1,720,964 research outputs found
Optimising nitrogen in order to improve the efficiency, eco-physiology, yield and quality on one cultivar of durum wheat
Full text linkA 3-year field experiment was carried out in southern Italy to evaluate the effect of different combinations of nitrogen (N) fertilizer rates (0, 55, 90, 135 kg ha–1), time of application (sowing, tillering, stem elongation) and number of nitrogen applications on durum wheat (Triticum turgidum L., var. durum). A total of eight different combinations - in terms of quantity and time of application - were arranged in a randomized complete block design with four replications. Soil plant analysis development was analysed along with leaf area index, grain and straw yield, plant height, plant lodging, thousand-kernel weight, non-vitreous kernels, shrunken and discarded kernels, hectolitre weight, grain protein content, and sodium dodecylsulfate sedimentation. Nitrogen contents of soil, grain and straw were measured in order to assess nitrogen efficiency. The results showed the positive effect of increased nitrogen dosages of 90 and 135 kg ha–1. The optimization of nitrogen administration increased by splitting the nitrogen into three application times, as shown by the eco-physiological, productive and qualitative parameters, and the nitrogen efficiency parameters measured (N application efficiency and N recovery fraction)
Influence of arbuscular mycorrhizae on plant growth, essential oil production and phosphorus uptake of Salvia officinalis L
Full text linkArbuscular mycorrhiza fungi (AMF) contribute to the secondary metabolism and production of active ingredients in aromatic and medicinal plants. This symbiotic association is particularly affected by the availability of phosphorus (P) in the soil. This study was conducted on Salvia officinalis L. using two inocula, commercial Symbivit and Septoglomus viscosum (syn. Glomus viscosum), alone or supplemented with two doses of actual P (0.03, 0.06 g kg−1). The effects of these fungi and their combinations with P were determined in relation to the growth of sage plants (Regula variety), to the concentration of P in leaf tissues, and to the quantity and quality of essential oils (EOs). S. viscosum treated plants showed better growth with or without P-supply compared to non-mycorrhizal plants. The plants inoculated with S. viscosum presented the highest dry weight regardless of addition of P. Both AM fungi increased the leaf P content as more P was applied to the soil, whereas the EO content did not change with any of the treatments. Although the EO yield slightly increased with the Symbivit treatment, the chemical composition of the oil was drastically altered by S. viscosum in which the manool was the main component (28.13%), while -thujone decreased (13.09%). These results suggest that AM symbiosis is a good candidate for promoting plant growth and essential oil composition and for improving P uptake in low fertility soils. Thus, mycorrhiza can be considered as a sustainable strategy based on natural resources in order to influence the manool and -thujone content in sage EO composition. These compositions are very important to develop new classes of biocides and contribute to reducing risks to both human health and the environment
Effects of mycorrhiza on growth and essential oil production in selected aromatic plants
Full text linkArbuscular mycorrhizal (AM) symbiosis is widely investigated in aromatic herbs. Several studies have shown different effects on secondary metabolites, biomass production, as well as oil quantitative and qualitative aspects. The seeking to increase the yield of plants and their oils is an interesting topic in the world of medicinal and aromatic plant production. In tune with that, this study evaluated the effectiveness of two mycorrhiza fungi, Funneliformis mosseae (syn. Glomus mosseae) and Septoglomus viscosum (syn. Glomus viscosum), on three species from Lamiaceae family: Salvia officinalis L., Origanum vulgare L., and Thymus vulgaris L. besides untreated control. It was found that the effect of symbiosis on growth was more favourable with S. viscosum than other AM fungus. The S. viscosum inoculation raised the yield of essential oil in oregano. Analysis of gas chromatography/mass spectrometry showed that manool obtained the highest abundance in leaf essential oil of inoculated sage; thymol was the major component whatever the treatment in thyme and lower relative content of carvacrol was reported with arbuscular mycorrhizal fungi inoculation in oregano. The results suggest the mycorrhizal inoculation as a promising technology in sustainable agricultural system to improve the plant productivity performance. Specific inocula are strategic to enhance the chemical profile of essential oils
Essential oil diversity of Origanum vulgare L. populations from Southern Italy
No full textEssential oils (EOs) belonging to 25 wild populations of Origanum vulgare L. samples, growing wild in different
locations of Calabria Region (Southern Italy), were analyzed using gas chromatography–mass spectrometry.
