NITROGEN IN WOOD AND ITS ROLE IN WOOD DETERIORATION

1966 ◽  
Vol 44 (11) ◽  
pp. 1539-1554 ◽  
Author(s):  
Ellis B. Cowling ◽  
William Merrill
Keyword(s):  
Cell Wall ◽  
Continuous Process ◽  
Wood Fiber ◽  
Significant Loss ◽  
Chemical Form ◽  
Present Knowledge ◽  
Xylem Parenchyma ◽  
Fiber Cells ◽  
Parenchyma Cells ◽  
Wood Deterioration

Based on present knowledge of the origin, amounts, chemical form, and distribution of nitrogen (N) in wood, hypotheses are proposed to explain radial gradients in N content that exist across the xylem cylinder of tree stems: (1) N in the cytoplasm of developing wood cells is diluted by apposition of cell wall substances; (2) after maturation of wood fiber cells, N in their cytoplasm is removed by elution into the transpiration stream; (3) death of xylem parenchyma cells during aging of sapwood and formation of heartwood is accompanied by removal of much of the N in their cytoplasm. Hypotheses 2 and 3 above suggest strongly that trees possess an internal recycling mechanism for conservation and reuse of the N in the cytoplasm of xylary cells.Although the supply of N in wood is meager, wood-destroying fungi readily metabolize the carbon-rich constituents of wood and produce large fruiting structures that release vast numbers of spores in nature. To account for these capacities, we postulate that these fungi employ one or more of the following three mechanisms: (1) preferential allocation of N obtainable from wood to substances and pathways highly efficient in the use of wood constituents; (2) reuse of N obtainable from wood by a dynamic and continuous process of autolysis and reuse without significant loss of N; (3) utilization of N sources outside the wood itself, for example, by fixation of atmospheric N.

The Protective Layer as an Extension of the Apoplast

IAWA Journal ◽  
1993 ◽  
Vol 14 (2) ◽  
pp. 163-171 ◽  
Author(s):  
J. R. Barnett ◽  
P. Cooper ◽  
Lynda J. Bonner
Keyword(s):  
Cell Wall ◽  
Protective Layer ◽  
Xylem Parenchyma ◽  
Pit Membrane ◽  
Parenchyma Cells ◽  
Deep Supercooling ◽  
Dying Cells ◽  
Tylose Formation ◽  
Universal Application

The protective layer between the cell wall and plasmalemma of xylem parenchyma cells has variously been suggested to be involved in protection of the protoplast from attack by autolytic enzymes from neighbouring, dying cells, tylose formation, deep supercooling of xylem, and strengthening of the pit. None of these ideas has universal application to all species in which parenchyma cells possess a protective layer. It is proposed instead, that the protective layer is primarily laid down in order to preserve apoplastic continuity around the protoplast of a lignified cell, bringing the entire plasmalemma surface, and not just that part of it in contact with the porous pit membrane, into contact with the apoplast. If this is so, then other functions may be coincidental, or have arisen secondarily.

Effects of DCPA on Tomato Hypocotyl Tissue

Weed Science ◽  
1972 ◽  
Vol 20 (5) ◽  
pp. 434-439 ◽  
Author(s):  
J. LaMar Anderson ◽  
Bijan Shaybany
Keyword(s):  
Cell Wall ◽  
Lycopersicon Esculentum ◽  
Cell Wall Composition ◽  
Xylem Parenchyma ◽  
Parenchyma Cells ◽  
Hypocotyl Tissue ◽  
Air Cavities

Dimethyl tetrachloroterephthalate (DCPA) caused localized swelling of the hypocotyl of tomato(Lycopersicon esculentumMill. ‘VF-99′). DCPA caused phloem and xylem parenchyma cells to become multinucleate and to develop into masses undifferentiated tissue within the stele of the tomato hypocotyl. Xylem procambium differentiated earlier than that of controls and matured into shortened and often disconnected elements. Xylem formed prior to treatment was often disrupted due to pressure from the dividing xylem parenchyma. Xylem parenchyma tended to break down resulting in the formation of air cavities within the stele. Cells in the stele of treated hypocotyls tended to stain more intensely with safranin than did the cells in the steles of untreated tomato hypocotyls indicating a difference in cell wall composition. Treated tissue had a higher concentration of total oxalates than did untreated tissue.

