The leaf anatomy of hemlock, Tsuga canadensis

1974 ◽  
Vol 52 (5) ◽  
pp. 1049-1056 ◽  
Author(s):  
R. L. Gambles ◽  
N. G. Dengler
Keyword(s):  
Cell Walls ◽  
Water Movement ◽  
Mesophyll Cell ◽  
Tsuga Canadensis ◽  
Structural Features ◽  
Intercellular Spaces ◽  
Spongy Mesophyll ◽  
Surface Areas ◽  
Average Maximum ◽  
Leaf Volume

Structural features related to the pathway of water movement in the leaf of hemlock, Tsuga canadensis (L.) Carr., have been examined in conjunction with investigations of plant water relations. Cell surface areas and volumes were determined by projecting 2-μm serial sections, measuring them with a map tracer, and multiplying cell perimeters by section thickness; or by the trace–cut–weigh method. Scanning electron microscope observations showed that the stomata are occluded with a continuous layer of rod-like wax particles. The average maximum distance over which water must move from the xylem of the single median bundle to the mesophyll is 770 μm, and each 40 μm of length of vein (the diameter of a mesophyll cell) supplies 196 cells. The palisade mesophyll consists of two layers, while the spongy mesophyll is arranged in sheets which radiate from the vascular bundle to the margin and alternate with large intercellular spaces. The mesophyll cell walls may provide the pathway through which the bulk of the water moves; the volume occupied by the mesophyll cell walls is 1.27 × 10−4 cm3 or 2.5% of total leaf volume. The total evaporative surface area of the mesophyll is 1.61 cm2 per leaf.

Mesophyll cell walls in hemlock, Tsuga canadensis

1977 ◽  
Vol 55 (11) ◽  
pp. 1510-1515
Author(s):  
R. Fischer ◽  
N. G. Dengler
Keyword(s):  
Cell Surface ◽  
Cell Walls ◽  
Mesophyll Cell ◽  
Tsuga Canadensis ◽  
Structural Features ◽  
Ruthenium Red ◽  
Intercellular Spaces ◽  
Mesophyll Cells ◽  
Thin Sections ◽  
Histochemical Tests

Observations have been made on the walls of the mesophyll cells in the leaves of hemlock, Tsuga canadensis, to determine if there were any structural features which would account for the relatively high resistance measured at the mesophyll cell surface in infiltrated leaves by Tyree et al. (1975). There was no indication of an internal cuticle based on histochemical tests of fresh sections and the appearance of the wall in electron micrographs. Examination of Alcian-blue-stained fresh sections and thin sections of material treated with ruthenium red indicated that mesophyl) cell walls may be covered with a mucilaginous layer that retards the evaporation of water to intercellular spaces.

The leaf anatomy of beech, Fagus grandifolia

1975 ◽  
Vol 53 (19) ◽  
pp. 2202-2211 ◽  
Author(s):  
Nancy G. Dengler ◽  
Lynette B. MacKay
Keyword(s):  
Surface Area ◽  
Cell Walls ◽  
Vascular Tissue ◽  
Leaf Surface ◽  
Mesophyll Cell ◽  
Fagus Grandifolia ◽  
Mesophyll Cells ◽  
Surface Areas ◽  
Leaf Surface Area ◽  
Leaf Volume

Observations have been made on the anatomy of beech, Fagus grandifolia Ehrh., with an emphasis on quantitative features. All surface areas and volumes were determined by projecting 2-μm serial sections, measuring them with a map tracer, and multiplying cell perimeters by section thickness or by the trace–cut–weight method. The organization of tissues, including a complex reticulate venation, is typical of many dicotyledons. Of the minor veins, only the quinternaries and veinlets lack bundle sheath extensions and have wholly parenchymatous bundle sheaths, the cells of which are often oriented at right angles to the vein. There are 12.1 mm of vein per square millimetre of leaf surface area, and 10 μm of vein (the diameter of a mesophyll cell) serves about 21.5 mesophyll cells. The mean maximum distance over which water and solutes must move between vascular tissue and mesophyll is 55 μm. The mesophyll cell walls may provide the pathway through which the bulk of the water moves; the volume occupied by the mesophyll cell walls is 55.7 mm3 or 11% of total leaf volume. The evaporative surface of the mesophyll is 13.36 mm2/mm2 leaf surface area.