The quantitative and qualitative data showed EO concentrations ranging from 0.96 to 5.10% and
37 compounds detected, representing more than 80% of the total composition of the oils. By applying
hierarchical cluster analysis on the basis of the EO constituents, two main groups and three subgroups
were found, reflecting the variation in the chemical composition of EOs from wild oregano populations.
The first group consisted of acyclic (linalool/linalyl acetate) chemotypes with a predominant presence of
linalyl acetate; the second was characterized by chemotypes rich in cymyl-compounds, mainly carvacrol,
thymol and c-terpinene.
The data obtained contribute to broaden the inventory of wild oregano populations from Calabria to
plan programs for the selection of chemotypes with new and specific uses
Plant Genetic Resources In Vitro Culture
No full textPlant genetic resources comprise a wide range of plant species, such as herbs, shrubs, and trees, that are of great importance forensuring food, nutrition, and health security. Biotic or abiotic stresses, human activities, and climate change have long threatened the biodiversity in their natural habitat, causing an exponential loss in plant germplasm throughout the world. Thus, there is an urgent need to slow down genetic erosion and support their conservation and sustainable utilization. Advances in biotechnology can generate new opportunities for the rational use and regeneration of valuable plant material by adopting techniques such as in vitro culture and in vitro conservation. The current reprint, "Plant Genetic Resources In Vitro Culture: Present Situation and Prospects for Propagation, Conservation and Sustainable Use", discusses novel approaches toin vitro culture that can positively influence the use of plant genetic resources for biomass or secondary metabolites production, as well as efficient in vitro storage methods and cryopreservation technologies applied to ensure a sustainable supply of high-quality plants as raw materials for different uses
Dynamic and Assembly of Epiphyte and Endophyte Lactic Acid Bacteria During the Life Cycle of Origanum vulgare L
Full text linkOriganum vulgare L. (oregano) was chosen as suitable model to investigate the
ability of the endophyte-microbiome, especially that of lactic acid bacteria, to develop
specific interactions with the plant, mediated by the essential oils (EOs). Combined
culture-dependent and -independent approaches analyzed the bacterial dynamic and
assembly of Origanum vulgare L. throughout the life cycle. Epiphyte bacteria were more
abundant than the endophyte ones. The number of presumptive lactic acid bacteria
increased throughout oregano life cycle, according to the plant organ. Diverse species
of lactic acid bacteria populated the plant, but Lactobacillus plantarum stably dominated
both epiphyte and endophyte populations. High-throughput DNA sequencing showed
highest epiphyte bacterial diversity at early vegetative and full-flowering stages, with
blooming signing the main microbial differentiation among plant organs. Proteobacteria,
Actinobacteria and Bacteroidetes, and Firmicutes and Cyanobacteria at lower
abundance were the main phyla. Various genera were detectable, but oregano
harbored mainly Methylobacterium, Sphingomonas, Rhizobium and Aurantimonas
throughout phenological stages. Firmicutes epiphyte and endophyte microbiotas were
different, with a core microbiota consisting of Bacillus, Exiguobacterium, Streptococcus,
Staphylococcus and Lactobacillus genera. Bacillus dominated throughout phenological
stages. High-throughput DNA sequencing confirmed the dominance of L. plantarum
within the epiphyte and endophyte populations of lactic acid bacteria. Yields of EOs
varied among plant organs and throughout plant life cycle. L. plantarum strains were
the most resistant to the total EOs (mainly thymol and carvacrol) as extracted from
the plant. The positive correlation among endophyte lactic acid bacteria and the EOs
content seems confirm the hypothesis that the colonization within plant niches may be
regulated by mechanisms linked to the synthesis of the secondary metabolites
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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