نتایج جستجو برای: leaf spectra
تعداد نتایج: 193027 فیلتر نتایج به سال:
ZnS nanoparticles have been synthesized using various amounts of aqueous Azadirachta Indica (Neem) leaf extract as capping agent and stabilizer. The synthesized nanoparticles were studied by FTIR, powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive analysis of X-rays (EDAX) and UV-Visible spectroscopy. FTIR spect...
Fourier transform infrared (FTIR) spectroscopy has the ability to quickly identify the presence of specific carbohydrates in plant materials. The presence of the disease huanglongbing (HLB) in the leaves of infected citrus plants has a distinctive spectrum that can be used to distinguish an infected plant from a healthy plant. However, many citrus diseases display similar visible symptoms and a...
This paper presents a first analysis of MERIS-Full Resolution (FR) data to observe seasonal variations of the reflectances of agricultural fields in two regions with different climatic conditions: Toulouse (France) and Barrax (Castilla-La Mancha, Spain). The objective is to assess the capabilities of MERIS for crop monitoring. After applying an atmospheric correction method to the images we hav...
Although there have been several studies on the spectral characteristics related to leaf water content, it remains unclear whether the spectral property of leaves can be extended to the canopy-level. In this study, we attempt to compare the spectral characteristics of forest vegetation in moderate drought condition observed by laboratory measurement and satellite hyperspectral image data. Spect...
Precision agriculture, forestry and environmental remote sensing are applications uniquely suited to the 8 bands that DigitalGlobe’s WorldView-2 provides. At the fine spatial resolution of 0.5 m (panchromatic) and 2 m (multispectral) individual trees can be readily resolved. Recent research [1] has shown that it is possible for hyperspectral data to invert plant reflectance spectra and estimate...
A red/purple coloration of lower (abaxial) leaf surfaces is commonly observed in deeply-shaded understorey plants, especially in the tropics. However, the functional significance of red abaxial coloration, including its role in photosynthetic adaptation, remains unclear. The objective of this study was to test the back-scatter hypothesis for abaxial leaf coloration, which posits that red pigmen...
The position of the inflexion point in the red edge (680 nm to 780 nm), termed the red-edge position (REP) has been used as a measure to estimate foliar chlorophyll or nitrogen content. In this study, we assessed the utility of a new technique for extracting the REP, the linear extrapolation method recently proposed by Cho and Skidmore [Remote Sens. Environ. (in press)]. The assessment was base...
Leaf and stem essential oils of Lonchocarpus cyanescens Benth., (Fabaceae) were obtained by hydro-distillation, using all-glass apparatus adapted to British Pharmacopeia specifications with yields of 0.03% and 0.17% respectively. The oils were investigated by GC and GC-MS analyses. Results show seven compounds were responsible for 90.4% of leaf; eleven compounds responsible for 97.6% of stem vo...
Forest understories play a vital role in ecosystem functioning and the provision of services. However, extent to which environmental conditions drive dominant ecological strategies forest at continental scale remains understudied. Here, we used ~29 500 vegetation plots sampled across Europe classified into 25 types explore relative macroclimate, soil pH tree canopy cover driving abundance-weigh...
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