Cell twisting during desiccation reveals axial asymmetry in wall organization

Plant cell size and shape are tuned to their function and specified primarily by cellulose microﬁbril (CMF) patterning of the cell wall. Arabidopsis thaliana leaf trichomes are responsible for protecting plants against environmental elements and are unicellular structures that employ a highly anisotropic cellulose wall to extend and taper, generating pointed branches. During elongation, the mechanisms by which shifts in fiber orientation generate cells with predictable sizes and shapes are unknown. Specifically, the axisymmetric growth of trichome branches is often thought result from axisymmetric CMF patterning. Here, we analyzed the direction and degree of twist of branches after desiccation to reveal the presence of an asymmetric cell wall organization with a left-hand bias. CMF organization, quantified using computational modeling, suggests a limited reorientation of microfibrils during growth and maximum branch length limited by the wall axial stiffness. The model provides a mechanism for CMF asymmetry, which occurs after the branch bending stiffness becomes low enough that ambient bending affects the principal stresses. After this stage, the CMF synthesis results in a constant bending stiffness for longer branches. The resulting natural frequency of branches after a length of 200 μm falls within the range of the sounds associated with many insects.

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Triple-Stranded Left-Hand Helical Cellulose Microfibril inAcetobacter xylinumand in Tobacco Primary Cell Wall

ACS Symposium Series - Plant Cell Wall Polymers ◽

10.1021/bk-1989-0399.ch020 ◽

1989 ◽

pp. 278-298 ◽

Cited By ~ 6

Author(s):

George C. Ruben ◽

Gordon H. Bokelman ◽

William Krakow

Keyword(s):

Cell Wall ◽

Cellulose Microfibril ◽

Primary Cell ◽

Primary Cell Wall ◽

Left Hand

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Regulation Of The Microtubule Cytoskeleton And Cell Wall Development In Arabidopsis Thaliana

10.30707/etd2020.fornero.c ◽

2019 ◽

Author(s):

Christy J. Fornero

Keyword(s):

Arabidopsis Thaliana ◽

Cell Wall ◽

Microtubule Cytoskeleton ◽

Cell Wall Development

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Inhibition of cell expansion enhances cortical microtubule stability in the root apex of Arabidopsis thaliana

Journal of Biological Research-Thessaloniki ◽

10.1186/s40709-021-00143-8 ◽

2021 ◽

Vol 28 (1) ◽

Author(s):

Veronica Giourieva ◽

Emmanuel Panteris

Keyword(s):

Arabidopsis Thaliana ◽

Cell Wall ◽

Cell Expansion ◽

Cortical Microtubule ◽

Root Apex ◽

Cellulose Synthase ◽

Cellulose Biosynthesis ◽

Cortical Microtubules ◽

Wild Type ◽

Microtubule Stability

Abstract Background Cortical microtubules regulate cell expansion by determining cellulose microfibril orientation in the root apex of Arabidopsis thaliana. While the regulation of cell wall properties by cortical microtubules is well studied, the data on the influence of cell wall to cortical microtubule organization and stability remain scarce. Studies on cellulose biosynthesis mutants revealed that cortical microtubules depend on Cellulose Synthase A (CESA) function and/or cell expansion. Furthermore, it has been reported that cortical microtubules in cellulose-deficient mutants are hypersensitive to oryzalin. In this work, the persistence of cortical microtubules against anti-microtubule treatment was thoroughly studied in the roots of several cesa mutants, namely thanatos, mre1, any1, prc1-1 and rsw1, and the Cellulose Synthase Interacting 1 protein (csi1) mutant pom2-4. In addition, various treatments with drugs affecting cell expansion were performed on wild-type roots. Whole mount tubulin immunolabeling was applied in the above roots and observations were performed by confocal microscopy. Results Cortical microtubules in all mutants showed statistically significant increased persistence against anti-microtubule drugs, compared to those of the wild-type. Furthermore, to examine if the enhanced stability of cortical microtubules was due to reduced cellulose biosynthesis or to suppression of cell expansion, treatments of wild-type roots with 2,6-dichlorobenzonitrile (DCB) and Congo red were performed. After these treatments, cortical microtubules appeared more resistant to oryzalin, than in the control. Conclusions According to these findings, it may be concluded that inhibition of cell expansion, irrespective of the cause, results in increased microtubule stability in A. thaliana root. In addition, cell expansion does not only rely on cortical microtubule orientation but also plays a regulatory role in microtubule dynamics, as well. Various hypotheses may explain the increased cortical microtubule stability under decreased cell expansion such as the role of cell wall sensors and the presence of less dynamic cortical microtubules.

