1,721,493 research outputs found
Airborne signals and abiotic factors: the neglected side of the plant communication
Full text linkA relevant number of reports have examined the role of airborne signals in plant-plant communication, indicating that volatile organic compounds (VOCs) can prime neighboring plants against pathogen and/or herbivore attacks. Conversely, there is very limited information available on the possibility of the emission of VOCs by emitter plants under abiotic stress conditions, which may alert neighboring unstressed plants and prime these individuals (receivers) against the same stressors. The present opinion paper briefly reviews a few reports examining the effect of infochemicals produced by emitters on receiver plants subjected to abiotic stresses typical of global climate change. The ecological implications of these dynamics, as well as some concerns related to the potential roles of inter-plant communication in environmentally controlled experiments, have arisen. Some possible inter-plant communications applications (biomonitoring and biostimulation), mediated by airborne signals, and some directions for future studies on this topic, are also provided
Can anthocyanins be part of the metal homeostasis network in plant?
Full text linkAnthocyanins are a class of flavonoids with a high level of diversification and likely the most studied pathway of secondary metabolism in Plantae. Anthocyanins have raised a growing interest due to the huge variability of their chemical structures and the more new anthocyanins are isolated from plants, the more questions on their evolutionary and ecological meaning they raise. Antioxidant, photoprotection against high light and UV, defence against herbivores and pathogens, attraction of pollinator are only some proposed biological functions for those versatile compounds. Anthocyanins have also been found complexed with metal ions either in flower pigments (commelin and protocyanin) or in leaves and stems. Due to the potentiality of anthocyanins to chelate to metals, their involvement in the attenuation of metal toxicity has been recently proposed. Conversely, the ability of plants to remobilize metal ions from stored metal-anthocyanin complexes when plants experience a period of transient metal shortage has never been investigated before. The aim of this paper is to support the hypothesis that the anthocyanin-metal interactions might represent a further ecological role for these pigments and also that anthocyanins can be part of the complex network of metal homeostasis in plant
Commentary to: “Improving the thiobarbituric acid-reactive-substances assay for estimating lipid peroxidation in plant tissues containing anthocyanin and other interfering compounds” by Hodges et al., Planta (1999) 207:604–611
Full text linkHabitat characteristics and vegetation context of Osmunda regalis L. at the southern edge of its distribution in Europe
No full textThe abundance of Osmunda regalis was investigated in 42 natural populations in central Italy in order to (i) test which habitat characteristics correlate with its abundance at regional scale and at local scale, and (ii) identify the optimal habitats for the species in a Mediterranean area. This knowledge may contribute to the effective conservation of O. regalis, which is under threat in Italy. Ramets (rosettes of fronds) were counted in several plots of 25 m(2) within each population and related to habitat characteristics as well as plant species composition using univariate and multivariate statistics. The abundance of ramets at regional scale was positively correlated with mean annual precipitation and altitude. Large populations mainly occurred at sites with northeastern exposure, i.e. a cool and humid microclimate. The density of ramets at local scale was negatively correlated with rockiness, stoniness and shrub cover. Vascular plant species associated with high density of O. regalis were pioneer species typical of open woods and stagnant waters. Spring swamps therefore represent the habitat with the most favourable edaphic, microclimatic and vegetational conditions for the species at the southern edge of its distribution in Europe, where the limiting factor is the annual water availability
Osmundo-Alnion woods in Tuscany (Italy): A phytogeographical analysis from a west European perspective
No full textRiparian woods with
Alnus glutinosa
and
Osmunda regalis
in Tuscany (central Italy) were studied, whilst western European
riparian alderwoods were analysed from a phytogeographical perspective, with particular reference to
Osmundo–Alnion
and
its suballiances. Two associations were identified through the phytosociological analysis of the Tuscan coenoses:
Carici
pallescentis–Osmundetum regalis ass. nova
for mainland Tuscany and
Carici microcarpae–Alnetum glutinosae
for the Tuscan
islands. A phytogeographical analysis for western Europe (47 phytocoenoses, 567 relevés) was performed using floristic
classification and chorology-based discriminant analysis. These allowed us to identify phytocoenoses: (1) attributed to
Alnion incanae
, correlated with the Eurasian and Boreal chorotypes; and (2) attributed to
Osmundo–Alnion
, correlated with
the west Mediterranean, wide-distribution and Atlantic chorotypes. The floristic and ecological differences allowed us to
divide
Osmundo–Alnion
into two suballiances: (1) phytocoenoses distributed on the Iberian peninsula, correlated with the
Atlantic and endemic Iberian chorotypes, attributable to
Osmundo–Alnenion
; and (2) phytocoenoses distributed in Algeria,
Corsica, Sardinia, Sicily and Tyrrhenian Italy, correlated with the Mediterranean, endemic Sardinian–Corsican and
