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Full-Text Articles in Cell and Developmental Biology
Geometric Constraints And The Anatomical Interpretation Of Twisted Plant Organ Phenotypes, Renate Weizbauer, Winfried S. Peters, Burkhard Schulz
Geometric Constraints And The Anatomical Interpretation Of Twisted Plant Organ Phenotypes, Renate Weizbauer, Winfried S. Peters, Burkhard Schulz
Winfried S. Peters
The study of plant mutants with twisting growth in axial organs, which normally grow straight in the wild-type, is expected to improve our understanding of the interplay among microtubules, cellulose biosynthesis, cell wall structure, and organ biomechanics that control organ growth and morphogenesis. However, geometric constraints based on symplastic growth and the consequences of these geometric constraints concerning interpretations of twisted-organ phenotypes are currently underestimated. Symplastic growth, a fundamental concept in plant developmental biology, is characterized by coordinated growth of adjacent cells based on their connectivity through cell walls. This growth behavior implies that in twisting axial organs, all cell …
My Embarrassment At Not Knowing Heinich, Winfried S. Peters
My Embarrassment At Not Knowing Heinich, Winfried S. Peters
Winfried S. Peters
This paper has no abstract; this is the first paragraph. The mechanisms of tissue tension phenomena and their physiological significance are controversial (Vincent and Jeronimidis, 1991; [Peters and Tomos, 1996a] and [Peters and Tomos, 1996b]; Kutschera and Niklas, 2007). Specifically, the apparently spontaneous expansion of inner tissues after removal of the peripheral cell layers is a perpetual bone of contention. We had reported evidence suggesting that inner tissue expansion is driven by water uptake (Peters and Tomos, 2000). Kutschera and Niklas (2007) rejected this interpretation and insisted that inner tissue expansion is an elastic response to the release from compressive …
Tailor-Made Composite Functions As Tools In Model Choice: The Case Of Sigmoidal Vs Bi-Linear Growth Profiles, Winfried Peters, Tobias Baskin
Tailor-Made Composite Functions As Tools In Model Choice: The Case Of Sigmoidal Vs Bi-Linear Growth Profiles, Winfried Peters, Tobias Baskin
Winfried S. Peters
Background Roots are the classical model system to study the organization and dynamics of organ growth zones. Profiles of the velocity of root elements relative to the apex have generally been considered to be sigmoidal. However, recent high-resolution measurements have yielded bi-linear profiles, suggesting that sigmoidal profiles may be artifacts caused by insufficient spatio-temporal resolution. The decision whether an empirical velocity profile follows a sigmoidal or bi-linear distribution has consequences for the interpretation of the underlying biological processes. However, distinguishing between sigmoidal and bi-linear curves is notoriously problematic. A mathematical function that can describe both types of curve equally well …
Growth Rate Gradients And Extracellular Ph In Roots: How To Control An Explosion, Winfried S. Peters
Growth Rate Gradients And Extracellular Ph In Roots: How To Control An Explosion, Winfried S. Peters
Winfried S. Peters
This paper has no abstract; this is the first paragraph. As plant growth is restricted to defined zones of growing organs, the methodologically consistent analysis of spatial growth rate patterns in organ growth zones is prerequisite for studies into the regulation of cell growth in situ (Silk, 1984). The elongation zones at the tips of growing roots are classical objects of kinematic growth analysis, which aims at the quantitative description of growth rate gradients (Erickson & Sax, 1956). Root growth zones were generally believed to be characterized by growth rates that change gradually along bell-shaped growth gradients (Erickson & Sax, …
The Biophysics Of Leaf Growth In Salt-Stressed Barley. A Study At The Cell Level., Wieland Fricke, Winfried Peters
The Biophysics Of Leaf Growth In Salt-Stressed Barley. A Study At The Cell Level., Wieland Fricke, Winfried Peters
Winfried S. Peters
Biophysical parameters potentially involved in growth regulation were studied at the single-cell level in the third leaf of barley (Hordeum vulgare) after exposure to various degrees of NaCl stress for 3 to 5 d. Gradients of elongation growth were measured, and turgor pressure, osmolality, and water potentials (ψ) were determined (pressure probe and picoliter osmometry) in epidermal cells of the elongation zone and the mature blade. Cells in the elongation zone adjusted to decreasing external ψ through increases in cell osmolality that were accomplished by increased solute loads and reduced water contents. Cell turgor changed only slightly. In …
