Non-structural carbohydrates (NSCs), the stored products of photosynthesis, building blocks for growth and fuel for respiration, are central to plant metabolism, but their measurement is challenging. Differences in methods and procedures among laboratories can cause results to vary widely, limiting our ability to integrate and generalize patterns in plant carbon balance among studies. A recent assessment found that NSC concentrations measured for a common set of samples can vary by an order of magnitude,...
6h
The extent to which plants can reduce nutrient concentrations in soil and thereby compete with others may increase with nutrient mobility. Hyphae of arbuscular mycorrhizal fungi (AMF) can extend the soil volume from which plants acquire phosphorus (P), thus increasing competition for these resources with neighbours. In this study, we tested whether the suppression of hyphal interconnections between neighbour plants mitigates their competitive interactions and consequently affects plant community...
6h
Soil respiration plays a crucial role in global carbon cycling. While the response of soil respiration to abiotic drivers like soil temperature and moisture is fairly well understood, less is known about the effects of biotic drivers, such as plant above- and belowground productivity or plant diversity, and their interactions with abiotic drivers on soil respiration. Thus, current predictions of soil respiration to summer droughts might miss relevant biological drivers and their interactions with...
6h
Legume-cereal intercropping is well known in traditional dry land agriculture. Here, we tested whether finger millet, a shallow-rooted cereal, can profit from neighboring pigeon pea, a deep-rooted legume, in the presence of "biofertilization" with arbuscular mycorrhizal fungi (AMF) and plant growth-promoting rhizobacteria (PGPR), under drought conditions. We conducted a greenhouse experiment using compartmented microcosms. Pigeon pea was grown in a deep compartment with access to a moist substrate...
6h
We used four years of sap flow measurements to elucidate intra- and inter-specific variability of gs in Larix decidua Mill. and Picea abies (L.) Karst along an elevational gradient and contrasting soil moisture conditions. Site- and species-specific gs response to main environmental drivers were examined, including vapour pressure deficit, air temperature, solar irradiance and soil water potential. Our results indicate that maximum gs of L. decidua is >2 times higher, shows a more plastic response...
6h
Climate change is particularly apparent in many mountainous regions, with warming rates of more than twice the global average being reported for the European Alps. As a result, the probability of climate extremes has increased and is expected to rise further. In an earlier study, we looked into immediate impacts of experimentally imposed heat waves in alpine grassland, and found that these systems were able to cope with heat as long as enough water was available. However, concomitant drought led...
6h
Alpine ecosystems are, similar to arctic ecosystems, characterized by a very long snow season. Previous studies investigating arctic or alpine ecosystems have shown that winter CO2 effluxes can dominate the annual balance and that the timing and duration of the snow cover plays a crucial role for plant growth and phenology and might also influence the growing season ecosystem CO2 strength and dynamics. The objective of this study was to analyze seasonal and annual CO2 balances of a grassland site...
6h
Compound specific hydrogen isotope ratios (H-2/H-1) of lipid biomarkers preserved in sediments are used as paleohydrologic proxies. However, several variables, including contributions from different source organisms and their growth rates, can influence H-2/H-1 fractionation between lipids and source water. Significant uncertainties remain about how these factors combine to produce the net H-2/H-1 signal exported to sediments.To assess the influence of phosphorus availability on H-2/H-1 ratios of...
6h
Drought is a major environmental constraint to trees, causing severe stress and thus adversely affecting their functional integrity. European beech (Fagus sylvatica L.) is a key species in mesic forests that is commonly expected to suffer in a future climate with more intense and frequent droughts. Here, we assessed the seasonal response of leaf physiological characteristics of beech saplings to drought and drought release to investigate their potential to recover from the imposed stress and overcome...
6h
Climate change can adversely affect the growth of European beech (Fagus sylvatica L.) across its entire distribution range. Therefore, knowledge of the adaptive potential of this species to changing climatic conditions is of foremost importance. Genetic diversity is the basis for adaptation to environmental stress, and the regeneration phase of forests is a key stage affecting genetic diversity. Nevertheless, little is known about the effect of climate change on the genetic diversity of adult trees...
6h
Adaptive phenotypic plasticity and fixed genotypic differences have long been considered opposing strategies in adaptation. More recently, these mechanisms have been proposed to act complementarily and under certain conditions jointly facilitate evolution, speciation, and even adaptive radiations. Here, we investigate the relative contributions of adaptive phenotypic plasticity; vs; . local adaptation to fitness, using an emerging model system to study early phases of adaptive divergence, the generalist...
6h
Owing to their taxonomic, phenotypic, ecological and behavioural diversity and propensity for explosive diversification, the assemblages of cichlid fish in the East African Great Lakes Victoria, Malawi and Tanganyika are important role models in evolutionary biology. With the release of five reference genomes and many additional genomic resources, as well as the establishment of functional genomic tools, the cichlid system has fully entered the genomic era. The in-depth genomic exploration of the...
