Tree-like Growth Research Articles

Variation in Results of Three Biology‐Focused Search Engines: A Case Study Using North American Tree Species

Variation in Results of Three Biology‐Focused Search Engines: A Case Study Using North American Tree Species

Plant Trait Dataset for Tree-Like Growth Forms Species of the Subtropical Atlantic Rain Forest in Brazil

Plant functional traits have been incorporated in studies of vegetation ecology to better understand the mechanisms of ecological processes. For this reason, a global effort has been made to collect functional traits data for as many species as possible. In light of this, we identified the most common species of an area of 15,335 km2 inserted in the subtropical Atlantic Rain Forest in Southern Brazil. Then, we compiled functional trait information mostly from field samples, but also from herbarium and literature. The dataset presents traits of leaf, branch, maximum potential height, seed mass, and dispersion syndrome of 117 species, including trees, tree ferns, and palms. We also share images of anatomical features of branches used to measure wood traits. Data tables present mean trait values at individual and species level. Images of wood and stomatal features may be useful to assess other anatomical traits that were not covered in the data tables for the anatomical determination of species and/or for educational purposes.

Atypical origin, structure and arrangement of secondary tracheary elements in the stem of the monocotyledonous dragon tree, Dracaena draco

Main conclusionTracheary elements within the secondary body of a dragon tree shared features characteristic of fibres. Their considerable intrusive growth resulted in a rigid network with a braid-like arrangement which contributes towards the tree-like form of the plant.Monocot cambium gives rise to xylem and phloem which become organized into vascular bundles. The xylem consists entirely of tracheids, and these undergo considerable intrusive elongation during their development, unlike the tracheids of conifers and those of vesselless dicotyledons. Monocot tracheids have not been fully investigated, and our understanding of their structure is incomplete. Therefore, in this study the degree of variation in the structure and arrangement of secondary tracheary elements of monocots were determined, based on the Dracaena draco stem. In addition, its mechanical and physiological implications were discussed. Analysis of series of thin serial sections and macerations of the immature and fully developed tracheids showed that the course of intrusive elongation of tracheids was determined by the spatial relationship that exists between the growing tracheid and surrounding cells, and was not usually parallel to the stem axis. It influenced the shape of tracheids, as well the cross-sectional shape of vascular bundles. Tracheids become twisted or even interwoven and so, their ends do not join with the ends of other tracheids. The complexity of the tracheid network, that functions both in transport and mechanical support, seems to have a major impact on the tree-like growth habit of D. draco.

Dendritic Peptide Nanostructures Formed from Self-Assembly of Di-l-phenylalanine Extracted from Alzheimer’s β-Amyloid Poly Peptides: Insights into Their Assembly Process

This paper presents formation of a new class of dendritic peptide nanostructures from self-assembly of diphenylalanine extracted from Alzheimer’s β-amyloid polypeptide. Effects of different substrates e.g. glass, silicon and gold on morphology of dendritic nanostructures have been studied by means of AFM and FESEM. Furthermore, formation of self-assembled structures in solution has been characterized in terms of dimensions of nanotubes via Zetasizer. The results showed formation of highly ordered dendritic multi-branched structures spread on glass in which diameter of each tubular structure varies from 200 to 800 nm. Silicon substrates promoted aggregation with less dendrite characteristics. Individual nanotubes were formed on gold solid substrates. The growth of nucleation points was accelerated via spin casting. In solution, however, the diameter size showed an average of 296 nm after 1 day of self-assembly. A mechanism is proposed to explain tree-like growth of FF dendritic nanostructures. Our approach offers a biomaterial which proves highly useful for a broad range of application from drug delivery to nanofabrication techniques.

Earthworm invasions and the decline of clubmosses (Lycopodium spp.) that enhance nest survival rates of a ground-nesting songbird

Invasive earthworms have numerous adverse effects on soils, plants, and vertebrates in forests of North America. Relatively little research has linked earthworm invasions to population vital rates of vertebrates while also assessing habitat characteristics that drive these responses. Furthermore, most investigations of earthworm impacts on plants have focused on graminaceous, woody, and herbaceous species. At sites representing different stages of earthworm invasion, we studied a group of fern-like plants, the clubmosses (Lycopodium spp.), that may be adversely affected by invasions of Lumbricus spp. earthworms, are harvested by humans, and are commonly used by ground-nesting songbirds as a nesting substrate. We found a strong inverse association between Lumbricus biomass and the presence of two clubmoss groups, those with a tree-like growth form (i.e., “tree clubmosses”) and those with a finger-like growth form (i.e., “common clubmosses”). Despite finding no relationship between clubmoss presence and visual concealment of nests, we provide evidence that two ground-nesting songbirds, the Ovenbird (Seiurus aurocapilla) and Hermit Thrush (Catharus guttatus), preferentially place their nests near tree clubmosses and that the presence of tree clubmosses increases Ovenbird nest survival probability by 32% on average. Although ecological mechanisms for the relationships between Lumbricus invasions and clubmosses and between tree clubmosses and Ovenbird nest survival are unclear, our findings provide additional motivation to manage forest ecosystems against earthworm invasions. In addition, we highlight the need to manage the human harvest of clubmosses to promote sustainability of clubmoss populations that are simultaneously threatened by earthworms and harvest and to minimize adverse impacts on songbirds.