endemic Italian chorotypes, attributable to
Hyperico hircini–Alnenion glutinosae
The distribution of Osmunda regalis L. in Tuscany [Contributo alla conoscenza della distribuzione di Osmunda regalis L. in Toscana]
No full textThe results of bibliographic, herbarium and field studies relative to the distribution of Osmunda regalis are reported. The species is distributed in the west of the region in some principal groups (dispersal centres): at the base of the Alpi Apuane, in lower Arno Valley (Padule di Fucecchio-Monte Pisano- San Rossore), in Merse Valley, on Monte Leoni, in the Tuscan Archipelago (Elba and Giglio islands) and in the Argentario area. The distribution of the species is linked to springs swamps, water ways and marshes in a range between 0 and 600 m of altitude. New sites in southern Tuscany have been located through field research, and some old sites have been examined to verify the distribution of the species in recent years. The risk of its extinction in Tuscany is mainly due to degradation and reduction of habitat. Some information about the rarity of the species at a regional level is also provided. © 2018 Società Botanica Italiana onlus
Effects of abiotic stress on photosystem II proteins
No full textPhotosystem II (PSII) represents the most vulnerable component of the photosynthetic machinery and its response in plants subjected to abiotic stress has been widely studied over many years. PSII is a thylakoid membrane-located multiprotein pigment complex that catalyses the light-induced electron transfer from water to plastoquinone with the concomitant production of oxygen. PSII is rich in intrinsic (PsbA and PsbD, namely D1 and D2, CP47 or PsbB and CP43 or PsbC) but also extrinsic proteins. The first ones are more largely conserved from cyanobacteria to higher plants while the extrinsic proteins are different among species. It has been found that extrinsic proteins involved in oxygen evolution change dramatically the PSII efficiency and PSII repair systems. However, little information is available on the effects of abiotic stress on their function and structure
netmap: memory mapped access to network devices
No full textRecent papers have shown that wire-speed packet processing is feasible in software even at 10~Gbit/s, but the result has been achieved taking direct control of the network controllers to cut down OS and device driver overheads.
In this paper we show how to achieve similar performance in safer conditions on standard operating systems. As in some other proposals, our framework, called netmap, maps packet buffers into the process' memory space; but unlike other proposals, any operation that may affect the state of the hardware is filtered by the OS. This protects the system from crashes induced by misbehaving programs, and simplifies the use of the API.
Our tests show that netmap takes as little as 90 clock cycles to move one packet between the wire and the application, almost one order of magnitude less than using the standard OS path. A single core at 1.33~GHz can send or receive packets at wire speed on 10~Gbit/s links (14.8~Mpps), with very good scalability in the number of cores and clock speed.
At least three factors contribute to this performance: i) no overhead for encapsulation and metadata management; ii) no per-packet system calls and data copying (ioctl()s are still required, but involve no copying and their cost is amortized over a batch of packets); iii) much simpler device driver operation, because buffers have a plain and simple format that require
The vegetation gradient along the longitudinal profile of a braided stream: a case study in central Italy
No full textThe aim of this study was to evaluate the importance of the variation of environmental variables (geomorphological, topographical and climatic factors) along the lon gitudinal profile of a braided stream for the distribution of plant species and communities at a local scale. This was achieved by means of a case study in central Italy. Vegetation data from the river bed were grouped according to floristic and ecological affinities as follows: semi aquatic, helophytic, hygrophilous pioneer grasses, synantropical grasses, mesohygrophilous and pioneer grasses, garigues, hygrophilous shrubs, thermophilous shrubs, xerothermophilous shrubs and grasses, hygrophilous forest and thermophilous forest. A clear division between herbaceous and woody communities was observed along the first DCA axis and was inter preted as a transversal gradient of the stream due to decreasing flooding. Canonical Correspon dence Analysis suggested that altitude, distance from sea and bed width are the most important environmental variables explaining community distribution along the longitudinal profile. However, on this local scale, partial CCA showed that the abiotic variables explained 49.6% of the species data variation. This result, together with the lack of a correlation between environ mental factors and DCA axes 1 and 2, suggests that factors other than those included in the analysis, and probably only marginally linked to the longitudinal gradient, influenced the dis tribution of communities as well. On a local scale, we observed that there was no variation in the floristic composition of the coenoses along the longitudinal gradient. Consequently there is no vicariance of communities in terms of climate and/or biogeographic region. Along the longitudinal profile we found, however, the presence of coenoses that were ecologically (hard wood and soft wood) or structurally (dominance of woods, garigues, or pioneer coenoses) different in terms of geomorphological and topographical variables
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