Cytochemistry of defense responses in cassava infected by Xanthomonas campestris pv. manihotis

1996 ◽  
Vol 42 (11) ◽  
pp. 1131-1143 ◽  
Author(s):  
K. Kpémoua ◽  
B. Boher ◽  
M. Nicole ◽  
P. Calatayud ◽  
J. P. Geiger
Keyword(s):  
Cell Wall ◽  
Bacterial Growth ◽  
Xanthomonas Campestris ◽  
Secondary Cell Wall ◽  
Defense Responses ◽  
Resistant Variety ◽  
Xylem Parenchyma ◽  
Callose Deposition ◽  
Wide Range ◽  
Parenchyma Cells

Stems of susceptible and resistant cassava plants have been cytologically investigated for their defense reactions to an aggressive strain of Xanthomonas campestris pv. manihotis. Histochemistry, in conjunction with gold cytochemistry, revealed that in susceptible and resistant plants, phloem and xylem parenchyma cells displayed a wide range of responses that limited the bacterial growth within the infected plants. Lignification and suberization associated with callose deposition were effective mechanisms that reinforced host barriers in the phloem. In the infected xylem, vessels were plugged by a material of pectic and (or) lignin-like origin. Flavonoids have been seen to be incorporated in secondary cell wall coatings. These reactions occurred at a higher intensity in the resistant plants. The number of phoem and xylem cells producing autofluorescent compounds was higher in infected resistant plants than in susceptible plants. Reactions have been observed in the resistant variety only, such as secretion of phenol-like molecules by tyloses and hyperplasic activity of phloem cells that compartmentalized bacterial lysis pockets, which are potent secondary inoculum sources.Key words: lignin, suberin, callose, phenol, tylose, flavonoid, pectin.

scholarly journals Changes in structure of red pepper (Capsicum annuum L.) seedlings shoots under aluminum stress conditions

2012 ◽  
Vol 60 (1) ◽  
pp. 85-93 ◽  
Author(s):  
Agata Konarska
Keyword(s):  
Cell Wall ◽  
Capsicum Annuum ◽  
Red Pepper ◽  
Outer Cell ◽  
Aluminum Stress ◽  
Water Culture ◽  
Anatomical Features ◽  
Parenchyma Cells ◽  
Al Treatment ◽  
Outer Cell Wall

The seedlings of the red pepper (<i>Capsicum annuum</i> L.) cv. Trapez grown in water culture for a period of 14 days with Al (0, 10, 20 and 40 mg·dm<sup>-3</sup> AlCl<sub>3</sub>·6 H<sub>2</sub>O). Some morphological and anatomical features of red pepper shoots were analyzed. Reduction in height and diameter of stems as well as decrease in fresh mass of shoots were observed after Al-treatment. In the hypocotyl the thickness of cortex parenchyma layer and the size of their cells were reduced. The aluminum treatment resulted in the increased in thickness of the epidermis outer cell wall. Under Al stress in the cotrex and the central cylinder parenchyma cells were present numerous enlarge plastids which contained large grains of starch and dark little bodies which were possible aluminum deposits. They weren`t observed in control seedlings.

scholarly journals Mechanical Function of Lignin and Hemicelluloses in Wood Cell Wall Revealed with Microtension of Single Wood Fiber

BioResources ◽  
2013 ◽  
Vol 8 (2) ◽  
Author(s):  
Shuang-Yan Zhang ◽  
Chuan-Gui Wang ◽  
Ben-Hua Fei ◽  
Yan Yu ◽  
Hai-Tao Cheng ◽  
...  
Keyword(s):  
Cell Wall ◽  
Wood Cell Wall ◽  
Wood Fiber ◽  
Mechanical Function

Resistance of hardwood vessels to degradation by white rot Basidiomycetes

1988 ◽  
Vol 66 (9) ◽  
pp. 1841-1847 ◽  
Author(s):  
Robert A. Blanchette ◽  
John R. Obst ◽  
John I. Hedges ◽  
Karen Weliky
Keyword(s):  
Cell Wall ◽  
Secondary Wall ◽  
White Rot ◽  
Fungal Decay ◽  
Acacia Koa ◽  
Monomer Composition ◽  
Lignin Removal ◽  
Vessel Elements ◽  
Parenchyma Cells ◽  
Unusual Type

White stringy rot, an unusual type of selective fungal decay, can be found in wood of some dicotyledonous angiosperms. Stages of advanced decay consist of a mass of vessel elements with only remnants of other cells adhering to the vessel walls. Degradation by various white rot Basidiomycetes causes loss of fibers, fiber tracheids, and parenchyma cells but not vessels. In wood of Acacia koa var. koa with a white pocket rot caused by Phellinus kawakamii, fibers and parenchyma cells were preferentially delignified. After extensive lignin removal the cellulose remaining in the secondary wall was degraded. Large vessel elements remained relatively intact after other cells were completely degraded. The resistance of vessels to degradation appears to be due to their high ligninxarbohydrate ratio, lignin monomer composition, and cell wall morphology.