Does Growth Correlate With Turgor-Induced Elastic Strain In Stems? A Re-Evaluation Of De Vries' Classical Experiments, Winfried Peters, Maggie Farm, A. Kopf
Does Growth Correlate With Turgor-Induced Elastic Strain In Stems? A Re-Evaluation Of De Vries' Classical Experiments, Winfried Peters, Maggie Farm, A. Kopf
Winfried S. Peters
The correlation between growth and turgor-induced elastic expansion was studied in hypocotyls of sunflower (Helianthus annuus) seedlings under various growth conditions. Turgor-induced elastic cell wall strain was greater in hypocotyls of faster growing seedlings, i.e. in etiolated versus light-grown ones. It also was higher in rapidly growing young seedlings as compared with nongrowing mature ones. However, analysis of the spatial distribution of elastic strain and growth demonstrated that their correspondence was only apparent. Profiles of elastic strain declined steadily from the top of the hypocotyls toward the basis, whereas the profiles of relative elemental growth rate along the …
The Mechanic State Of “Inner Tissue” In The Growing Zone Of Sunflower Hypocotyls And The Regulation Of Its Growth Rate Following Excision, Winfried Peters, A. Tomos
The Mechanic State Of “Inner Tissue” In The Growing Zone Of Sunflower Hypocotyls And The Regulation Of Its Growth Rate Following Excision, Winfried Peters, A. Tomos
Winfried S. Peters
Spontaneous growth of isolated inner tissue from the etiolated sunflower (Helianthus annuus L.) hypocotyl growing zone was investigated. A new preparation technique allowed measurements starting 3 s after excision. Elongation with respect to the turgescent and plasmolized state was quantified in terms of relative growth rates, facilitating comparison to growth in situ. Turgor and turgor-induced strain were determined. Overall longitudinal strain in inner tissues in situ was positive, indicating that compressive forces exerted by peripheral tissues are outweighed by turgor-dependent tensile stress. Inner tissue expansion following isolation depended on water uptake. Extreme plastic extension rates occurred immediately after excision, …
What Makes Plants Different? Principles Of Extracellular Matrix Function In 'Soft' Plant Tissues [Review Article], Winfried Peters, Wolfgang Hagemann, A. Tomos
What Makes Plants Different? Principles Of Extracellular Matrix Function In 'Soft' Plant Tissues [Review Article], Winfried Peters, Wolfgang Hagemann, A. Tomos
Winfried S. Peters
An overview of the biomechanic and morphogenetic function of the plant extracellular matrix (ECM) in its primary state is given. ECMs can play a pivotal role in cellular osmo- and volume-regulation, if they enclose the cell hermetically and constrain hydrostatic pressure evoked by osmotic gradients between the cell and its environment. From an engineering viewpoint, such cell walls turn cells into hydraulic machines, which establishes a crucial functional differences between cell walls and other cellular surface structures. Examples of such hydraulic machineries are discussed. The function of cell walls in the control of pressure, volume, and shape establishes constructional evolutionary …
The Correlation Of Profiles Of Surface Ph And Elongation Growth In Maize Roots, Winfried Peters, Hubert Felle
The Correlation Of Profiles Of Surface Ph And Elongation Growth In Maize Roots, Winfried Peters, Hubert Felle
Winfried S. Peters
High-resolution profiles of surface pH and growth along vertically growing maize (Zea mays) primary root tips were determined simultaneously by pH-sensitive microelectrodes and marking experiments. Methodological tests were carried out that proved the reliability of our kinematic growth analysis, while questioning the validity of an alternative technique employed previously. A distal acidic zone around the meristematic region and a proximal one around the elongation zone proper were detected. This pattern as such persisted irrespective of the bulk pH value. The proximal acidic region coincided with maximum relative elemental growth rates (REGR), and both characters reacted in a correlated …
Xet-Related Genes And Growth Kinematics In Barley Leaves, Winfried Peters, Wieland Fricke, Peter Chandler
Xet-Related Genes And Growth Kinematics In Barley Leaves, Winfried Peters, Wieland Fricke, Peter Chandler
Winfried S. Peters
Recently Schünmann et al. (1997; Plant, Cell and Environment 20, 1439–1450) investigated the correlation of spatial patterns of xyloglucan-endotransglycosylase (XET) activity, XET-related mRNAs, and growth in elongating barley (Hordeum vulgare L.) leaves. Here, methodological difficulties in the kinematic growth analysis are discussed, and it is concluded that the role that XET-related gene activity plays in the control of spatial growth patterns remains undetermined.
