The nature of reaction wood. IX. Anomalous cases of reaction anatomy

1964 ◽  
Vol 12 (2) ◽  
pp. 173 ◽  
Author(s):  
G Scurfield
Keyword(s):  
Cross Sectional Area ◽  
Axial Position ◽  
Vertical Position ◽  
Reaction Wood ◽  
Vascular Bundles ◽  
Sectional Area ◽  
Cross Sectional ◽  
Gelatinous Layer ◽  
Stage Of Development ◽  
Wood Fibres

The reaction anatomy of 14 species of Acacia, Lagunaria pattersoni, and the woody monocotyledons Dracaena fragrans and D. marginata was examined with light, polarizing, and ultraviolet microscopes. Notable features of the reaction wood fibres of Acacia spp. were: the absence of birefringence in the sublayers of the "gelatinous" layer at all stages of their deposition; the absence of radial striations in the gelatinous layer; the frequency of occurrence of fibres lacking protoplasts and with convoluted gelatinous layers at some intermediate stage of development; the relatively wide separation of stages of gelatinous layer formation in passing from cambium towards pith; and the poor adherence of the gelatinous layer to previously formed cell wall layers. It was concluded that the forces bringing about gelatinous layer deposition were either weaker or slower to develop, or both, than in species such as Tristania conferta. Possible reasons for this are discussed. Deposition of starch grains in reaction wood fibres occurred in all Acacia spp, towards the end of the growing season. A gelatinous layer did not occur in reaction wood fibres of Lagunaria pattersoni. These differed from normal fibres only in the thinness of their walls and their relatively large cross-sectional area. Examination of the wall structure of phloem fibres indicated that changes in microfibril orientation towards a more axial position which occurred in layer S2 of primary phloem fibres were accelerated on the upper sides of bent stems. The significance of this feature, and of possible tensions developed in the outer cortex and epidermis on the upper sides of bent stems because of accelerated phloem and xylem development, are discussed in relation to mechanisms whereby such stems may recover to a vertical position. The number of vascular bundles and the wall thickness and extent of lignification of the fibres of the bundle sheaths, were increased on the upper sides of horizontally grown stems of Dracaena spp. The radial width of the cortex and the cross-sectional area of cortical cells were less than on the lower sides of the stems.

Physical strength and its relation to leaf anatomical characteristics of nine forage grasses

2004 ◽  
Vol 52 (6) ◽  
pp. 799 ◽  
Author(s):  
Ji Min Zhang ◽  
Akio Hongo ◽  
Masahiro Akimoto
Keyword(s):  
Shear Strength ◽  
Festuca Arundinacea ◽  
Dactylis Glomerata ◽  
Cross Sectional Area ◽  
Vascular Bundles ◽  
Sectional Area ◽  
Forage Grasses ◽  
Cross Sectional ◽  
Anatomical Characteristics ◽  
Physical Strength

Nine species of forage grasses (five C3 species and four C4 species) were planted in a controlled-environment glasshouse. The C3 plants were Festuca arundinacea Schreb, Dactylis glomerata L., Phleum pratense L., Lolium perennel L. and Poa pratensis L.; the C4 plants were Chloris gayana Kunch., Cynodon dactylon (L.) Pers., Paspalum dilatatum Poir. and Sorghum halenpense (L.) Pers. The number of major vascular bundles and minor vascular bundles, cross-sectional area, the area and proportion of sclerenchyma in a cross-section, thickness of leaf blade, and tensile and shear strength were investigated in order to determine the relationship between physical strength and anatomical characteristics. Physical strength and anatomical characteristics of leaf blades showed significant (P < 0.01) variation between species. Significant correlations were detected between tensile strength and cross-sectional area in forage grasses except Festuca arundinacea. Festuca arundinacea, Dactylis glomerata, Phleum pratense, Chloris gayana and Sorghum halenpense showed significant correlations of tensile strength with the number of major vascular bundles. Festuca arundinacea, Dactylis glomerata and Lolium perennel showed significant correlations of shear strength with cross-sectional area. Festuca arundinacea, Dactylis glomerata and Paspalum dilatatum showed significant correlations of shear strength with the number of major vascular bundles. The proportion of sclerenchyma in a cross-section showed poor correlations with tensile and shear strength. Thickness of leaf blade showed poor correlations with tensile and shear strength except in Dactylis glomerata. Physical strength and anatomical characteristics of leaf blades of the C3 group differed significantly (P < 0.01) when compared with the C4 group except for cross-sectional area. Tensile and shear strength showed significant correlations with cross-sectional area, sclerenchyma area and the number of vascular bundles when all nine species were treated as one group.

