scholarly journals A Statistical Model of Cell Wall Dynamics during Expansive Growth

2018 ◽  
Author(s):  
S. Lalitha Sridhar ◽  
J.K.E. Ortega ◽  
F.J. Vernerey
Keyword(s):  
Cell Wall ◽  
Stress Relaxation ◽  
Statistical Approach ◽  
Turgor Pressure ◽  
Chara Corallina ◽  
Primary Cell Wall ◽  
Dimensionless Number ◽  
Phycomyces Blakesleeanus ◽  
Structural Support ◽  
Pressure Step

ABSTRACTExpansive growth is a process by which walled cells found in plants, algae and fungi, use turgor pressure to mediate irreversible wall deformation and regulate their shape and volume. The molecular structure of the primary cell wall must therefore be able to perform multiple function simultaneously such as providing structural support by a combining elastic and irreversible deformation and facilitate the deposition of new material during growth. This is accomplished by a network of microfibrils and tethers composed of complex polysaccharides and proteins that are able to dynamically mediate the network topology via constant detachment and reattachment events. Global biophysical models such as those of Lockhart and Ortega have provided crucial macroscopic understanding of the expansive growth process, but they lack the connection to molecular processes that trigger network rearrangements in the wall. In this context, we propose a statistical approach that describes the population behavior of tethers that have elastic properties and the ability to break and re-form in time. Tether properties such as bond lifetimes and stiffness, are then shown to govern global cell wall mechanics such as creep and stress relaxation. The model predictions are compared with experiments of stress relaxation and turgor pressure step-up from existing literature, for the growing cells of incised pea (Pisum sativus L.), algaeChara corallinaand the sporangiophores of the fungus,Phycomyces blakesleeanus. The molecular parameters are estimated from fits to experimental measurements combined with the information on the dimensionless number Πpethat is unique to each species. To our knowledge, this research is the first attempt to use a statistical approach to model the cell wall during expansive growth and we believe it will provide a better understanding of the cell wall dynamics at a molecular level.

scholarly journals Cell wall biosynthesis and the molecular mechanism of plant enlargement

2009 ◽  
Vol 36 (5) ◽  
pp. 383 ◽  
Author(s):  
John S. Boyer
Keyword(s):  
Cell Wall ◽  
Critical Level ◽  
Turgor Pressure ◽  
Chara Corallina ◽  
Wall Material ◽  
Primary Wall ◽  
Terrestrial Plants ◽  
Green Plants ◽  
Wall Deposition ◽  
Wall Growth

Recently discovered reactions allow the green alga Chara corallina (Klien ex. Willd., em. R.D.W.) to grow well without the benefit of xyloglucan or rhamnogalactan II in its cell wall. Growth rates are controlled by polygalacturonic acid (pectate) bound with calcium in the primary wall, and the reactions remove calcium from these bonds when new pectate is supplied. The removal appears to occur preferentially in bonds distorted by wall tension produced by the turgor pressure (P). The loss of calcium accelerates irreversible wall extension if P is above a critical level. The new pectate (now calcium pectate) then binds to the wall and decelerates wall extension, depositing new wall material on and within the old wall. Together, these reactions create a non-enzymatic but stoichiometric link between wall growth and wall deposition. In green plants, pectate is one of the most conserved components of the primary wall, and it is therefore proposed that the acceleration-deceleration-wall deposition reactions are of wide occurrence likely to underlie growth in virtually all green plants. C. corallina is one of the closest relatives of the progenitors of terrestrial plants, and this review focuses on the pectate reactions and how they may fit existing theories of plant growth.

scholarly journals Catalysts of plant cell wall loosening

F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 119 ◽  
Author(s):  
Daniel J. Cosgrove
Keyword(s):  
Cell Wall ◽  
Plant Cell Wall ◽  
Turgor Pressure ◽  
Wall Stress ◽  
Primary Cell Wall ◽  
Wall Structure ◽  
Xyloglucan Endotransglycosylase ◽  
Growing Cell ◽  
Tensile Forces ◽  
Wall Loosening

The growing cell wall in plants has conflicting requirements to be strong enough to withstand the high tensile forces generated by cell turgor pressure while selectively yielding to those forces to induce wall stress relaxation, leading to water uptake and polymer movements underlying cell wall expansion. In this article, I review emerging concepts of plant primary cell wall structure, the nature of wall extensibility and the action of expansins, family-9 and -12 endoglucanases, family-16 xyloglucan endotransglycosylase/hydrolase (XTH), and pectin methylesterases, and offer a critical assessment of their wall-loosening activity

scholarly journals Structure and Biomechanics during Xylem Vessel Transdifferentiation in Arabidopsis thaliana

Plants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1715
Author(s):  
Eleftheria Roumeli ◽  
Leah Ginsberg ◽  
Robin McDonald ◽  
Giada Spigolon ◽  
Rodinde Hendrickx ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Wall ◽  
Cell Walls ◽  
Turgor Pressure ◽  
Plant Cells ◽  
Building Blocks ◽  
Xylem Vessel ◽  
Primary Cell Wall ◽  
Individual Plant ◽  
Vessel Elements