Morphological peculiarities of seeds of some species of the genus Epipactis Zinn. (Orchidaceae Juss.) of Ukrainian flora

2019 ◽  
Vol 11 (1) ◽  
pp. 93-100
Author(s):  
T Ljubka ◽  
O Tsarenko ◽  
I Tymchenko
Keyword(s):  
Seed Coat ◽  
Cell Walls ◽  
Morphological Study ◽  
Population Level ◽  
Intercellular Spaces ◽  
Different Populations ◽  
Periclinal Walls ◽  
High Degree ◽  
Shape And Size ◽  
Generative Organs

The investigation of macro- and micromorphological peculiarities of seeds of four species of genus Epipactis (Orchidaceae) of Ukrainian flora were carried out. The genus Epipactis is difficult in the in in taxonomic terms and for its representatives are characterized by polymorphism of morphological features of vegetative and generative organs of plants and ability of species to hybridize. The aim of the research was to perform a comparative morphological study of seeds of E. helleborine, E. albensis, E. palustris, E. purpurata and to determine carpological features that could more accurately identify species at the stage of fruiting. A high degree of variation in the shape of the seeds in different populations within the species and overlap of most quantitative carpological characteristics of studied species are noted. There were no significant differences in micromorphological features of the structure of the testa at species or population level. The reticulate surface of the testa is characteristic of all species, the cells of testa are mostly elongated, penta-hexagonal, individual cells almost isodiametric-pentagonal. From the micropillary to the chalasal end, a noticeable change in the shape and size of the seed coat cells is not observed. There are no intercellular spaces, the anticlinal walls of adjacent cells are intergrown and the boundaries between them become invisible. The outer periclinal walls have a single, mainly longitudinal thin ribbed thickenings. Anticlinal cell walls are thick, dense, smooth. The longitudinal Anticlinal walls are almost straight, transverse - straight or sometimes curved in some cells. Epicuticular deposits on the periclinal walls are absent. It is concluded that the use of macro and micromorphological characteristics of seeds of these species for clearer diagnosis at the stage of fruiting is low informative.

The Potential of Fucose-Containing Sulfated Polysaccharides As Scaffolds for Biomedical Applications

2019 ◽  
Vol 26 (35) ◽  
pp. 6399-6411 ◽  
Author(s):  
Cláudia Nunes ◽  
Manuel A. Coimbra
Keyword(s):  
Tissue Regeneration ◽  
Cell Walls ◽  
Biomedical Applications ◽  
Structural Features ◽  
Therapeutic Agents ◽  
Sulfated Polysaccharides ◽  
Clinical Use ◽  
Health Related ◽  
Pathogen Inhibition ◽  
Health Applications

Marine environments have a high quantity and diversity of sulfated polysaccharides. In coastal regions brown algae are the most abundant biomass producers and their cell walls have fucosecontaining sulfated polysaccharides (FCSP), known as fucans and/or fucoidans. These sulfated compounds have been widely researched for their biomedical properties, namely the immunomodulatory, haemostasis, pathogen inhibition, anti-inflammatory capacity, and antitumoral. These activities are probably due to their ability to mimic the carbohydrate moieties of mammalian glycosaminoglycans. Therefore, the FCSP are interesting compounds for application in health-related subjects, mainly for developing scaffolds for delivery systems or tissue regeneration. FCSP showed potential for these applications also due to their ability to form stable 3D structures with other polymers able to entrap therapeutic agents or cell and growth factors, besides their biocompatibility and biodegradability. However, for the clinical use of these biopolymers well-defined reproducible molecules are required in order to accurately establish relationships between structural features and human health applications.