The Temporal Correlation Of Changes In Apoplast Ph And Growth Rate In Maize Coleoptile Segments, Winfried Peters, Hartwig Lüthen, Michael Böttger, Hubert Felle
The Temporal Correlation Of Changes In Apoplast Ph And Growth Rate In Maize Coleoptile Segments, Winfried Peters, Hartwig Lüthen, Michael Böttger, Hubert Felle
Winfried S. Peters
Auxin induces extracellular acidification in growing shoot tissue. The causal relationship between this process and auxin-mediated growth is debated, partly because of contradicting previous reports on the temporal correlation of auxin-induced apoplast pH-drops and growth bursts. We have simultaneously measured both parameters on the background of spontaneously occurring endogenous changes in growth rate and apoplast pH in maize coleoptile segments. Our data demonstrate good temporal correlation, during both the ‘Spontaneous Growth Response’ and the response to exogenous auxin, which is transient under the conditions chosen due to rapid auxin metabolism. We suggest that cell wall pH and growth rate are …
Wounding-Induced Cell Wall Ph Shifts In Coleoptile Segments Of Various Poaceae, Winfried Peters
Wounding-Induced Cell Wall Ph Shifts In Coleoptile Segments Of Various Poaceae, Winfried Peters
Winfried S. Peters
Wounding-induced extracellular pH shifts were characterized previously in excised segments of maize (Zea mays L.) coleoptiles. In the present study it is demonstrated that similar pH shifts also occur in Triticum aestivum L., Secale cereale L., Hordeum vulgare L., Avena sativa L., Sorghum durra (Forsk.) Stapf, and Setaria italica (L.) Beauv., with characteristic quantitative differences between the species. Indole-acetic acid induces pronounced drops of the medium pH in all species except Setaria italica.
Iaa Breakdown And Its Effect On Auxin-Induced Cell Wall Acidification In Maize Coleoptile Segments, Winfried Peters, Christa Lommel, Hubert Felle
Iaa Breakdown And Its Effect On Auxin-Induced Cell Wall Acidification In Maize Coleoptile Segments, Winfried Peters, Christa Lommel, Hubert Felle
Winfried S. Peters
In excised Zea mays L. coleoptiles incubated in aerated media at high fresh weight per volume ratios, indole-3-acetic acid induces transient drops of extracellular pH. Based on the quantitative dependency of the response on the initial auxin concentration we developed a novel auxin bioassay, which allows reliable estimation of IAA concentrations between 10−8.5 and 10−5 M. Using the bioassay and complementary concentration measurements by IAA fluorescence we found the transient IAA-induced pH response paralleled by a decrease of auxin activity and concentration in the medium. This decline is rapid and starts immediately upon auxin addition, and insofar differs from the …
The Determination Of Relative Elemental Growth Rate Profiles From Segmental Growth Rates (A Methodological Evaluation), Winfried Peters, Nirit Bernstein
The Determination Of Relative Elemental Growth Rate Profiles From Segmental Growth Rates (A Methodological Evaluation), Winfried Peters, Nirit Bernstein
Winfried S. Peters
Relative elemental growth rate (REGR) profiles describe spatial patterns of growth intensity; they are indispensable for causal growth analyses. Published methods of REGR profile determination from marking experiments fall in two classes: the profile is either described by a series of segmental growth rates, or calculated as the slope of a function describing the displacement velocities of points along the organ. The latter technique is usually considered superior for theoretical reasons, but to our knowledge, no comparative methodological study of the two approaches is currently available. We formulated a model REGR profile that resembles those reported from primary roots. We …
The Epidermis Still In Control?, Winfried Peters, A. Tomos
The Epidermis Still In Control?, Winfried Peters, A. Tomos
Winfried S. Peters
This paper has no abstract; these are the first two paragraphs. The search for a molecular mechanism of auxin action has rendered the “Auxin-Binding-Protein 1” (ABP-1) the top candidate for a functional auxin receptor (Venis and Napier, 1995), although its status remains disputed (Jones, 1994; Hertel, 1995; Napier, 1995; Venis, 1995). ABP-1 had long been thought to be localized exclusively in epidermal cells in coleoptiles (Löbler and Klämbt, 1985), and thus had fitted nicely the “epidermal-growth-control-hypothesis” (Kutschera, 1987, 1992). The recent report from the same lab of its uniform distribution throughout the coleoptile (Kayser and Klämbt, 1995) not only rises …
The History Of Tissue Tension, Winfried S. Peters, A. Deri Tomos