Morphometric analysis of Rhynia and Asteroxylon: testing functional aspects of early land plant evolution

Paleobiology ◽  
2000 ◽  
Vol 26 (3) ◽  
pp. 405-418 ◽  
Author(s):  
A. Roth-Nebelsick ◽  
G. Grimm ◽  
V. Mosbrugger ◽  
H. Hass ◽  
H. Kerp
Keyword(s):  
Water Transport ◽  
Land Plant ◽  
Plant Evolution ◽  
Cross Sectional Area ◽  
Land Plants ◽  
Limiting Factor ◽  
Vascular Bundles ◽  
Sectional Area ◽  
Cross Sectional ◽  
Early Land

New morphometric data gathered from cross-sections of two Lower Devonian land plants (Rhynia gwynne-vaughanii and Asteroxylon mackiei) are interpreted in terms of the evolution of the function of vascular bundles in early land plants. The following conclusions can be drawn from these new data: (1) The ratio of the cross-sectional area of the xylem (representing the conducting volume supplying the axis with water) to the xylem perimeter (representing the “contact area” between xylem and parenchyma through which water leaves the xylem and enters the parenchyma) is not constant for Rhynia axes, almost constant for Asteroxylon axes, and different between Rhynia and Asteroxylon. Thus, Bowers hypothesis that the ratio of cross-sectional area of the xylem to xylem perimeter is constant during ontogenetic development is true for Asteroxylon. That this ratio is constant during phylogeny, however, is not supported by our data. (2) The ratio between cross-sectional area of xylem to parenchyma is higher in Asteroxylon than in Rhynia. (3) As predicted by previous computer simulations, the ratio of the xylem perimeter to the axis perimeter plays a major role in determining water transport performance of the transpiring axis. This ratio is constant within ontogeny but is different in Asteroxylon and Rhynia. In Asteroxylon axes, this ratio is about twice as large as in Rhynia axes. (4) Contrary to the expectations, the distance between the outermost layer of the xylem and the transpiring surface, which represents the low-conductivity pathway through the parenchyma, appears not to be a limiting factor for the water transport in axes of Rhynia and Asteroxylon. (5) From the analysis of the geometric parameters, it is evident that Rhynia and Asteroxylon with their distinct stelar geometries represent two different constructional types for which no transitional stages are known.

scholarly journals The Phloem of the Wheat Stem in Relation to Requirements for Assimilate by The Ear

1970 ◽  
Vol 23 (4) ◽  
pp. 743 ◽  
Author(s):  
LT Evans ◽  
RL Dunstone ◽  
HM Rawson ◽  
RF Williams
Keyword(s):  
Light Intensity ◽  
Wild Species ◽  
High Light Intensity ◽  
High Light ◽  
Cross Sectional Area ◽  
Main Stem ◽  
Vascular Bundles ◽  
Sectional Area ◽  
Cross Sectional ◽  
Related Wild Species

The cross-sectional area of the phloem and the number of vascular bundles at the top of the main stem were determined in 22 diploid, tetraploid, and hexaploid wheats and related wild species grown at 21{16�C in 16-hr days of high light intensity.

scholarly journals ДО ВИЗНАЧЕННЯ УРІВНОВАЖУВАЛЬНОЇ НАВАНТАГИ НА ШПАНГОУТ ОДНОПАЛУБНОГО ФЮЗЕЛЯЖУ

2021 ◽  
pp. 113-121
Author(s):  
А. Г. Дибир ◽  
А. А. Кирпикин ◽  
Н. И. Пекельный
Keyword(s):  
Cross Section ◽  
Cross Sectional Area ◽  
Torsional Stiffness ◽  
Vertical Position ◽  
Sectional Area ◽  
Cross Sectional ◽  
Optimal Position ◽  
Load Bearing ◽  
The Cross ◽  
Fuselage Skin