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In-Place FE Modeling of Unbonded Flexible Pipelines Capturing Pressure Stiffening and Decoupled Axial/Nonlinear Bending Stiffness

29th International Conference on Ocean, Offshore and Arctic Engineering: Volume 5, Parts A and B ◽

10.1115/omae2010-20014 ◽

2010 ◽

Author(s):

Edvin Hanken ◽

Evelyn R. Hollingsworth ◽

Lars S. Fagerland

Keyword(s):

Water Injection ◽

Bending Stiffness ◽

Axial Stiffness ◽

Fe Model ◽

Nonlinear Bending ◽

Upheaval Buckling ◽

History Effects ◽

System Integrity ◽

Non Linear ◽

Bending Behaviour

For fast track pipeline projects the need for costly installation vessels and sophisticated materials for rigid pipeline water injection systems, have made flexible pipelines a competitive alternative. They can be installed with less costly construction vessels, provide a competitive lead time and a corrosion resistant compliant material. Flexible pipelines have relative high axial stiffness and low non-linear bending stiffness which is a challenge to model correctly with FE for in-place analyses of pipelines. Whilst some FE programs can model the non-linear bending behaviour of a flexible pipeline at a given pressure, current FE tools do not include the effect of increased bending resistance as the system is pressurized. Therefore, a 3D FE model in ANSYS was developed to simulate the decoupled axial and nonlinear bending behaviour of a flexible, including the bend stiffening effect for increasing pressure. A description of the model is given in this paper. It will be demonstrated how the FE model can be used to simulate the 3D nonlinear catenary behaviour of an high pressure flexible pipeline tied into a manifold during pressurization. Due to high manifold hub loads during pressurization it is essential that such a model is capable of capturing all effects during pressurization to achieve an acceptable confidence level of the system integrity. It is also described how the FE model is used for upheaval buckling design, capturing non-linearities and load history effects that can reduce the conservatism in the design.

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The nature of reaction wood. IV. Variations in cell wall organization of tension wood fibres

Australian Journal of Botany ◽

10.1071/bt9550177 ◽

1955 ◽

Vol 3 (2) ◽

pp. 177 ◽

Cited By ~ 53

Author(s):

AB Wardrop ◽

HE Dadswell

Keyword(s):

Cell Wall ◽

Tension Wood ◽

Secondary Wall ◽

Degree Of Crystallinity ◽

Tropical Species ◽

Normal Wood ◽

Reaction Wood ◽

Gelatinous Layer ◽

Wood Fibres ◽

Cell Wall Organization

The cell wall organization, the cell wall texture, and the degree of lignification of tension wood fibres have been investigated in a wide variety of temperate and tropical species. Following earlier work describing the cell wall structure of tension wood fibres, two additional types of cell wall organization have been observed. In one of these, the inner thick "gelatinous" layer which is typical of tension wood fibres exists in addition to the normal three-layered structure of the secondary wall; in the other only the outer layer of the secondary wall and the thick gelatinous layer are present. In all the tension wood examined the micellar orientation in the inner gelatinous layer has been shown to be nearly axial and the cellulose of this layer found to be in a highly crystalline state. A general argument is presented as to the meaning of differences in the degree, of crystallinity of cellulose. The high degree of crystallinity of cellulose in tension wood as compared with normal wood is attributed to a greater degree of lateral order in the crystalline regions of tension wood, whereas the paracrystalline phase is similar in both cases. The degree of lignification in tension wood fibres has been shown to be extremely variable. However, where the degree of tension wood development is marked as revealed by the thickness of the gelatinous layer the lack of lignification is also most marked. Severity of tension wood formation and lack of lignification have also been correlated with the incidence of irreversible collapse in tension wood. Such collapse can occur even when no whole fibres are present, e.g. in thin cross sections. Microscopic examination of collapsed samples of tension wood has led to the conclusion that the appearance of collapse in specimens containing tendon wood can often be attributed in part to excessive shrinkage associated with the development of fissures between cells, although true collapse does also occur. Possible explanations of the irreversible shrinkage and collapse of tension wood fibres are advanced.

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