scholarly journals Gelatinous fibers and variant secondary growth related to stem undulation and contraction in a monkey ladder vine,Bauhinia glabra(Fabaceae)

2014 ◽  
Vol 101 (4) ◽  
pp. 608-616 ◽  
Author(s):  
Jack B. Fisher ◽  
Mario A. Blanco
Keyword(s):  
Secondary Growth ◽  
Gelatinous Fibers

Anatomical and ultrastructural studies on gelatinous fibers in the organs of non-woody xerophytic and hydrophytic species

Botany ◽  
2019 ◽  
Vol 97 (10) ◽  
pp. 529-536 ◽  
Author(s):  
Tayeme Cristina Piva ◽  
Silvia Rodrigues Machado ◽  
Edna Scremin-Dias
Keyword(s):  
Secondary Growth ◽  
Woody Species ◽  
Distribution Patterns ◽  
Structural Features ◽  
Ultrastructural Studies ◽  
Gelatinous Fibers ◽  
Transmission Electron ◽  
Secondary Layer ◽  
Dry Soil ◽  
Electron Lucent

Gelatinous fibers (G-layer) occur widely in various organs and plant tissues of both primary and secondary origin, but they are best known in tension wood. Here, we describe the occurrence, distribution patterns, and structural features of G-fibers in non-woody species of xerophytes and hydrophytes in Brazilian Cerrado (dry soil) and Chaco (wet or periodically waterlogged soils). G-fibers were present in all of the studied species, but were more abundant and more developed in xerophytes. They were associated with the phloem of leaves and primary stems and with the xylem of three xerophytic species that exhibited incipient secondary growth. The G-layer was non-lignified and characterized by greater thickness, lower density, and loose appearance in relation to the secondary layers. Under a transmission electron microscope, G-fibers displayed two secondary parietal layers (S1 and S2) in Prosopis rubriflora Hassle. (xerophyte), three secondary layers (S1, S2, and S3) in Eriosema campestre Benth. var. campestre (xerophyte), and a single secondary layer (S1) in Ludwigia leptocarpa Nutt. (hydrophyte). In P. rubriflora, mature G-fibers exhibited a loose-appearing electron-lucent region (transition zone) between G- and S-layers (secondary layers). In addition to mechanical support, this study suggests the involvement of G-fibers in water storage.

ECCENTRIC GROWTH AND GROWTH STRESS IN INCLINED STEMS OF GNETUM GNEMON

IAWA Journal ◽  
2015 ◽  
Vol 36 (4) ◽  
pp. 365-377 ◽  
Author(s):  
Tatsuya Shirai ◽  
Hiroyuki Yamamoto ◽  
Masato Yoshida ◽  
Mikuri Inatsugu ◽  
Chisato Ko ◽  
...  
Keyword(s):  
Secondary Xylem ◽  
Secondary Growth ◽  
Microfibril Angle ◽  
Chemical Properties ◽  
Growth Stress ◽  
Reaction Wood ◽  
Wood Fibers ◽  
Gelatinous Fibers ◽  
Gnetum Gnemon ◽  
Negative Gravitropism

Gnetum gnemon L. (Gnetales) forms hardwood-like secondary xylem in its trunks and branches although it is a gymnosperm. The present study tested the surface growth stress in relation to anatomical and chemical properties of the secondary xylem in inclined and vertical stems of G. gnemon using morphological and chemical composition analyses. Secondary growth was promoted on the upper half of the cross section in an inclined stem; at the same time, tensile growth stress increased on the upper side and decreased on the lower side of the inclined stem. However, formation of reaction wood fibers was not detected on either side. The microfibril angle was associated with differences in tensile growth stress. Thus, we conclude that negative gravitropism in G. gnemon is caused by a synergistic effect of increased tensile growth stress as well as the promotion of secondary growth on the upper side of the inclined stem. Our results are comparable to the negative gravitropism observed in the family Magnoliaceae, which does not form gelatinous fibers in its tension wood.