Massive aerial roots affect growth and form of Dracaena draco

Large aerial roots grow out from the branches of injured Dracaena draco trees. They integrate with the trunk or cause the branches to break off the tree and deform it. Dracaena draco, the dragon tree, is an iconic monocot of the Canary Islands with a tree-like growth habit and some distinctive features that are unique in the plant kingdom. We report about the massive aerial roots in this tree. They appear on trees that are injured or under environmental stress and affect growth form and the whole life of the plant. We analysed the growth of these roots and tested our findings in experiments on plants. Clusters of these roots emerge from the bases of the lowest branches and growing down they may reach the soil. Descending along the trunk, they cling tightly to the trunk, integrate with it and contribute to its radial growth. This may explain (1) why the trunk of a mature D. draco tree looks fibrous, as if made of many individual strands, and (2) how some trees reach enormous radial dimensions. Alternately, a large, 2–5 m high, multi-segmented branch with aerial roots at its base, may break off the tree and grow on its own, as a mammoth off-cut, perhaps the largest known in the plant kingdom. This detachment would cause a significant reduction in the size of the crown and deform its original, highly organized pattern of branching. In the extreme condition this may result in the destruction of the mother plant.

Synthesis of Platelet Carbon Nanofiber/Carbon Felt Composite on in Situ Generated Ni−Cu Nanoparticles

A platelet carbon nanofiber/carbon felt composite with a high surface area (>250 m2/g) is synthesized over a carbon felt supported Ni−Cu catalyst using ethane−hydrogen mixtures at 923 K. A uniform layer of carbon nanofibers is thus achieved via an in situ generation and dispersion of Ni−Cu nanoparticles induced by the surface reaction of hydrocarbon decomposition. This represents a cost-effective and flexible method without the requirement for presynthesis of uniformly distributed nanoparticles. Both thermodynamic analysis and experimental observation reveal that, in the initial growth period, formation of a molten phase of the nanosized Ni−Cu−C phase promotes the fragmentation of Ni−Cu parent particles of micrometer size. A unique octopus-like growth mode is observed during the formation of graphene layers from this liquid-like Ni−Cu−C system. A comparative study between Ni and Ni−Cu catalysts is performed. It is found that the addition of Cu in the Ni−Cu catalysts can enhance the fragmentation ability of the parent Ni−Cu particles when contacting with hydrocarbon. A treelike growth mode of carbon nanofibers grown on Ni−Cu catalysts is observed due to the further fragmentation of Ni−Cu particles during carbon nanofiber growth. In contrast to Ni−Cu catalysts, two different growth mechanisms on the Ni catalyst are found: a governing tip-growth mechanism by particles smaller than 50 nm and an octopus-like growth mechanism by larger particles (50−100 nm). The graphene sheet orientation in the carbon nanofibers depends on the composition of the metal particle; fishbone carbon nanofibers are obtained with carbon felt supported Ni catalysts, while platelet carbon nanofibers were obtained with Ni−Cu catalysts. The formation of platelet carbon nanofibers from the Ni−Cu catalysts is ascribed to a higher degree of interface wetting between the Ni−Cu particle and the produced graphene sheets.

Surface morphology of {100} faces ofL-arginine phosphate monohydrate single crystals investigated by atomic force microscopy

Surface morphology of {100} faces of LAP crystals was investigated by atomic force microscopy (AFM). Both the steps and the two-dimensional nuclei elongate along thebdirection, which is determined by the crystal structure. Fluctuations in the growth conditions could result in the formation of protuberances on the step fronts. Tree-like growth belts are initially observed on LAP crystals. It is assumed that the formation is caused by uneven liquid flow of the mother solution.

Growth and Reproduction of the InvasiveLigustrum sinenseand NativeForestiera ligustrina(Oleaceae): Implications for the Invasion and Persistence of a Nonnative Shrub

Ligustrum sinense (Oleaceae) is an invasive shrub in the southeastern United States that was introduced from China. In middle Tennessee, the species grows with Forestiera ligustrina (Oleaceae), a shrub native to the southeastern United States, in the redcedar and/or hardwood forests surrounding cedar (limestone) glades. Here we compare the growth and reproduction of the two species and identify attributes that might influence the invasiveness and persistence of L. sinense. Plants of both species were sampled along the woodland edges of cedar glades and in the (primarily) redcedar forest at Stones River National Battlefield, Rutherford County, Tennessee, between March 2000 and February 2001. MANOVAs ($$P\leq 0.05$$) indicated significant differences between species and habitats for several of the 23 traits measured in the study. Regardless of the habitat, L. sinense had a more treelike growth form—higher leaf area ratio (leafiness), leaf mass ratio (investment in leaf biomass), stem elongation rate, and number of fruits per ramet—and a lower percentage of insect‐damaged leaves and leaf abscission rate than F. ligustrina. Height and leaf areas of L. sinense plants growing in the woods were greater than those of L. sinense plants growing along the glade and greater than those of F. ligustrina plants growing in both habitats. Branch architecture did not differ appreciably between the species. Ligustrum sinense appears to possess a competitive advantage over F. ligustrina because of its greater ability to spatially and temporally capture light, a phenomenon that may lead to higher photosynthetic capacity and resource‐use efficiency, and because of the higher fruit production we observed.

電解重合法によるポリピロールのトリー状成長とフラクタル解析

電解重合法によるポリピロールのトリー状成長とフラクタル解析

Silver Migration in Glass Dams between Silver-Palladium Interconnections

It is shown that two mechanisms are encountered in metal migration in glass-a platelike and treelike growth mechanism. The treelike growth, requiring a much higher interfacial energy contribution, is favored by high voltage application. The interaction of these two mechanisms accounts for the unexpected voltage and gap dependence of the niigration rate. The location of the metallic growth has been established as being in the volume of the glass. Significant differences exist in the electrical characteristics of the substrates of different manufacturers. After the application of glass dams these differences become less pronounced.

Montmorillonite Dendrites

Morphological features of montmorillonite aggregates in a large number of samples suggest that they may be formed by a dendritic crystal growth mechanism (i.e., tree-like growth by branching of a growth front).