With the optimal design of the fuselage, a very important issue is the choice of the optimal position of the load-bearing floor in the cross-section of the fuselage.Depending on the relative position of the load-bearing floor, the reduced thickness of the floor, the scheme of fastening the floor to the frames and the ratio of the reduced thicknesses of the fuselage skin and the floor, the position of the center of stiffness of the fuselage cross-section changes, the torsional stiffness of the fuselage. This leads to a change in torque, a redistribution of shear flows, a redistribution of flattening loads on the frame from the bending of the fuselage.In this work, two schemes of fastening the floor to the frame are considered - a rigid, torque connection and a hinged one. In this case, the frame takes up additional load from the floor. The fuselage is considered as a thin-walled rod, loaded with horizontal and vertical shear forces, torque and flattening forces from the fuselage bending.For reliability, the calculation of the position of the center of stiffness in a double-closed cross-section was carried out by two methods: a fictitious force and a fictitious moment. The influence of various parameters on the location of the center of rigidity was investigated. The influence of the vertical position of the floor, the ratio of the reduced thicknesses of the floor and the fuselage skin and the cross-sectional area of the beams of the floor attachment to the fuselage on the position of the center of stiffness was evaluated. Diagrams of these dependencies were constructed based on the results of calculations. The dependence of the torsional stiffness on the position of the floor and the ratio of the reduced thicknesses of the floor and the fuselage skin was investigated. Based on the calculation results, a diagram of these dependencies was built. Various constructive solutions were considered for fastening the floor to the fuselage skin: with their direct connection and with the floor support only on the beam. The floor loading from flattening loads caused by the bending of the fuselage was studied. The diagram of the loading of the frame and the floor from flattening loads is shown.According to the diagrams, you can choose the optimal vertical position of the floor, the reduced floor thickness and the cross-sectional area of the beam

scholarly journals Grapevine bud fertility under conditions of elevated carbon dioxide

OENO One ◽  
2019 ◽  
Vol 53 (2) ◽  
Author(s):  
Yvette Wohlfahrt ◽  
Cassandra Collins ◽  
Manfred Stoll
Keyword(s):  
Carbon Dioxide ◽  
Early Stage ◽  
Elevated Carbon Dioxide ◽  
Cross Sectional Area ◽  
Yield Potential ◽  
Cabernet Sauvignon ◽  
Sectional Area ◽  
Cross Sectional ◽  
Stage Of Development ◽  
Yield Gain

Aims: Microscopic bud dissection is commonly used to assess grapevine bud fertility and thereby predict yield for the following season. Grapevine yield has been shown to increase in response to elevated carbon dioxide concentration (eCO2), and this yield gain has been demonstrated under Free Air Carbon dioxide Enrichment (FACE). However, the effects of eCO2 on bud fertility and their relation to yield gain have not been investigated. Little is known about which stages of development and which yield components are affected. The aim of this study was to determine the number of inflorescence primordia (IP) per node, the cross-sectional area of the IP, and the incidence of primary bud necrosis (PBN) in grapevine compound buds grown under conditions of ambient CO2 concentration (aCO2) and eCO2, and to relate the data to yield parameters of field-grown vines at harvest.Methods and results: Plant material was collected in February 2016 and February 2017 from two Vitis vinifera L. cultivars, Riesling and Cabernet-Sauvignon, growing at the VineyardFACE experimental site of Hochschule Geisenheim University (49°59¢N, 7°57¢E) in the Rheingau wine region, Germany. Bud dissections were performed at the University of Adelaide’s Waite Research Institute, Australia. Canes were stored at 4°C until dissection at room temperature. The first eight nodes of each cane were dissected and the compound buds assessed; IP number, IP cross-sectional area (evaluated by image analysis) and PBN incidence were recorded. In Riesling, no differences were found between plants grown under the two CO2 treatments in terms of IP number per node or subsequent number of bunches per shoot. Compound buds of Riesling plants grown under eCO2 had larger IP cross-sectional area; however, this did not result in higher bunch weight or yield in response to eCO2 over the 2 years. In Cabernet-Sauvignon, IP number per node was higher in plants grown under eCO2 but no changes in bunch number per shoot were found in either season. In contrast, the larger IP cross-sectional area in Cabernet-Sauvignon in response to eCO2 translated into higher bunch weight and yield in both seasons. PBN incidence of both cultivars was highest at basal node positions along the fruiting cane, except for Cabernet-Sauvignon in 2017, where both treatments showed higher incidence at the distal ends. In both cultivars, average PBN incidence along the cane was unaffected by eCO2.Conclusions: Microscopic bud dissection can be used at an early stage of vine development to predict increased bunch weight. There was evidence of a cultivar-dependent response to eCO2 in terms of bud fruitfulness. In future, it would be interesting to investigate whether higher carbohydrate levels are responsible for the increase in IP area detectable at a very early stage of development in plants grown under eCO2.Significance and impact of the study: The findings of this study contribute to our understanding of grapevine bud fertility and yield potential, particularly under changing climatic conditions.

