Growth Physics in <i>Nitella</i>: a Method for Continuous <i>in Vivo</i> Analysis of Extensibility Based on a Micro-manometer Technique for Turgor Pressure

Green, Paul B.

doi:10.1104/pp.43.8.1169

Cited by 135 publications

(92 citation statements)

References 30 publications

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“…Since the rate of cell enlargement is dependent on its gross extensibility and turgidity status' (Green, 1968;Hsiao, 1973) and the cell turgidity status in those water-stressed fruits is the same as in the control ones during the poststress period, it is possible to suggest that cell extensibility would be increased. This effect may be due to the violent changes of water status in the cells, from a good turgidity status to an important water deficit, or inversely during the period of water stress or at the moment of water stress removal.…”

Section: Discussionmentioning

confidence: 99%

Response of peach tree growth and cropping to soil water deficit at various phenological stages of fruit development

Li¹,

Huguet²,

Schoch³

et al. 1989

Journal of Horticultural Science

136

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SUMMARYFour-and five-year-old 'Merrill Sunda~ce' peach trees, protected from rainfall by polyethylene film covers, were fully irrigated using micro-sprinkler (irrigatio~scheduling based on a tensiometer technique), or subjected to water stress at different phenological stages of fruit growth. Water deficit imposed during the first phase of rapid growth significantly increased fruit size at harvest during two experimental years when compared with the control full-irrigation treatment, while smaller fruits were produced from trees receiving an imposed water deficit during the final accelerated fruit growth, or throughout the fruit development period. When water deficit was applied to the trees during the pit hardening phase and the first two phases of fruit development, fruit size was not affected. However, shoot extension growth and limb diameter increases were limited whenever water supply was restricted. After-effects on limb expansion growth and benefits of water stress on fruit growth were obvious during the post-stress period. Moreover, premature fruit drops after the June-drop were reduced for all the water stress treatments. The level of total soluble solids was higher in fruits from the trees subjected to water stress during the final rapid phase of fruit growth, and flower bud production was improved on trees given a restricted supply of water during the critical period of flower bud induction.

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Section: Discussionmentioning

confidence: 99%

Response of peach tree growth and cropping to soil water deficit at various phenological stages of fruit development

Li¹,

Huguet²,

Schoch³

et al. 1989

Journal of Horticultural Science

136

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“…Since the internode is cylindrical, the longitudinal force on the wall in vivo is approximated from the equation F = Pirr2, where P is the turgor pressure and r is the cell radius. Turgor pressure was taken as 5 bars (50 MPa) (15) and the radius was measured by means of a microscope equipped with an ocular micrometer.…”

Section: Methodsmentioning

confidence: 99%

Cell wall extension in Nitella as influenced by acids and ions.

Métraux¹,

Taiz²

1977

Proc. Natl. Acad. Sci. U.S.A.

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The giant internode cells of Nitella axillaris exhibit acid-induced growth similar to that found in higher plants. The threshold pH is 4.5, with a maximum at 3.5. The acid growth effect is transient, lasting no more than 32 min. Extensibility measurements of isolated cell walls showed a similar pattern of acid enhancement. Prolonged boiling in water (12 hr) only partially inhibited the acid-induced wall extensibility and actually increased the extensibility at pH 6. It was concluded that physical, rather than enzymatic, processes were responsible for acid-enhanced continuous extension ("creep") in Nitella walls. A complex cation-sensitive mechanism that affects extensibility was also characterized. Among the stimulatory (wall-softening) cations, divalents were generally more effective than monovalents, with magnesium being the most stimulatory. The inhibitory (wall-hardening) cations included divalents and trivalents, aluminum being the most inhibitory. Ionic effects on extensibility were even less sensitive to prolonged boiling in water than acid effects.

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“…For bacterial, plant, and fungal cells, growth requires both the synthesis of cytoplasmic components and the expansion of the cell wall, a stiff polymeric network that encloses these cells. It is well established that plant cells use turgor pressure, the outward normal force exerted by the cytoplasm on the cell wall, to drive mechanical expansion of the cell wall during growth (1,2). In contrast, our understanding of the physical mechanisms of cell-wall expansion in bacteria is limited.…”

mentioning

confidence: 99%

Response of Escherichia coli growth rate to osmotic shock

Rojas

Theriot

Huang

2014

Proc. Natl. Acad. Sci. U.S.A.

187

188

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It has long been proposed that turgor pressure plays an essential role during bacterial growth by driving mechanical expansion of the cell wall. This hypothesis is based on analogy to plant cells, for which this mechanism has been established, and on experiments in which the growth rate of bacterial cultures was observed to decrease as the osmolarity of the growth medium was increased. To distinguish the effect of turgor pressure from pressure-independent effects that osmolarity might have on cell growth, we monitored the elongation of single Escherichia coli cells while rapidly changing the osmolarity of their media. By plasmolyzing cells, we found that cell-wall elastic strain did not scale with growth rate, suggesting that pressure does not drive cell-wall expansion. Furthermore, in response to hyper-and hypoosmotic shock, E. coli cells resumed their preshock growth rate and relaxed to their steady-state rate after several minutes, demonstrating that osmolarity modulates growth rate slowly, independently of pressure. Oscillatory hyperosmotic shock revealed that although plasmolysis slowed cell elongation, the cells nevertheless "stored" growth such that once turgor was reestablished the cells elongated to the length that they would have attained had they never been plasmolyzed. Finally, MreB dynamics were unaffected by osmotic shock. These results reveal the simple nature of E. coli cell-wall expansion: that the rate of expansion is determined by the rate of peptidoglycan insertion and insertion is not directly dependent on turgor pressure, but that pressure does play a basic role whereby it enables full extension of recently inserted peptidoglycan.bacterial morphogenesis | cell mechanics C ell growth is the result of a complex system of biochemical processes and mechanical forces. For bacterial, plant, and fungal cells, growth requires both the synthesis of cytoplasmic components and the expansion of the cell wall, a stiff polymeric network that encloses these cells. It is well established that plant cells use turgor pressure, the outward normal force exerted by the cytoplasm on the cell wall, to drive mechanical expansion of the cell wall during growth (1, 2). In contrast, our understanding of the physical mechanisms of cell-wall expansion in bacteria is limited. Furthermore, the bacterial cell wall is distinct from its eukaryotic counterparts in both ultrastructure and chemical composition. In particular, the peptidoglycan cell wall of Gram-negative bacteria is extremely thin, comprising perhaps a molecular monolayer (3). This raises the question of whether these organisms require turgor pressure for cell-wall expansion, or whether they use a different strategy than organisms with thicker walls.Turgor pressure is established within cells according to the Morse equation, P = RTðC in − C out Þ, where C in is the osmolarity of the cytoplasm, C out is the osmolarity of the extracellular medium, R is the gas constant, and T is the temperature. In the Gram-negative bacterium Escherichia coli, P has been estimate...

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Growth Physics in Nitella: a Method for Continuous in Vivo Analysis of Extensibility Based on a Micro-manometer Technique for Turgor Pressure

Cited by 135 publications

References 30 publications

Response of peach tree growth and cropping to soil water deficit at various phenological stages of fruit development

Response of peach tree growth and cropping to soil water deficit at various phenological stages of fruit development

Cell wall extension in Nitella as influenced by acids and ions.

Response of Escherichia coli growth rate to osmotic shock

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