Plant biology: Positive feedback between auxin and cell wall mechanics during apical hook formation

Structural and chemical deterioration and its impact on cell wall mechanics were investigated for visually intact cell walls (VICWs) in waterlogged archaeological wood (WAW). Cell wall mechanical properties were examined by nanoindentation without prior embedding. WAW showed more than 25% decrease of both hardness and elastic modulus. Changes of cell wall composition, cellulose crystallite structure and porosity were investigated by ATR-FTIR imaging, Raman imaging, wet chemistry, 13C-solid state NMR, pyrolysis-GC/MS, wide angle X-ray scattering, and N2 nitrogen adsorption. VICWs in WAW possessed a cleavage of carboxyl in side chains of xylan, a serious loss of polysaccharides, and a partial breakage of β-O-4 interlinks in lignin. This was accompanied by a higher amount of mesopores in cell walls. Even VICWs in WAW were severely deteriorated at the nanoscale with impact on mechanics, which has strong implications for the conservation of archaeological shipwrecks.

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Methods to quantify primary plant cell wall mechanics

Journal of Experimental Botany ◽

10.1093/jxb/erz281 ◽

2019 ◽

Vol 70 (14) ◽

pp. 3615-3648 ◽

Cited By ~ 15

Author(s):

Amir J Bidhendi ◽

Anja Geitmann

Keyword(s):

Cell Wall ◽

Plant Cell ◽

Plant Cell Wall ◽

Polymer Network ◽

Plant Cells ◽

Tensile Tests ◽

Mechanical Modeling ◽

Experimental Conditions ◽

Testing Techniques ◽

Cell Wall Mechanics

Abstract The primary plant cell wall is a dynamically regulated composite material of multiple biopolymers that forms a scaffold enclosing the plant cells. The mechanochemical make-up of this polymer network regulates growth, morphogenesis, and stability at the cell and tissue scales. To understand the dynamics of cell wall mechanics, and how it correlates with cellular activities, several experimental frameworks have been deployed in recent years to quantify the mechanical properties of plant cells and tissues. Here we critically review the application of biomechanical tool sets pertinent to plant cell mechanics and outline some of their findings, relevance, and limitations. We also discuss methods that are less explored but hold great potential for the field, including multiscale in silico mechanical modeling that will enable a unified understanding of the mechanical behavior across the scales. Our overview reveals significant differences between the results of different mechanical testing techniques on plant material. Specifically, indentation techniques seem to consistently report lower values compared with tensile tests. Such differences may in part be due to inherent differences among the technical approaches and consequently the wall properties that they measure, and partly due to differences between experimental conditions.

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Brassinosteroids Influence Arabidopsis Hypocotyl Graviresponses through Changes in Mannans and Cellulose

Plant and Cell Physiology ◽

10.1093/pcp/pcab024 ◽

2021 ◽

Author(s):

Marc Somssich ◽

Filip Vandenbussche ◽

Alexander Ivakov ◽

Norma Funke ◽

Colin Ruprecht ◽

...

Keyword(s):

Cell Wall ◽

Cellulose Fibre ◽

Soil Surface ◽

Cellular Growth ◽

Upright Posture ◽

Cellulose Fibres ◽

Negative Effect ◽

Biochemical Analyses ◽

Plant Shoots ◽

Cell Wall Mechanics

Abstract The force of gravity is a constant environmental factor. Plant shoots respond to gravity through negative gravitropism and gravity resistance. These responses are essential for plants to direct the growth of aerial organs away from the soil surface after germination and to keep an upright posture above ground. We took advantage of the effect of brassinosteroids (BRs) on the two types of graviresponses in Arabidopsis thaliana hypocotyls to disentangle functions of cell wall polymers during etiolated shoot growth. The ability of etiolated Arabidopsis seedlings to grow upward was suppressed in the presence of 24-epibrassinolide (EBL) but enhanced in the presence of brassinazole (BRZ), an inhibitor of BR biosynthesis. These effects were accompanied by changes in cell wall mechanics and composition. Cell wall biochemical analyses, confocal microscopy of the cellulose-specific pontamine S4B dye and cellular growth analyses revealed that the EBL and BRZ treatments correlated with changes in cellulose fibre organization, cell expansion at the hypocotyl base and mannan content. Indeed, a longitudinal reorientation of cellulose fibres and growth inhibition at the base of hypocotyls supported their upright posture whereas the presence of mannans reduced gravitropic bending. The negative effect of mannans on gravitropism is a new function for this class of hemicelluloses. We also found that EBL interferes with upright growth of hypocotyls through their uneven thickening at the base.

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Interplay between Cell Wall and Auxin Mediates the Control of Differential Cell Elongation during Apical Hook Development

Current Biology ◽

10.1016/j.cub.2020.02.055 ◽

2020 ◽

Vol 30 (9) ◽

pp. 1733-1739.e3 ◽

Cited By ~ 4

Author(s):

Bibek Aryal ◽

Kristoffer Jonsson ◽

Anirban Baral ◽

Gloria Sancho-Andres ◽

Anne-Lise Routier- Kierzkowska ◽

...

Keyword(s):

Cell Wall ◽

Cell Elongation ◽

Apical Hook ◽

Differential Cell

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Role of Golgi Apparatus in the Formation of Plant Slimes, Cuticles and Extraneous Wall Material

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100050445 ◽

1974 ◽

Vol 32 ◽

pp. 86-87

Author(s):

Hilton H. Mollenhauer

Keyword(s):

Cell Wall ◽

Golgi Apparatus ◽

Cell Walls ◽

Growth And Development ◽

Characteristic Property ◽

Plant Cells ◽

Plant Biology ◽

Wall Material ◽

Wall Properties

Cell walls are fundamentally involved in many aspects of plant biology including the morphology, growth, and development of plant cells and the interactions between plant hosts and their pathogens. Intuitively, one can recognize that these wall properties result from the sum total of the various components of which the wall is composed and that there are classes of substances each of which impart a characteristic property to the cell wall.

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