6h
Random asymmetry, that is the coexistence of left- and right-sided (or -handed) individuals within a population, is a particular case of natural variation; what triggers and maintains such dimorphisms remains unknown in most cases. Here, we report a field-based cage experiment in the scale-eating Tanganyikan cichlid Perissodus microlepis, which occurs in two morphs in nature: left-skewed and right-skewed individuals with respect to mouth orientation. Using underwater cages stocked with scale-eaters...
6h
Astatotilapia burtoni is a member of the "modern haplochromines," the most species-rich lineage within the family of cichlid fishes. Although the species has been in use as research model in various fields of research since almost seven decades, including developmental biology, neurobiology, genetics and genomics, and behavioral biology, little is known about its spatial distribution and phylogeography. Here, we examine the population structure and phylogeographic history of; A. burtoni; throughout...
6h
[This corrects the article DOI: 10.1371/journal.pone.0189278.].
6h
The world's smallest fishes belong to the genus Paedocypris. These miniature fishes are endemic to an extreme habitat: the peat swamp forests in Southeast Asia, characterized by highly acidic blackwater. This threatened habitat is home to a large array of fishes, including a number of miniaturized but also developmentally truncated species. Especially the genus Paedocypris is characterized by profound, organism-wide developmental truncation, resulting in sexually mature individuals of <8 mm in...
6h
Adaptive radiations, in which repeated bouts of diversification lead to phenotypically similar species, highlight the power of natural selection and predictability in evolution. A newly discovered radiation of stick spiders on Hawaii helps shed new light on this phenomenon.
6h
Morphological convergence triggered by trophic adaptations is a common pattern in adaptive radiations. The study of shape variation in an evolutionary context is usually restricted to well-studied fish models. We take advantage of the recently revised systematics of New World Ariidae and investigate skull shape evolution in six genera of northern Neotropical Ariidae. They constitute a lineage that diversified in the marine habitat but repeatedly adapted to freshwater habitats. 3D geometric morphometrics...
6h
The closure of the Isthmus of Panama has long been considered to be one of the best defined biogeographic calibration points for molecular divergence-time estimation. However, geological and biological evidence has recently cast doubt on the presumed timing of the initial isthmus closure around 3 Ma but has instead suggested the existence of temporary land bridges as early as the Middle or Late Miocene. The biological evidence supporting these earlier land bridges was based either on only few molecular...
6h
Sexual dimorphism is founded upon a resource allocation trade-off between investments in reproduction versus other life-history traits including the immune system. In species with conventional parental care roles, theory predicts that males maximize their lifetime reproductive success by allocating resources toward sexual selection, while females achieve this through prolonging their lifespan. Here, we examine the interrelation between sexual dimorphism and parental care strategies in closely related...
6h
Tumor cells display features that are not found in healthy cells. How they become immortal and how their specific features can be exploited to combat tumorigenesis are key questions in tumor biology. Here we describe the long non-coding RNA cherub that is critically required for the development of brain tumors in; Drosophila; but is dispensable for normal development. In mitotic; Drosophila; neural stem cells, cherub localizes to the cell periphery and segregates into the differentiating daughter...
7h
The acoel worm Symsagittifera roscoffensis, an early offshoot of the Bilateria and the only well-studied marine acoel that lives in a photosymbiotic relationship, exhibits a centralized nervous system, brain regeneration, and a wide repertoire of complex behaviors such as circatidal rhythmicity, photo/geotaxis, and social interactions. While this animal can be collected by the thousands and is studied historically, significant progress is made over the last decade to develop it as an emerging marine...
7h
Computational methods, namely Molecular Dynamics Simulations (MD simulations) in combination with Inhomogeneous Fluid Solvation Theory (IFST) were used to retrospectively investigate various cases of ligand structure modifications that led to the displacement of binding site water molecules. Our findings are that the water displacement per se is energetically unfavorable in the discussed examples, and that it is merely the fine balance between change in protein-ligand interaction energy, ligand solvation...
7h
9h
Mixing solutions of homoleptic cobalt(II) complexes [CoA(2)](2+) and [CoB2](2+) results in the establishment of a combinatorial library containing the heteroleptic complex [CoAB](2+) By using enantiomorphic ligands A and B the reactions may be followed by H-1 NMR spectroscopy. Exchange reactions with 6-substituted ligands are slower than those with 5- and 4-substituted species.