The History Of Tissue Tension, Winfried S. Peters, A. Deri Tomos
Winfried S. Peters
In recent years the phenomenon of tissue tension and its functional connection to elongation growth has regained much interest. In the present study we reconstruct older models of mechanical inhomogenities in growing plant organs, in order to establish an accurate historical background for the current discussion. We focus on the iatromechanic model developed in Stephen Hales' Vegetable Staticks, Wilhelm Hofmeister's mechanical model of negative geotropism, Julius Sachs' explanation of the development of tissue tension, and the differential-auxin-response-hypothesis by Kenneth Thimann and Charles Schneider. Each of these models is considered in the context of its respective historic and theoretical environment. …
Auxin-Induced H+-Pump Stimulation Does Not Depend On The Presence Of Epidermal Cells In Corn Coleoptiles, Winfried Peters, Ursula Richter, Hubert Felle
Auxin-Induced H+-Pump Stimulation Does Not Depend On The Presence Of Epidermal Cells In Corn Coleoptiles, Winfried Peters, Ursula Richter, Hubert Felle
Winfried S. Peters
Cell-wall acidification and electrical reactions (depolarization and hyperpolarization) are typical auxin responses in maize (Zea mays L.) coleoptiles. In an attempt to test the role of the outer epidermis in these responses, they have been measured and compared in intact and peeled coleoptile fragments. To exclude interactions between parenchymal and epidermal cells, the coleoptile pieces were completely stripped of their outer epidermis. This preparation was monitored by means of a scanning electron microscope. When externally applied indole-3-acetic acid was tested, we found that neither cell-wall acidification nor the electrical membrane responses depended on the presence of intact epidermal cells.
The Electrical Response Of Maize To Auxin, Hubert Felle, Winfried Peters, Klaus Palme
The Electrical Response Of Maize To Auxin, Hubert Felle, Winfried Peters, Klaus Palme
Winfried S. Peters
The electrical response of Zea mays coleoptiles and suspension cultured cells to several growth-promoting auxins (IAA, IBA, 2,4-D, 2,4,5-T, 1-NAA) and some of their structural analogues (2,3-D, 2-NAA) has been tested. In coleoptiles two typical electrical responses to IAA are observed: an immediate rapid depolarization, and a hyperpolarization following 7–10 minutes after the first external addition of IAA. Of the other tested compounds only 1-NAA significantly depolarized the cells, whereas all auxins as well as the analogues evoked delayed hyperpolarizations. In contrast, the suspension cells were not hyperpolarized by any of the tested compounds, but were strongly depolarized by IAA, …
Control Of Apoplast Ph In Corn Coleoptile Segments. I: The Endogenous Regulation Of Cell Wall Ph, Winfried Peters, Hubert Felle
Control Of Apoplast Ph In Corn Coleoptile Segments. I: The Endogenous Regulation Of Cell Wall Ph, Winfried Peters, Hubert Felle
Winfried S. Peters
The endogenous control of cell wall pH of Zea mays L. coleoptiles has been investigated using abraded as well as non-abraded segments. Regardless of the initial medium pH, coleoptile segments characteristically change the external pH: after about 2 h a pH maximum (neutral peak; NP) around 6 is reached, followed by a slow pH decrease that levels off in a steady state at 4.8 after 7 h (acid equilibrium; AE). This basic behavior is independent of medium composition, but critically requires O2; it is not altered when the number of coleoptiles per volume is increased to over 10 col./mL. Thus, …
Control Of Apoplast Ph In Corn Coleoptile Segments. Ii: The Effects Of Various Auxins And Auxin Analogues, Winfried Peters, Hubert Felle
Control Of Apoplast Ph In Corn Coleoptile Segments. Ii: The Effects Of Various Auxins And Auxin Analogues, Winfried Peters, Hubert Felle
Winfried S. Peters
Using abraded Zea mays L. coleoptile segments, proton extrusion has been measured in the presence of growth promoting auxins and their inactive structural analogues. Prior to application, the segments spontaneously acidified the external medium to pH 4.8 within 7 h. Indole-3-acetic acid (IAA) concentration dependently decreases external pH to 4.2, fusicoccin (FC) to below 3.5. Whereas the IAA-effect spontaneously recovers and can be repeated, the FC-effect is final and irreversible. The growth promoting auxins 2,4-dichlorophenoxyacetic acid (2,4-D), 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), indole-3-butyric acid (IBA) and 1-naphthylacetic acid (1-NAA) all stimulate proton extrusion similar to IAA. The growth inactive structural analogues 2,3-dichlorophenoxyacetic …