven wind over mountainous terrains challenges the estimation of CO2 exchange between forests and the atmosphere when using the eddy covariance technique. In this study, the wind regimes were investigated in a temperate deciduous forested valley at the Maoershan site, Northeast China. The wind direction above the canopy was preferentially up-valley in the daytime and down-valley...

Journal: :Plant physiology 2015
Alexandra J Burgess Renata Retkute Michael P Pound John Foulkes Simon P Preston Oliver E Jensen Tony P Pridmore Erik H Murchie

Photoinhibition reduces photosynthetic productivity; however, it is difficult to quantify accurately in complex canopies partly because of a lack of high-resolution structural data on plant canopy architecture, which determines complex fluctuations of light in space and time. Here, we evaluate the effects of photoinhibition on long-term carbon gain (over 1 d) in three different wheat (Triticum ...

2007
Gerardo Avalos Stephen S. Mulkey Kaoru Kitajima Joseph Wright

Lianas impose intense resource competition for light in the upper forest canopy by displaying dense foliage on top of tree crowns. Using repeated access with a construction crane, we studied the patterns of canopy colonization of the lianas Combretum fruticosum and Bonamia trichantha in a Neotropical dry forest in Panama. Combretum fruticosum flushed leaves just before the rainy season, and its...

Journal: :Remote Sensing 2017
Xiaochen Zou Matti Mottus

Leaf inclination angle distribution is an important canopy structure characteristic which directly impacts the fraction of the intercepted solar radiation. Together with the leaf area index (LAI) it determines the structure and fractional cover of a homogeneous crop canopy. Unfortunately, this key canopy parameter has usually been ignored when applying common multispectral vegetation indices to...

2014
Anatoly A. Gitelson Yi Peng Karl F. Huemmrich

Relationship between fraction of radiation absorbed by photosynthesizing maize and soybean canopies and NDVI from remotely sensed data taken at close range and from MODIS 250 m resolution data" a b s t r a c t a r t i c l e i n f o The fraction of incident photosynthetically active radiation absorbed by the photosynthesizing tissue in a canopy (fAPAR) is a key variable in the assessment of vege...

Journal: :Remote sensing of environment 2017
Bin Yang Yuri Knyazikhin Matti Mõttus Miina Rautiainen Pauline Stenberg Lei Yan Chi Chen Kai Yan Sungho Choi Taejin Park Ranga B Myneni

This paper presents the theoretical basis of the algorithm designed for the generation of leaf area index and diurnal course of its sunlit portion from NASA's Earth Polychromatic Imaging Camera (EPIC) onboard NOAA's Deep Space Climate Observatory (DSCOVR). The Look-up-Table (LUT) approach implemented in the MODIS operational LAI/FPAR algorithm is adopted. The LUT, which is the heart of the appr...

2017
Qingfeng Song Yu Wang Mingnan Qu Donald R Ort Xin-Guang Zhu

Canopy photosynthesis (Ac ) describes photosynthesis of an entire crop field and the daily and seasonal integrals of Ac positively correlate with daily and seasonal biomass production. Much effort in crop breeding has focused on improving canopy architecture and hence light distribution inside the canopy. Here, we develop a new integrated canopy photosynthesis model including canopy architectur...

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