Individual plant cells are the building blocks for all plantae and artificially constructed plant biomaterials, like biocomposites. Secondary cell walls (SCWs) are a key component for mediating mechanical strength and stiffness in both living vascular plants and biocomposite materials. In this paper, we study the structure and biomechanics of cultured plant cells during the cellular developmental stages associated with SCW formation. We use a model culture system that induces transdifferentiation of Arabidopsis thaliana cells to xylem vessel elements, upon treatment with dexamethasone (DEX). We group the transdifferentiation process into three distinct stages, based on morphological observations of the cell walls. The first stage includes cells with only a primary cell wall (PCW), the second covers cells that have formed a SCW, and the third stage includes cells with a ruptured tonoplast and partially or fully degraded PCW. We adopt a multi-scale approach to study the mechanical properties of cells in these three stages. We perform large-scale indentations with a micro-compression system in three different osmotic conditions. Atomic force microscopy (AFM) nanoscale indentations in water allow us to isolate the cell wall response. We propose a spring-based model to deconvolve the competing stiffness contributions from turgor pressure, PCW, SCW and cytoplasm in the stiffness of differentiating cells. Prior to triggering differentiation, cells in hypotonic pressure conditions are significantly stiffer than cells in isotonic or hypertonic conditions, highlighting the dominant role of turgor pressure. Plasmolyzed cells with a SCW reach similar levels of stiffness as cells with maximum turgor pressure. The stiffness of the PCW in all of these conditions is lower than the stiffness of the fully-formed SCW. Our results provide the first experimental characterization of the mechanics of SCW formation at single cell level.

scholarly journals NACL STRESS ALTERS PRIMARY CELL WALL TENSILE STRENGTH IN THE HALOPHYTIC GRASS, DISTICHLIS SPICATA L.

HortScience ◽  
1992 ◽  
Vol 27 (12) ◽  
pp. 1261c-1261
Author(s):  
Francisco Lopez-Gutierrez ◽  
Harrison G. Hughes ◽  
Nicholas C. Carpita
Keyword(s):  
Tensile Strength ◽  
Cell Wall ◽  
Cultured Cells ◽  
Turgor Pressure ◽  
Nacl Stress ◽  
Primary Cell ◽  
Cellulose Microfibrils ◽  
Distichlis Spicata ◽  
Primary Cell Wall ◽  
Stressed Cells

After 6 months of growth in 200,400, and 500 mm NaCl, cultured cells of Distichlis spicata showed a decreased cell volume (size) despite maintenance of turgor pressure sometimes 2-fold higher than that of the control. Tensile strength, as measured by a nitrogen gas decompression technique, showed empirically that the walls of NaCl-stressed cells were weaker than those of nonstressed cells. Breaking pressures of the walls of control cells were ≈68 ± 4 bars, while that of the walls of cells grown in 500 mm NaCl (-25 bars) were 14 ± 2 bars. The relative amount of cellulose per cell remained about constant despite salt stress. However, glucuronoarabinoxylans were more readily extractable, presumably because of a decrease in cross-linkage with phenol substances. Therefore, we suggest that cellulose microfibrils are not the only determinants that confer tensile strength to the primary cell wall, but rather subtle changes in the matrix polysaccharides are likely responsible for this event.

Measurements of the volumetric and transverse elastic extensibilities of Chara corallina internodes by combining the external force and pressure probe techniques

1982 ◽  
Vol 60 (8) ◽  
pp. 1503-1511 ◽  
Author(s):  
E. Steudle ◽  
J. M. Ferrier ◽  
J. Dainty
Keyword(s):  
Cell Wall ◽  
External Force ◽  
Plant Tissue ◽  
Turgor Pressure ◽  
Chara Corallina ◽  
Pressure Probe ◽  
Higher Plant ◽  
Concentrated Force ◽  
Simultaneous Application ◽  
Measuring Techniques

The transverse and volumetric elastic extensibilities of Chara corallina internodal cell wall tubes were studied by simultaneous application of the external force and pressure probe measuring techniques. It was found that there is a deformation of the cell wall resulting from the concentrated force exerted by the external force, which dominates the transverse extensibility at low turgor pressures, and which can be important at high turgor pressure. The implications of the effect for the use of the external force technique on higher plant tissue are discussed.

A fibre-reinforced fluid model of anisotropic plant cell growth

2010 ◽  
Vol 655 ◽  
pp. 472-503 ◽  
Author(s):  
R. J. DYSON ◽  
O. E. JENSEN
Keyword(s):  
Cell Wall ◽  
Cell Growth ◽  
Fluid Model ◽  
Turgor Pressure ◽  
Cellulose Microfibrils ◽  
Wall Material ◽  
Primary Cell Wall ◽  
Growing Cell ◽  
Asymptotic Reduction ◽  
Simple Sets

Many growing plant cells undergo rapid axial elongation with negligible radial expansion. Growth is driven by high internal turgor pressure causing viscous stretching of the cell wall, with embedded cellulose microfibrils providing the wall with strongly anisotropic properties. We present a theoretical model of a growing cell, representing the primary cell wall as a thin axisymmetric fibre-reinforced viscous sheet supported between rigid end plates. Asymptotic reduction of the governing equations, under simple sets of assumptions about the fibre and wall properties, yields variants of the traditional Lockhart equation, which relates the axial cell growth rate to the internal pressure. The model provides insights into the geometric and biomechanical parameters underlying bulk quantities such as wall extensibility, and shows how either dynamical changes in wall material properties or passive fibre reorientation may suppress cell elongation.

Sign in / Sign up

Export Citation Format

Share Document