Effect of particle size and delignification on the rate of digestion of hemicellulose and cellulose by cellulase in mature pangola grass stems

1983 ◽  
Vol 34 (3) ◽  
pp. 241 ◽  
Author(s):  
CW Ford
Keyword(s):  
Particle Size ◽  
Cell Walls ◽  
Trichoderma Viride ◽  
Structural Features ◽  
Cell Wall Polysaccharides ◽  
Particle Size Reduction ◽  
Digitaria Decumbens ◽  
Hemicellulose Degradation ◽  
Before And After ◽  
The Difference

Stem cell walls of pangola grass (Digitaria decumbens) were ground to two particle sizes (c. 1 and 0.1 mm diameter), and incubated with cellulase (ex. Trichoderma viride) for varying times before and after delignification. Total cell walls finely ground (0.1 mm) with a Spex Shatterbox mill were initially degraded more rapidly (to 24 h) than delignified 1 mm particles. Thereafter the delignified material was solubilized to a greater extent. Subsequent specific determinations of cell wall polysaccharides indicated that delignification increased the rate of hemicellulose degradation to a greater extent than did particle size reduction, whereas the opposite was found for cellulose. The difference between delignified and Spex-ground residues, in terms of the amount of polysaccharide digested, was much greater for cellulose than hemicellulose. It is concluded that structural features play a more important role in limiting cellulase degradation of cellulose than does association with lignin, the reverse being so for hemicellulose.

MICROSTRUCTURE ANALYSIS OF MOSO BAMBOO (Phyllostachys pubescens MAZEL) SURFACE AFTER UV RADIATION

2019 ◽  
Vol 27 (01) ◽  
pp. 1950090
Author(s):  
HAIXIA YU ◽  
XIN PAN ◽  
WEIMING YANG ◽  
WENFU ZHANG ◽  
XIAOWEI ZHUANG
Keyword(s):  
Uv Radiation ◽  
Cell Walls ◽  
Uv Light ◽  
Parenchyma Cell ◽  
Moso Bamboo ◽  
Thick Wall ◽  
Phyllostachys Pubescens ◽  
Thin Wall ◽  
Intercellular Spaces ◽  
Parenchyma Cell Walls

Bamboo material is widely used in outdoor applications. However, they are easily degraded when exposed to sunlight, their smooth surface will gradually turn to rough, and small cracks will appear and finally develop to large cracks. The paper presents a first-time investigation on the microstructure changes in the tangential section of Moso bamboo (Phyllostachys pubescens Mazel) radiated by artificial UV light. The results showed that the cracks mainly appeared at intercellular spaces of fibers where lignin content was high, the parenchyma cell walls and neighbor pits where the cell wall was very thin and more vulnerable than the other parts. In addition, the part of raised area and pit cavity tended to absorb more UV light radiation and showed more and larger cracks than the otherwhere. Cracks at the intercellular spaces of fibers were larger and bigger than those on the parenchyma cell walls. The cracks on the pits of the parenchyma cell walls normally appeared at one pit and then extended to the several surrounding pits. Bordered pits cavity showed more and larger cracks than the pits on the thin wall cells. The simple pits on the thick wall cells and the fiber cells were unaffected by UV radiation.

scholarly journals Bathymetric and morphometric surveys of the Montebello Lakes, Chiapas

2016 ◽  
Vol 75 (s1) ◽  
Author(s):  
Javier Alcocer ◽  
Luis A. Oseguera ◽  
Guillermo Sánchez ◽  
Circe G. González ◽  
Joaquín R. Martínez ◽  
...  
Keyword(s):  
Shallow Lakes ◽  
National Park ◽  
Main Axis ◽  
Morphometric Parameters ◽  
Maximum Depth ◽  
Ramsar Convention ◽  
Surface Areas ◽  
Physical Chemical ◽  
Average Maximum ◽  
Karst Lake

This study presents the first bathymetric surveys and descriptions of the morphometric parameters of the major lakes of the national park and Ramsar Convention site <em>Lagunas de Montebello</em>, Chiapas, Mexico and represents the first contribution on these limnologically unknown lakes. The morphology of lacustrine basins has an important influence on the physical, chemical and biological dynamics, and limnological research must consider the bathymetry and the related morphometric parameters of the lakes. Of the more than 50 lakes that make up this karst lake system (including dolines, uvalas and poljes), 18 representative lakes were selected along a NW-SE transect. The lakes have widely varying dimensions and include small and deep, small and shallow, large and deep, and large and shallow lakes. The shapes of the lakes vary from circular to elliptical, and the basin resembles an inverted truncated cone. The orientation of the main axis follows the structural orientations of the karst landscape (i.e., faults, fractures and folds). The maximum lengths range from 0.14 to 3.2 km, the surface areas range from 1.1 ha to 306.6 ha, and the lake volumes range from 0.00004 to 0.08852 km<sup>3</sup>. Six lakes are among the deepest lakes in Mexico and have an average maximum depth of more than 50 m; the deepest lake has a maximum depth of 198 m. These depths favor prolonged stratification, which increases the probability of accumulating pollutants.

