Search results for "botany"
showing 10 items of 4586 documents
Trophic habits of Muscardinus avellanarius (Mammalia Gliridae) as revealed by multiple stable isotope analysis
2007
Multiple stable isotope analysis was used to investigate the diet of the common dormouse Muscardinus avellanarius in a mixed Mediterranean forest. δ13C and δ15N values of dormouse tissues compared to those of the vegetal and animal sources available in the area showed that the isotopic composition of both adult and juvenile M. avellanarius could be explained by a mixture of vegetal and animal organic matter. The isotopic composition of the assimilated nitrogen was mostly explained by the organic matter from flora. Among the vegetal components, flowers of Fagus silvatica, Quercus robur, and the rarer Crataegus oxyacantha, berries of Ilex aquifolium and acorns of Q. robur were found in the ad…
Effect of Temperature on Isobutyric Acid Loss during Roasting of Carob Kibble
1997
The high content of isobutyric acid in carob (Ceratonia siliqua L.) constitutes a handicap for some of its potential uses due to the undesirable smell produced by that compound. In this study the loss of isobutyric acid during roasting was approached by heating the carob kibble at temperatures from 120 to 180 °C in two local cultivars (Matalafera and Lisa). The initial content of isobutyric acid varied between 6.3 (Lisa) and 9.4 (Matalafera) g isobutyric acid/kg dry solid. Results showed that the process can be described by a diffusive model. The activation energy of the process is about 55 kJ/mol for both cultivars. Keywords: Carob pod; roasting; isobutyric acid; diffusion
The Effect of Bialaphos on Ammonium-Assimilation and Photosynthesis II. Effect on Photosynthesis and Photorespiration
1989
Abstract The application of bialaphos (phosphinothricyl-alanyl-alanine) effects a quick photosynthesis inhibition under atmospheric conditions (400 ppm CO2, 21% O2). However, under conditions (1000 ppm CO2, 2% O2) under which photorespiration cannot occur there is no photosynthesis inhibition. In the previous investigation it could be shown that bialaphos splits in plants into phosphinothricin and alanine. The inhibition of glutamine synthetase through freed phosphinothricin results in an NH4 +-accumulation and a decrease in glutamine. With the addition of glutamine, photosynthesis inhibition by bialaphos can be reduced. An NH4 +-accumulation takes place under atmospheric conditions as well…
Two guaianolides from Centaurea collina
1987
Abstract Two guaianolides isolated from the aerial parts of Centaurea collina were identified as 3β-hydroxy-8α-epoxymethylacriloiloxy-4(15),10(14),11(13 and its 11β,13-dihydro derivative by spectroscopic methods.
Effects of drying temperatures on physico-chemical properties of dried and rehydrated chestnuts (Castanea sativa)
2004
This work evaluated the effects of two drying temperatures (40 and 60 degreesC) on some physical and chemical properties of chestnuts, both dried and after their rehydration using steam at 100 degreesC. The morphological characteristics of fresh starch granules were characterized by a round or oval shape, with diameter length ranging from 3.0. to 15.0 mum. After drying and rehydration, the granules appeared more shapeless and the surfaces were quite rough. The changes also caused more of the open pore volume fraction in samples dried at 60 degreesC, than in those dried at 40 degreesC and, much more, than the fresh samples. Also, calorimetric behaviour, starch and simple sugar changes after …
Crown ethers derived from cyclohexane. Influence of their stereochemistry in complexation and transport
2002
Abstract Crown ethers derived from cyclohexane have been prepared. The trans stereochemistry of the substituents on the carbocyclic ring makes that only one conformation can complex cations. The influence of the stereochemistry in complexation has been studied.
Soda-AQ pulping of reed canary grass
2001
Abstract Delignification of reed canary grass (Phalaris arundinacea L.) was carried out by conventional soda-anthraquinone (AQ) pulping under varying conditions selected according to an orthogonal experimental design with four factors (cooking parameters) at three levels each L9 (34). The influence of these four parameters, i.e. effective alkali, EA (12, 15, and 18% on oven dried (o.d.) reed, as NaOH), maximum temperature (145, 155, and 165°C), time to maximum temperature (70, 90, and 110 min), and time at maximum temperature (0, 15, and 30 min) on the pulp properties (yield, kappa number, and viscosity) was studied. Results indicated that, with respect to delignification, EA was the most i…
A sesquiterpene ester from Lactuca serriola
1992
Abstract The aerial parts of Lactuca serriola yielded a new guaiane ester together with five known guaianolides.
Photoassimilate Regulation of Sorbitol and Sucrose Metabolism in Peach Fruit
2005
Along with sucrose, sorbitol represents the major photosynthetic product and the main form of translocated carbon in peach. The objective of the present study was to determine whether in peach fruit, sorbitol and sucrose enzyme activities are source-regulated, and more specifically modulated by sorbitol or sucrose availability. In two separate trials, peach fruit relative growth rate (RGR), enzyme activities, and carbohydrates were measured 1) at cell division stage before and after girdling of the shoot subtending the fruit; and 2) on 14 shoots with different leaf to fruit ratio (L:F) at cell division and cell expansion stages. Fruit RGR and sorbitol dehydrogenase (SDH) activity were signi…
Soil‐plant relationships, micronutrient contents, and cardenolide production in natural populations of Digitalis obscura
2004
The production of secondary metabolites by plants growing in natural populations is conditioned by environmental factors. In the present study, we have investigated the relationships among soil properties, micronutrients in soils and plants, and cardenolide production from wild Digitalis obscura (Scrophulariaceae) populations. Young and mature leaves and soil samples were collected in ten different populations, corresponding to three Mediterranean bioclimatic belts (Thermo-, Meso-, and Supramediterranean belts). Soil (total and EDTA-extractable) and leaf micronutrients (Fe, Mn, Zn, and Cu), and leaf cardenolide accumulation have been determined. Significant negative correlations were observ…