1,720,979 research outputs found
Desiccation-tolerant Sporobolus stapfianus: lipid composition and cellular ultrastructure during dehydration and rehydration.
No full textThe desiccation-tolerant plant Sporobolus stapfianus
was subjected to slow dehydration and to rehydration
either as a silica gel-dried detached leaf or as an airdried
plant. In detached leaves dehydration resulted
in a lower relative water content in comparison with
leaves dried on the plant. Water loss caused a reduction
in chlorophyll, carotenoid and lipid contents and
an increase in conjugated dienes. In detached leaves,
ultrastructure was also affected by dehydration, showing
damaged cells with altered chloroplasts which
retained large quantities of starch and lipid-like inclusions
in the stroma. Upon rehydration a continuous
degradation of the chemical composition and cell
organization was observed with a further increase in
peroxidation. Leaves dehydrated on the plant showed
degradation of chlorophyll and lipids, whereas carotenoids
increased and conjugated dienes decreased.
Desiccation caused a vacuolar fragmentation and a
decline in starch, whereas chloroplasts underwent
slight alterations. Following rewatering a full recovery
of chlorophyll and lipids occurred, while carotenoids
and dienes remained constant. Starch increased in the
chloroplasts and there was complete recovery of the
ordered cell arrangement and chloroplast organization..
Of the chloroplast polar lipids, in both sets of
leaves desiccation caused a reduction only in monogalactosyldiacylglycerol,
while phospholipids showed an
opposite pattern, increasing in air-dried leaves and
decreasing in detached leaves. Rewatering of leaves
desiccated on the plant led to a complete recovery of
the lipid composition, whereas detached leaves suffered
a complete lipid degradation with the loss of
polyunsaturated fatty acids
Protein dynamics in thylakoids of the desiccation-tolerant Boea hygroscopica during dehydration and rehydration
No full textEDDS-enhanced phytoextraction of metals from a multiple contaminated soil: effect of dose and time of application
No full textDifferential Expression of 1-Aminocyclopropane-1-carboxylate Synthase and Oxidase Gene Family in Micro-Tom Tomato Leaves and Roots Under Short Daily UV Radiation
No full textFew studies focussed on the effects of UV radiation on ethylene (ET) production, thus little is known about the changes in the expression of the ET biosynthetic genes and there are no data about roots. Based on our previous results showing reduced ET emission by UV-treated leaves of Micro-Tom tomato plants, the effects of short UV treatments (0.132 and 0.015 W m−2 biologically effective UV-B and UV-A irradiance, respectively, 15 min/day for 11 days) on the gene expression of the ET biosynthetic enzymes, ACC synthase (ACS1-7) and ACC oxidase (ACO1-5), were checked to determine whether UV radiation could cause changes at the transcriptional level and which isoforms were affected. The study regarded also roots to understand whether the invariance of root ET emission might relate to unchanged transcription of the biosynthetic genes or to a balance between up- and down-regulation of different isoforms. Chlorophylls and UV-responsive metabolites were quantified to verify plant healthiness and responsiveness. The general downregulation of ACO isoforms after 8 and 11 days of UV treatment was probably the cause of the reduced foliar ET emission, whilst after 3 days of recovery the similar ET levels agreed with the invariance of ACO transcript levels between control and treated plants. These data strengthen our hypothesis of ACOs as key ET regulators under short mild UV treatments, though, since we focussed on only 50% of the ACS genes, others may be involved in the tomato plant response to UV. Fluctuations of ACS and ACO mRNA were evident in roots, but this did not influence the ET emission of this organ
Short daily ultraviolet exposure enhances intrinsic water-use efficiency and delays senescence in Micro-Tom tomato plants
No full textUltraviolet (UV) radiation, unless present at high doses, is recognised as a regulator of plant growth and some specific processes. The present study investigated the influence of short daily UV irradiation (15 min/day, 11 days) on leaf gas exchange and some biochemical and molecular markers of leaf senescence (such as stomata movements, chlorophyll breakdown, anthocyanin production, senescence-associated genes) in Micro-Tom tomato plants. The UV-induced reduction of gs (stomatal conductance) during the treatment was associated with the modified expression of some genes involved in the control of stomatal movements. We hypothesise a two-step regulation of stomatal closure involving salicylic and abscisic acid hormones. The temporal changes of gs and Anet (net photosynthetic CO2 assimilation rate) along with the pigment behaviour, suggest a possible delay of leaf senescence in treated plants, confirmed by the expression levels of genes related to senescence such as SAG113 and DFR. The UV potential to induce a persistent partial inhibition of gs without severely affecting Anet led to an increased iWUE (intrinsic water-use efficiency) during the 11-day treatment, suggesting a priming effect of short daily UV radiation towards drought conditions potentially useful in reducing the excess water use in agriculture
Metal partitioning in plant-soil-water compartments under EDDS-assisted phytoextraction with Brassica carinata A. Braun.
No full textUltrastructure and plasmamembrane composition of resurrection plant Ramonda serbica Pan. and Petrov. (Gesneriaceae)
No full text
Influence of the Atmosphere Composition during Malaxation and Storage on the Shelf Life of an Unfiltered Extra Virgin Olive Oil: Preliminary Results
No full textThe nutraceutical and organoleptic quality of the extra virgin olive oil (EVOO) depends on a process that begins with the olive ripening and ends with the packaging and storage. As the EVOO quality decay is mainly induced by the oxidation process, the gaseous composition of the atmosphere during both malaxation and storage can play a key role. Because of that, the aim of this research work is to determine the influence of the gaseous composition of the atmosphere used during malaxation and storage on an unfiltered EVOO shelf life, and to individuate the best “malaxation atmosphere × storage atmosphere” combination to adopt to more effectively slow down the oil quality decay rate during storage. The combined experimental conditions used during malaxation and storage significantly affect the quality decay rate of the EVOO over one year of storage for all the evaluated parameters. In conclusion, the gaseous composition of the atmosphere used during both malaxation and storage deeply affects the shelf life of the unfiltered EVOO as regards its chemical and sensory features, especially when air is used. On the contrary, the best results are obtained when an inert gas (nitrogen or argon) is used during both phases. Practical Applications: The regular consumption of EVOO represents one of the main cornerstones of the Mediterranean diet. According to the FDA (Food and Drug Administration), this product can be considered as a healthy food because of its extraordinary nutraceutical and organoleptic properties, so that if consumers consume half a tablespoon of olive oil per day—without increasing their daily calorie intake—they can significantly reduce the incidence of several degenerative diseases as well as the risks associated with them. The knowledge of the impact of different “malaxation atmosphere × storage atmosphere” combinations on the quality decay rate during storage of an unfiltered EVOO can allow to identify the best operating conditions to be used during its production and storage, in order to preserve the nutraceutical and organoleptic properties of this product over time, thus extending its commercial life in terms of both quality parameters and healthy properties
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
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