Deposition time dependent study of structural and optical properties of PbS thin films grown by CBD method

2020 ◽  
Vol 13 ◽  
Author(s):  
Minakshi Chaudhary ◽  
Yogesh Hase ◽  
Ashwini Punde ◽  
Pratibha Shinde ◽  
Ashish Waghmare ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Band Gap ◽  
Deposition Time ◽  
Secondary Growth ◽  
Cost Effective ◽  
Xrd Analysis ◽  
Structural Morphology ◽  
Glass Substrates ◽  
Cbd Method

: Thin films of PbS were prepared onto glass substrates by using a simple and cost effective CBD method. Influence of deposition time on structural, morphology and optical properties have been investigated systematically. The XRD analysis revealed that PbS films are polycrystalline with preferred orientation in (200) direction. Enhancement in crystallinity and PbS crystallite size has been observed with increase in deposition time. Formation of single phase PbS thin films has been further confirmed by Raman spectroscopy. The surface morphology analysis revealed the formation of prismatic and pebble-like PbS particles and with increase in deposition time these PbS particles are separated from each other without secondary growth. The data obtained from the EDX spectra shows the formation of high-quality but slightly sulfur rich PbS thin films over the entire range of deposition time studied. All films show increase in absorption with increase in deposition time and a strong absorption in the visible and sub-band gap regime of NIR range of the spectrum with red shift in band edge. The optical band gap shows decreasing trend, as deposition time increases but it is higher than the band gap of bulk PbS.

Hymenachne acutigluma (Steud.) Gilliland in GBS 20:314 - An exceptionally important perennial grass for anatomy and indigenous practice.

2016 ◽  
Vol 5 (04) ◽  
pp. 4958
Author(s):  
Dulal De
Keyword(s):  
Perennial Grass ◽  
Secondary Growth ◽  
Grass Species ◽  
Stem Anatomy

Hymenachne acutigluma (Steud.) Gilliland, a robust rhizomatous perennial grass spreads on moist and swampy land and also floating in water. Being a grass species, they do not have any cambium for secondary growth. A peculiarity in stem anatomy especially the spongy pith of secondary tissues found in absence of the cambium. The origin and development of the parenchymatous pith tissues has been investigated in the present study. Economically this spongy pith is of very much potent for its high absorbing and filtering capacity and also used as a good fodder.

Living on the edge: legacy of water availability on Tetraclinis articulata secondary growth under semiarid conditions in Morocco

2021 ◽  
pp. 125853
Author(s):  
Vicente Rozas ◽  
Ana I. García-Cervigón ◽  
Miguel García-Hidalgo ◽  
Erik Rodríguez-García ◽  
José M. Olano
Keyword(s):  
Water Availability ◽  
Secondary Growth ◽  
Tetraclinis Articulata ◽  
Semiarid Conditions

scholarly journals Relevance of processing parameters for grain growth of metal halide perovskites with nanoimprint

2021 ◽  
Vol 127 (9) ◽  
Author(s):  
Andre Mayer ◽  
Tobias Haeger ◽  
Manuel Runkel ◽  
Johannes Rond ◽  
Johannes Staabs ◽  
...  
Keyword(s):  
Grain Size ◽  
Grain Growth ◽  
Secondary Growth ◽  
Processing Parameters ◽  
Post Processing ◽  
Perovskite Layer ◽  
Processing Step ◽  
Similar Preparation ◽  
Materials Used ◽  
Log Normal

AbstractThe quality and the stability of devices prepared from polycrystalline layers of organic–inorganic perovskites highly depend on the grain sizes prevailing. Tuning of the grain size is either done during layer preparation or in a post-processing step. Our investigation refers to thermal imprint as the post-processing step to induce grain growth in perovskite layers, offering the additional benefit of providing a flat surface for multi-layer devices. The material studied is MAPbBr3; we investigate grain growth at a pressure of 100 bar and temperatures of up to 150 °C, a temperature range where the pressurized stamp is beneficial to avoid thermal degradation. Grain coarsening develops in a self-similar way, featuring a log-normal grain size distribution; categories like ‘normal’ or ‘secondary’ growth are less applicable as the layers feature a preferential orientation already before imprint-induced grain growth. The experiments are simulated with a capillary-based growth law; the respective parameters are determined experimentally, with an activation energy of Q ≈ 0.3 eV. It turns out that with imprint as well the main parameter relevant to grain growth is temperature; to induce grain growth in MAPbBr3 within a reasonable processing time a temperature of 120 °C and beyond is advised. An analysis of the mechanical situation during imprint indicates a dominance of thermal stress. The minimization of elastic energy and surface energy together favours the development of grains with (100)-orientation in MaPbBr3 layers. Furthermore, the experiments indicate that the purity of the materials used for layer preparation is a major factor to achieve large grains; however, a diligent and always similar preparation of the layer is equally important as it defines the pureness of the resulting perovskite layer, intimately connected with its capability to grow. The results are not only of interest to assess the potential of a layer with respect to grain growth when specific temperatures and times are chosen; they also help to rate the long-term stability of a layer under temperature loading, e.g. during the operation of a device.

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