Search results for "dry weight"
showing 10 items of 101 documents
Sediment-associated retene bioavailability of sediment-associated retene to an oligochaete wormlumbriculus variegatus
2001
The bioavailability of retene spiked to two sediment concentrations (50 and 200 µg/g dry weight) was measured in long-term (28-day) bioaccumulation tests performed on the oligochaeteLumbriculus variegatus Muller. Three sediment organic carbon (SOC) concentrations (1.1, 3.0, 23.0% of dry weight) were used. Growth and reproduction, used as endpoints, indicated that retene was chronically nontoxic at the concentrations employed. Retene was clearly bioavailable, but bioaccumulated about 100 times less in the SOC-rich (23.0%) sediment than in the other two (SOC <3.0%). At the lower retene concentration, retene in the worms was undetectable in the high-SOC sediment. Based on final retene present …
Chemical composition of the essential oil of Phagnalon saxatile (L.) Cass. (Asteraceae) growing wild in Southern Italy
2005
Abstract The essential oil from aerial parts of Phagnalon saxatile (L.) Cass. (Asteraceae) was obtained by hydrodistillation. The oil content was 0.15% (v/w), on a dry weight basis. The oil composition was analyzed by GC and GC/MS. Altogether 66 compounds were identified accounting for 93.2% of the oil. Sesquiterpenes represent the 23.9% of the oil. In the oil were also present fatty acids (21.8%) and waxes (19.3%). The oil shows no antibacterial activity.
Effect of a physical pre-treatment and drying on carotenoids of goji berries ( Lycium barbarum L.)
2018
In order to evaluate the influence of an abrasive pre-treatment and drying at 50 °C, 60 °C, 70 °C of goji fruits (Lycium barbarum L.), changes in colour and carotenoids were studied. An extraction method was modified and adapted to assay the main carotenoid esters and saponified carotenoids of goji berries, before and after treatments. Goji berries were confirmed as a high source of zeaxanthin, with zeaxanthin-dipalmitate at about 2 g/kg dry weight. The reliability of the analytical method was confirmed by the high quantitative recoveries, about 100%, a higher repeatability than reference methods and a good reproducibility (lower than 5%). After drying, significant but small carotenoid loss…
Impact of a new bio-pesticide produced by Paenibacillus sp. strain B2 on the genetic structure and density of soil bacterial communities
2007
The effect of paenimyxin, a new biopesticide produced by Paenibacillus sp. strain B2, on the density of soil bacterial communities was assessed by colony counting and by 16S rDNA and nirK quantitative polymerase chain reaction (PCR). Paenimyxin had a negative effect on the bacterial colony-forming unit (CFU) number, which was significantly reduced 2 and 4 days after treatment. The effect of paenimyxin on cultivatable bacteria was negligible 7 days after treatment. Approximately 107 16S rDNA sequences per gram of soil (dry weight) were detected by quantitative PCR in all samples. Paenimyxin did not affect the quantification of 16S rDNA or of the denitrifying bacterial community. In addition,…
Seasonal pattern of mannitol and malate accumulation in leaves of two manna ash species (Fraxinus ornusL. andF. angustifoliaVahl) growing in Sicily
2002
ABSTRACT The content of mannitol and malate was assayed enzimatically during spring, summer and autumn, in leaves of two species of ash, Fraxinus ornus L. and Fraxinus angustifolia Vahl, traditionally cultivated in Sicily for the extraction of manna. Both species contain high levels of mannitol and show, on a dry weight basis, a 65–80% increase in the summer content of this polyol. The malate content differs in the two species: in F. ornus it shows a summer increase, but it is relatively low (65–115 µmol g-1 DW), while in F. angustifolia it is higher (275–318 µmol g-1 DW), but remains more or less constant throughout the year. The results suggest that in these species, under the local field…
Metarhizium anisopliae, a potential agent for the control of grape phylloxera
2004
This investigation deals with the control effects of the insect pathogenic fungus Metarhizium anisopliae var. anisopliae on Daktulosphaira vitifoliae. In pot experiments, the soil surrounding phylloxera-infected grapes was inoculated with barley colonised with M. anisopliae. After thirty-two days, ineight of ten Metarhizium-applied pots nofresh phylloxera infections could be observed.In two of ten plants, a few fresh nodositiessingly occupied with phylloxera or phylloxeraeggs could be found. In all untreated plants,fresh nodosities with either single (two of sixplants) or multiple (four of six plants)occupation with phylloxera could be observed.M. anisopliae could be re-isolated in aconcent…
Lipid accumulation inTrichodermaspecies
1992
Two filamentous fungi, Trichoderma harzianum and Trichoderma viride, were compared for their ability to synthesize lipids on different carbon and nitrogen sources. Three culture media were selected for each strain after preliminary screening. All the test media were nitrogen-deficient (C/N = 60) so as to stimulate lipid accumulation. For both microorganisms the glucose-ammonium sulphate medium was the most conducive to lipid production: a lipid accumulation of 17% (w/w) of biomass dry weight was obtained for T. harzianum and of 32% (w/w) of biomass dry weight for T. viride. In sucrose-sodium nitrate medium T. harzianum was able to accumulate almost 25% (w/w) of its biomass in lipid form. Ho…
The relationship of hydraulic conductance to root system characteristics of peach (Prunus persica) rootstocks
2006
Specific rootstocks can differentially influence the vegetative growth and development of fruit trees. However, the physiological mechanism involved in this phenomenon has been elusive. Recent research comparing different peach (Prunus persica L. Batsch) rootstocks suggests that the rootstock effect on vegetative growth in peach trees is associated to water relations and more specifically to differences in rootstock hydraulic conductance. This study was intended to confirm differences in hydraulic characteristics of similar size peach trees grafted on different rootstocks and to examine root system characteristics that could be associated with rootstock hydraulic limitations. Trees on roots…
Growth analysis and mineral content in pistachio (Pistacia veraL.) infructescence and its components
1996
SummaryGrowth and seasonal variation in mineral content was described for infructescence components of ‘Bianca’ pistachio cultivar grafted onto Pistacia therebintus L. The absorption curve specific to each infructescence and fruit component was calculated on a percent dry weight and an absolute content basis. Nutrient uptake by infructescence components was consistent with their development rate. The embryo was the strongest sink for N, P and Mg uptake. Pericarp and rachis accounted for more than 80% of K and Ca accumulated in the infructescence. The highest accumulation rate occurred during rapid embryo growth.
Association of Marginal Leaf Scorch with Sodium Accumulation in Salt-stressed Peach
2000
The effect of specific ion toxicity during salt stress was tested in the present study. The experiment was repeated twice, in 1996 and 1998, with `Nemaguard' peach seedlings and rooted cuttings grown in hydroponics under two NaCl concentrations (50 and 30 mm). Foliage was separated in symptomatic and symptomless leaves and the amount of sodium (Na+) and chloride (C1–) was determined. Significantly higher Na+ content was found in symptomatic than in symptomless leaves in both experiments, whereas in only two of the six cases was Cl– content higher in symptomatic than in symptomless leaves. The Na+ threshold for leaf scorch was somewhere between 4 and 6 mg·g–1 dry weight. Results indicated th…