Pelvic Canal Narrowing Caused by Triple Pelvic Osteotomy in the Dog

1994 ◽  
Vol 07 (03) ◽  
pp. 110-113 ◽  
Author(s):  
D. L. Holmberg ◽  
M. B. Hurtig ◽  
H. R. Sukhiani
Keyword(s):  
Postoperative Complications ◽  
Pelvic Osteotomy ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Canal Width ◽  
Operative Complications ◽  
Post Operative Complications

SummaryDuring a triple pelvic osteotomy, rotation of the free acetabular segment causes the pubic remnant on the acetabulum to rotate into the pelvic canal. The resulting narrowing may cause complications by impingement on the organs within the pelvic canal. Triple pelvic osteotomies were performed on ten cadaver pelves with pubic remnants equal to 0, 25, and 50% of the hemi-pubic length and angles of acetabular rotation of 20, 30, and 40 degrees. All combinations of pubic remnant lengths and angles of acetabular rotation caused a significant reduction in pelvic canal-width and cross-sectional area, when compared to the inact pelvis. Zero, 25, and 50% pubic remnants result in 15, 35, and 50% reductions in pelvic canal width respectively. Overrotation of the acetabulum should be avoided and the pubic remnant on the acetabular segment should be minimized to reduce postoperative complications due to pelvic canal narrowing.When performing triple pelvic osteotomies, the length of the pubic remnant on the acetabular segment and the angle of acetabular rotation both significantly narrow the pelvic canal. To reduce post-operative complications, due to narrowing of the pelvic canal, overrotation of the acetabulum should be avoided and the length of the pubic remnant should be minimized.

DETERMINATION OF THE FUNCTION OF THE ROD’S CROSS-SECTIONAL AREA USING VIBRATION EIGENFREQUENCIES

2020 ◽  
Vol 0 (4) ◽  
pp. 19-24
Author(s):  
I.M. UTYASHEV ◽  
◽  
A.A. AITBAEVA ◽  
A.A. YULMUKHAMETOV ◽  
◽  
...  
Keyword(s):  
Cross Sectional Area ◽  
Variable Cross ◽  
Sectional Area ◽  
Longitudinal Vibrations ◽  
Cross Sectional ◽  
Method Error ◽  
Various Boundary Conditions ◽  
Elastic Fixation ◽  
Crosssectional Area

The paper presents solutions to the direct and inverse problems on longitudinal vibrations of a rod with a variable cross-sectional area. The law of variation of the cross-sectional area is modeled as an exponential function of a polynomial of degree n . The method for reconstructing this function is based on representing the fundamental system of solutions of the direct problem in the form of a Maclaurin series in the variables x and λ. Examples of solutions for various section functions and various boundary conditions are given. It is shown that to recover n unknown coefficients of a polynomial, n eigenvalues are required, and the solution is dual. An unambiguous solution was obtained only for the case of elastic fixation at one of the rod’s ends. The numerical estimation of the method error was made using input data noise. It is shown that the error in finding the variable crosssectional area is less than 1% with the error in the eigenvalues of longitudinal vibrations not exceeding 0.0001.

Changes in the parameters of nasal breathing and parameters of the upper respiratory tract during orthognathic operations in patients with II and III skeletal class of jaw anomalies

2020 ◽  
pp. 22-27
Author(s):  
S.Sh. Gammadaeva ◽  
M.I. Misirkhanova ◽  
A.Yu. Drobyshev
Keyword(s):  
Respiratory Tract ◽  
Nasal Cavity ◽  
Nasal Septum ◽  
Cross Sectional Area ◽  
Upper Respiratory Tract ◽  
Sectional Area ◽  
Nasal Breathing ◽  
Cross Sectional ◽  
Skeletal Class ◽  
Upper Respiratory

The study analyzed the functional parameters of nasal breathing, linear parameters of the nasal aperture, nasal cavity and nasopharynx, volumetric parameters of the upper airways in patients with II and III skeletal class of jaw anomalies before and after orthognathic surgery. The respiratory function of the nose was assessed using a rhinomanometric complex. According to rhinoresistometry data, nasal resistance and hydraulic diameter were assessed. According to the data of acoustic rhinometry, the minimum cross-sectional area along the internal valve, the minimum cross-sectional area on the head of the inferior turbinate and nasal septum and related parameters were estimated. According to the CBCT data, the state of the nasal septum, the inferior turbinates, the nasal aperture, the state of the nasal cavity, and the linear values of the upper respiratory tract (nasopharynx) were analyzed. The patients were divided into 4 groups according to the classification of the patency of the nasal passages by

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