Search results for "botany"
showing 10 items of 4586 documents
Transparency reduces predator detection in mimetic clearwing butterflies
2019
International audience; Predation is an important selective pressure and some prey have evolved conspicuous warning signals that advertise unpalatability (i.e. aposematism) as an antipredator defence. Conspicuous colour patterns have been shown effective as warning signals, by promoting predator learning and memory. Unexpectedly, some butterfly species from the unpalatable tribe Ithomiini possess transparent wings, a feature rare on land but common in water, known to reduce predator detection.We tested if transparency of butterfly wings was associated with decreased detectability by predators, by comparing four butterfly species exhibiting different degrees of transparency, ranging from ful…
Hieracium umbrosum subsp. abietinum (Asteraceae), a further example of amphi-Adriatic disjunction
2017
So far considered as endemic to Greece, Hieracium umbrosum subsp. abietinum is reported as new for the Italian flora. Its presence has been noted on the Pollino National Park (S Italy). Morphological, ecological and taxonomical notes are given. This discovery increases the list of taxa showing an amphi-Adriatic distribution.
Inferring Phytoplankton, Terrestrial Plant and Bacteria Bulk δ¹³C Values from Compound Specific Analyses of Lipids and Fatty Acids.
2015
Stable isotope mixing models in aquatic ecology require δ13C values for food web end members such as phytoplankton and bacteria, however it is rarely possible to measure these directly. Hence there is a critical need for improved methods for estimating the δ13C ratios of phytoplankton, bacteria and terrestrial detritus from within mixed seston. We determined the δ13C values of lipids, phospholipids and biomarker fatty acids and used these to calculate isotopic differences compared to the whole-cell δ13C values for eight phytoplankton classes, five bacterial taxa, and three types of terrestrial organic matter (two trees and one grass). The lipid content was higher amongst the phytoplankton (…
Adventiv-Embryonen aus Nicotiana-kallus, der bei Hohen Lichtintensitäten Kultiviert wurde
1965
The formation of embryonic structures in Nicotiana callus tissue has been reported. High intensity of light as a stimulating factor in differentiation is discussed.
Ginger and Turmeric Essential Oils for Weed Control and Food Crop Protection
2019
Ginger and turmeric are two food ingredients that are in high demand due to their flavor and positive effects on health. The biological properties of these spices are closely related to the aromatic compounds they contain. The chemical compositions of their essential oils and their in vitro phytotoxic activity against weeds (Portulaca oleracea, Lolium multiflorum, Echinochloa crus-galli, Cortaderia selloana, and Nicotiana glauca) and food crops (tomato, cucumber, and rice) were studied. Forty-one compounds, accounting for a relative peak area of 87.7% and 94.6% of turmeric and ginger essential oils, respectively, were identified by Gas Chromatography&ndash
Agronomical evaluation of Sicilian biotypes of Lavandula stoechas L. spp. stoechas and analysis of the essential oils
2015
The aim of this study was to characterize wild lavender, which was collected in three different areas of Sicily (Italy),according to agronomic and chemical evaluation. The collection sites were located in Pantelleria island, Partinico (a warm sub-area of Lauretum) and Castelbuono (a middle sub-area of Lauretum). All the populations were identified as Lavandula stoechas L. ssp. stoechas. Essential oils were extracted by hydrodistillation and analyzed by gas chromatography– flame ionization detector (GC–FID) and GC–mass spectrometry (GC–MS). GC–FID and GC–MS analyses permitted the identification of 101 components from the essential oils. We analyzed only the flowers and leaves of L. stoechas …
Study of quantitative and qualitative variations in essential oils of Sicilian oregano biotypes
2015
Essential oil (EO) was extracted using hydrodistillation from samples of Origanum vulgare subspecies hirtum (Link) Ietswaart, gathered from the wild in various parts of Sicily, Italy; GC-FID and GC-MS analyses were subsequently performed. The aim of the study was to analyze the relationship between essential oil yields and the geographical distribution of oregano wild populations based on variations in environmental factors as collection sites. Moreover, the purpose was to group Origanum vulgare subspecies hirtum biotypes according to the chemical composition of the EO. The seven principal components in the EO was thymol (24.0–54.4%), γ-terpinene (9.8–30.5%), ρ-cymene (5.2–18.7%), α-terpine…
Les grands types de sols viticoles de Pomerol et Saint-Emilion
1978
<p style="text-align: justify;">Les vins les plus réputés de la région viticole de Pomerol et Saint-Emilion sont produits sur des sols foncièrement différents, dérivant de roches mères présentant une grande diversité.</p><p style="text-align: justify;">Les variations que l'on peut noter d'un cru à l'autre sont liées, non pas aux caractéristiques chimiques de ces sols, mais surtout à leurs propriétés physiques (texture, structure, porosité, perméabilité) avec leurs conséquences sur le mode et la profondeur de l'enracinement.</p><p style="text-align: justify;">+++</p><p style="text-align: justify;">The most famous wines from the wine-growing region of…
Effet colloide-protecteur d'extraits de parois de levures sur la stabilité tartrique d'une solution hydro-alcoolique modèle
1993
<p style="text-align: justify;">L'effet colloïde-protecteur d'extraits mannoprotéiques de parois de levures vis-à-vis de la précipitation tartrique a été étudié en solution hydroalcoolique, en utilisant un IST mètre (Indice de Stabilité Tartrique).</p><p style="text-align: justify;">Nous avons montré que les deux extraits levuriens inhibaient la cristallisation du bitartrate de potassium au même titre que l'acide métatartrique et la carboxyméthylcellulose, mais à un niveau plus faible. Le niveau de stabilité retenu (ISTC-75) est assuré avec des concentrations par litre de 7,5 mg d'acide métatartrique et de 18 mg de carboxyméthylcellulose. Des concentrations en extraits man…
Terrestrial carbohydrates support freshwater zooplankton during phytoplankton deficiency
2016
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