15h
Self-assembled monolayers of [Ru(terpy)(terpy-py)](2+) and [Os(terpy)(terpy-py)](2+) salts (terpy is 2,2`:6`,2``-terpyridine and terpy-py is 4`-(4-pyridyl)-2,2`:6`,2``-terpyridine) on platinum were investigated by means of STM and electrochemistry. The STM experiments reveal that the species within the monolayer are ordered in a hexagonal array. This information was utilized together with the scan rate dependency of the peak current density (j(p)) of potential sweep experiments to calculate interaction...
15h
The structure of 3,5-dimethoxybenzyl alcohol has been determined directly from powder X-ray diffraction data using the genetic algorithm technique for structure solution followed by Rietveld refinement. This material is the precursor to a family of dendrimer materials, and structural features exhibited by 3,5-dimethoxybenzyl alcohol in the solid state may be important in the rationalization of higher generation dendrimer materials within this family.
15h
The electronic absorption spectra, luminescence spectra and lifetimes (in MeCN at room temperature and in frozen n-C3H7CN at 77K). and electrochemical potentials (in MeCN) of the novel dinuclear [(tpy)Ru(3)Os(tpy)](4+) and trinuclear [(tpy)Ru(3)Os(3)Ru(tpy)](6+) complexes (3=2,5-bis(2,2`:6`,2``-terpyridin-4-yl)thiophene) have been obtained and are compared with those of model mononuclear complexes and homometallic [(tpy)Ru(3)Ru(tpy)](4+), [(tpy)Os(3)Os(tpy)](4+) and [(tpy)Ru(3)Ru(3)Ru(tpy)](6+) complexes....
15h
Algorithms used for the assembly of metallosupramolecular constructs are simple and based upon well-established principles of coordination chemistry. The multinucleating ligand 3,6-bis(2-pyridyl)pyridazine forms a [2 x 2] grid with copper(l); the related ligand 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine (dptz) is expected to behave in a similar manner with silver(l). However, instead of the expected grid, [Ag(dptz)(2)](+) Solution species are formed. In the solid state, dinuclear [Ag-2(dPtZ)(2)](2+) and...
15h
The complex [(bipy)(2)Ru(dpp)][PF6](2) which contains a vacant 2,2`-bipyridine-like metal-binding domain has been structurally characterised. This compound is a key building block for the construction of metallodendrimers using the ``complexes as metals, complexes as ligands`` approach. (C) 2001 Elsevier Science B.V. All rights reserved.
15h
The reaction of 4`-phenyl-2,2`:6`, 2``-terpyridine I with nickel(II) chloride gives a 1: 1 adduct which we have structurally characterised and shown to be comprised of two species of stoichiometry Ni(I)Cl-2; the first is a five-coordinate [Ni(I)Cl-2] complex and the other is a dinuclear species containing two six-coordinate nickel centres [(I)ClNi(mu-Cl)(2)Ni(I)Cl]. (C) 2002 Elsevier Science B.V. All rights reserved.
15h
The evaporation of solutions of dendron-functionalised 2,2`-bipyridines on a graphite surface gives highly ordered monolayers; near atomic resolution STM imaging has allowed a detailed conformational analysis to be made.
16h
Reaction of the heterotritopic ligand L, which contains one bipy and two terpy metal-binding domains linked by a flexible spacer with iron(II) chloride results in the formation of a [1 + 1] metallomacrocycle.
16h
The Bell-Evans-Polanyi principle that is valid for a chemical reaction that proceeds along the reaction coordinate over the transition state is extended to molecular dynamics trajectories that in general do not cross the dividing surface between the initial and the final local minima at the exact transition state. Our molecular dynamics Bell-Evans-Polanyi principle states that low energy molecular dynamics trajectories are more likely to cross into the basin of attraction of a low energy local minimum...
16h
Intermetallic compounds made of alkali metals and gold have intriguing electronic and structural properties that have not been extensively explored. We perform a systematic study of the phase diagram of one binary system belonging to this family, namely NaxAu1-x, using the ab initio minima hopping structural prediction method. We discover that the most stable composition is NaAu2, in agreement with available experimental data. We also confirm the crystal structures of NaAu2 and Na2Au, that were fully...
16h
Density functional calculations have been carried out to obtain low energy equilibrium geometries of anionic and neutral sodium clusters over a wide range of sizes 40 <= N 41. The agreement between theory and experiment is good for almost all the clusters and the changes in the spectrum with size correlate very well with the changes in the shapes as observed in the evolutionary trend of the ground state geometries.
16h
A novel allotrope of carbon with P2/m symmetry was identified during an ab initio minima-hopping structural search which we call M10-carbon. This structure is predicted to be more stable than graphite at pressures above 14.4 GPa and consists purely of sp(3) bonds. It has a high bulk modulus and is almost as hard as diamond. A comparison of the simulated X-ray diffraction pattern shows a good agreement with experimental results from cold compressed graphite.
Δεν υπάρχουν σχόλια:
Δημοσίευση σχολίου