Search results for "leaf"

Optimizing LUT-Based RTM Inversion for Semiautomatic Mapping of Crop Biophysical Parameters from Sentinel-2 and -3 Data: Role of Cost Functions

2014

Inversion of radiative transfer models (RTM) using a lookup-table (LUT) approach against satellite reflectance data can lead to concurrent retrievals of biophysical parameters such as leaf chlorophyll content (Chl) and leaf area index (LAI), but optimization strategies are not consolidated yet. ESA's upcoming satellites Sentinel-2 (S2) and Sentinel-3 (S3) aim to ensure continuity of old generation satellite sensors by providing superspectral images of high spatial and temporal resolution. This unprecedented data availability leads to an urgent need for developing robust, accurate, and operational retrieval methods. For three simulated Sentinel settings (S2-10 m: 4 bands, S2-20 m: 8 bands an…

What do leaf anatomy and micromorphology tell us about the psammophilous Pancratium maritimum (Amaryllidaceae) in response to sand dune conditions?

2015

Abstract The present study aimed at verifying the morphological variation in leaf traits among different populations of Pancratium maritimum (sea daffodil) and the correlation between leaf diversity and climate conditions at different sites. Eleven populations of P. maritimum from Mediterranean coastal sand dunes were investigated with respect to leaf surface micro-morphology, leaf anatomy, and vascular pattern. Morphometric analysis was based on 29 quantitative foliar parameters. One-way analysis of variance (ANOVA), principal component analysis (PCA), discriminant function analysis (DFA), and clustering by Ward’s method were used for the statistical evaluation. Results revealed a rather u…

Morphological observations on the co-occurring geophytes Isoetes duriei Bory (Lycophyta, Isoetaceae) and Romulea columnae Sebast. et Mauri (Anthophyt…

2003

Some preliminary observations on the morphoplogy and leaf anatomy of two geophytes, Isoetes duriei and Romulea columnae, co-occurring in a Mediterranean temporary pond, have been reported. The species examined possess characters favourable to the survival of both flooded and arid conditions. The adaptive traits to flooding appear plastic in R. columnae, while I. duriei is “structurally” an aquatic plant. Evolutionary and ecological aspects are briefly discussed.

Casparian Strips in the Leaf Intrastelar Canals of Isoetes duriei Bory, a Mediterranean Terrestrial Species

2000

Abstract Anatomical observations, using light and fluorescence microscopy, were made on leaves of Isoetes duriei to verify the presence of casparian bands around the intrastelar canals. This peculiar anatomical feature, previously reported for some Isoetes species, is confirmed. The possible role of this endodermis-like structure, in the transport of water due to root pressure or in the accumulation of certain metabolites, is discussed in relation to the ecological and anatomical features of the species.

Retrieving leaf area index from multi-angular airborne data

2009

This work is aimed to demonstrate the feasibility of a methodology for retrieving bio-geophysical variables whilst at the same time fully accounting for additional information on directional anisotropy. A model-based approach has been developed to deconvolve the angular reflectance into single landcovers reflectances, attempting to solve the inconsistencies of 1D models and linear mixture approaches. The model combines the geometric optics of large scale canopy structure with principles of radiative transfer for volume scattering within individual crowns. The reliability of the model approach to retrieve LAI has been demonstrated using data from DAISEX- 99 campaign at Barrax, Spain. Airborn…

Sensitivity analysis on the relationship between vegetation growth and multi-polarized radar data

2009

Spatially distributed soil moisture is required for watershed applications such as drought and flood prediction, crop irrigation scheduling, etc. In particular, an accurate assessment of the spatial and temporal variation of soil moisture is necessary to improve the predictive capability of runoff models, and for improving and validating hydrological processes forecasting. In recent years, several models have been developed in order to retrieve soil moisture using RADAR data. However, these models need precise prior knowledge about surface roughness. Within this framework, the present research aims to investigate the capabilities of multi polarimetric RADAR images to overcome the use of in …

A new species of Allium (Alliaceae) from Dalmatia, Croatia

2008

Abstracts, XI OPTIMA meeting .Beograd 5–11. IX. 2004. Belgrade: Natural HistoryMuseum, 122. Brullo S, Guglielmo A, Pavone P, Salmeri C. 2007. Cytotaxonomic considerations on Allium stamineum Boiss.group (Alliaceae). Bocconea 21: 325–343. Diez MJ. 1987. Liliaceae. In: Valdes B, Diez MJ, FernandezI, eds. Atlas Polinico de Andalucia Occidental . Instituto deDesarrollo Regional. Sevilla: Universidad de Sevilla, Exce-lentisima Diputacion Provincial de Cadiz, 379–395. D’Ovidio R, Marchi P. 1990. DNA content, karyotype struc-ture analysis and karyotype symmetry in Ranunculus L.(Ranunculaceae) Italian species belonging to sections Flam-mula (Webb) Benson and Micranthus (Ovcz.) Nyarady. Caryologia 4…

Natural Hosts and Genetic Diversity of the Emerging Tomato Leaf Curl New Delhi Virus in Spain

2019

Knowledge about the host range and genetic structure of emerging plant viruses provides insights into fundamental ecological and evolutionary processes, and from an applied perspective, facilitates the design and implementation of sustainable disease control measures. Tomato leaf curl New Delhi virus (ToLCNDV) is an emerging whitefly transmitted begomovirus that is rapidly spreading and inciting economically important diseases in cucurbit crops of the Mediterranean basin. Genetic characterization of the ToLCNDV Mediterranean populations has shown that they are monophyletic in cucurbit plants. However, the extent to which other alternative (cultivated and wild) hosts may affect ToLCNDV genet…

A giant left atrium in a patient with Barlow syndrome, abnormal chordae tendineae, and perforation of the anterior mitral leaflet

2019

Leaf water potential meaning of different modalities of measurements

2004

<p style="text-align: justify;">An experiment on Syrah in the Ecotron design of the AGRO Montpellier/INRA campus vineyard, with the control of different water regimes, allowed to test the physiological meaning and the field of application of different modalities of leaf water potential measurements : predawn and daily potential for leaves in a normal micro-environment (which keep all of their interest and generality), « stem » potential (which must be called differently and reserved to particular conditions) for shadow enveloped leaves. Field observations on Syrah and Merlot confirm the interest of some methods.</p>