Cell Wall Pore Structures of Bamboo as Relation to Species and Tissue Types

2021 ◽  
Author(s):  
Mengdan Cao ◽  
Wenting Ren ◽  
Jiawei Zhu ◽  
Hankun Wang ◽  
Juan Guo ◽  
...  
Keyword(s):  
Cell Wall ◽  
Wood Species ◽  
Distinct Species ◽  
Bamboo Species ◽  
Compact Structure ◽  
Pore Structures ◽  
Mesopore Structure ◽  
Parenchyma Cells ◽  
Bamboo Fibers ◽  
Cell Wall Porosity

Abstract Efficient convention of bamboo biomass into biofuel and biomaterials, as well as chemical treatment are both highly related to the porosity of cell wall. The present work characterizes the micropore and mesopore structure in cell walls of six different bamboo species and tissue types using CO2 and N2 adsorption. Two plantation wood species were also tested for comparison. Bamboo species normally showed lower cell wall porosity (2.64%-3.75%) than wood species (3.98%-5.06%), indicating a more compact structure for bamboo than wood. A distinct species dependence of cell wall pore structures and porosity was also observed. Furthermore, the cell wall pore structure and porosity are shown to be tissue-specific, as the parenchyma cells exhibit higher pore volume and porosity compared to bamboo fibers. The obtained results give new explanations on the known facts that both bamboo and bamboo fibers exhibit higher biomass recalcitrance as compared to wood and bamboo parenchyma cells, constructing the base of pretreatment optimization and subsequent processing for bamboo-derived biofuels and biomaterials.

scholarly journals Colonization of Fiber Cells by Colletotrichum graminicola in Wounded Maize Stalks

2007 ◽  
Vol 97 (4) ◽  
pp. 438-447 ◽  
Author(s):  
C. Venard ◽  
L. Vaillancourt
Keyword(s):  
Type Strain ◽  
Wild Type Strain ◽  
Pathogen Resistance ◽  
Vascular Bundles ◽  
Colletotrichum Graminicola ◽  
Wild Type ◽  
Wound Site ◽  
Fiber Cells ◽  
Parenchyma Cells ◽  
Maize Stalks

Colonization of wounded maize stalks by a wild-type strain of Colletotrichum graminicola was compared with colonization by a C. graminicola mutant that is avirulent on maize leaves, and by a wild-type strain of C. sublineolum that is normally a pathogen of sorghum but not maize. Local infection by all strains at the wound site resulted in formation of primary lesions consisting of disintegrated parenchyma cells beneath an intact rind and epidermis. However, subsequent rapid longitudinal expansion of the primary lesion occurred only in infections with the wild-type C. graminicola strain, and proceeded specifically through the fiber cells associated with the vascular bundles and the rind. Hyphae emerged from the fiber cells to produce discontinuous secondary lesions. There was no evidence that C. graminicola is a vascular wilt pathogen. Resistance of wounded cv. Jubilee maize stalks to the mutant strain of C. graminicola and to C. sublineolum was associated with restriction of colonization and spread of the pathogen through the fibers, as well as with the limitation of localized destruction of parenchyma cells at the wound site.

scholarly journals The Cell Wall Structure of Xylem Parenchyma

1952 ◽  
Vol 5 (2) ◽  
pp. 223 ◽  
Author(s):  
AB Wardrop ◽  
HE Dadswell
Keyword(s):  
Cell Wall ◽  
Fine Structure ◽  
Secondary Cell Wall ◽  
Primary Cell Wall ◽  
Wall Structure ◽  
Xylem Parenchyma ◽  
Cell Axis ◽  
X Ray ◽  
Ray Methods ◽  
Longitudinal Cell

The fine structure of the cell wall of both ray and vertical parenchyma has been investigated. In all species examined secondary thickening had occurred. In the primary cell wall the micellar orientation was approximately trans"erse to the longitudiJ)aI cell axis. Using optical and X-ray methods the secondary cell wall was shown to possess a helical micellar organization, the micelles being inclined between 30� and 60� to the longitudinal cell axis.

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