scholarly journals Inverse Design of Nanoporous Crystalline Reticular Materials with Deep Generative Models

2020 ◽  
Author(s):  
Zhenpeng Yao ◽  
Benjamin Sanchez-Lengeling ◽  
N. Scott Bobbitt ◽  
Benjamin J. Bucior ◽  
Sai Govind Hari Kumar ◽  
...  
Keyword(s):  
Self Assembly ◽  
Metal Organic Framework ◽  
Internal Surface ◽  
Building Blocks ◽  
Structural Features ◽  
Generative Models ◽  
Combinatorial Design ◽  
Surface Areas ◽  
Molecular Building Blocks ◽  
Metal Organic

Reticular frameworks are crystalline porous materials that form <i>via</i> the self-assembly of molecular building blocks (<i>i.e.</i>, nodes and linkers) in different topologies. Many of them have high internal surface areas and other desirable properties for gas storage, separation, and other applications. The notable variety of the possible building blocks and the diverse ways they can be assembled endow reticular frameworks with a near-infinite combinatorial design space, making reticular chemistry both promising and challenging for prospective materials design. Here, we propose an automated nanoporous materials discovery platform powered by a supramolecular variational autoencoder (SmVAE) for the generative design of reticular materials with desired functions. We demonstrate the automated design process with a class of metal-organic framework (MOF) structures and the goal of separating CO<sub>2</sub> from natural gas or flue gas. Our model exhibits high fidelity in capturing structural features and reconstructing MOF structures. We show that the autoencoder has a promising optimization capability when jointly trained with multiple top adsorbent candidates identified for superior gas separation. MOFs discovered here are strongly competitive against some of the best-performing MOFs/zeolites ever reported. This platform lays the groundwork for the design of reticular frameworks for desired applications.

scholarly journals STRUCTURAL AND CHEMICAL CHARACTERISTIC OF PECTIN FROM PICEA ABIES GREENERY

2020 ◽  
pp. 59-71
Author(s):  
Evgeniy Gennad'yevich Shakhmatov ◽  
Elena Nikolayevna Makarova
Keyword(s):  
Cell Walls ◽  
New Technologies ◽  
Chemical Characteristic ◽  
Structural Features ◽  
Exchange Chromatography ◽  
Raw Material ◽  
Rhamnogalacturonan I ◽  
Wood Processing ◽  
Potential Source ◽  
Pectin Substances

The present work aimed to determine structural features of polysaccharides derived from the P. abies foliage by extraction with a (NH4)2C2O4 solution. The isolated polysaccharide was studied in detail by the methods of ion exchange chromatography, partial acidic hydrolys and NMR spectroscopy. It was shown that this polysaccharide contained polymers of various structures. The major constituents of PAO were low-methoxyl and low-acetylated 1,4-a-D-galacturonan and by minor parts of partly 2-O- and/or 3-O- acetylated rhamnogalacturonan-I (RG-I). The side carbohydrate chains of the branched region of RG-I were represented predominantly by highly branched 1,5-a-L-arabinan and minor portions of 1,4-β-D-galactan. In addition to the dominant pectins, polysaccharide PAO contained binding glycans of the glucomannans class, which indicated a close interaction of these polysaccharides in the cell walls. Thus, the structural features of pectin woody P. abies, extracted with a solution of (NH4)2C2O4, were first determined. It can be concluded that P. abies woody greens, a large tonnage waste from the wood processing industry, can be considered as a potential source of pectin substances. The results of studying the structure of components of woody green P. abies can be the basis for the development and improvement of new technologies for the integrated use of this raw material.

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