Turgor, temperature and the growth of plant cells: using Chara corallina as a model system

Abstract

Rapid changes in turgor pressure (P:) and temperature (T:) are giving new information about the mechanisms of plant growth. In the present work, single internode cells of the large-celled alga Chara corallina were used as a model for plant growth. P was changed without altering the chemical environment of the wall while observing growth without elastic changes. When P: was measured before any changes, the original growth rate bore no relationship to the original P. However, if P of growing cells was decreased, growth responded immediately without evidence for rapid changes in wall physical properties. Growth occurred only above a 0.3 MPa threshold, and increasing P caused small increases in growth that became progressively larger as P rose, resulting in a curvilinear response overall. The small changes in growth close to the threshold may explain early failures to detect these responses. When T was lowered, the elastic properties of the cell were unaffected, but growth was immediately inhibited. The lower T caused P to decrease, but returning P to its original value did not return growth to its original rate. The decreased P at low T occurred because of T effects on the osmotic potential of the cell. At above-normal P, growth partially resumed at low T Therefore, growth required a P-sensitive process that was also T-sensitive. Because elastic properties were little affected by T, but growth was markedly affected, the process is likely to involve metabolism. The rapidity of its response to P and T probably excludes the participation of changes in gene expression.

A finite strain fibre-reinforced viscoelasto-viscoplastic model of plant cell wall growth

“…This is estimated by using Young's modulus of single cellulose microfibrils, 150.0 GPa [4], and assuming the volume fraction of microfibrils to be about 1%-3%. The value of 0  is around several 11 10 Pa s  , estimated from the experimental data of growth (curves of rate of elongation vs time, which were reported by Proseus and co-workers [16][66] [69]) by using the method suggested in our previous work [51]. In this case, the cell solution was injected using a pressure probe to increase P by 0.04 MPa in 10 seconds.…”

“…Fig. 10(b) and (c) together with the corresponding experimental data ( [69], Fig. 3b and 3c) for comparison.…”

“…The viscoelastic and irreversible responses of cell walls interplaying with turgor pressure and temperature reported by Proseus et al [66], Proseus et al [69] and Proseus and Boyer [16] are modelled in the case studies. To the authors' knowledge, this is the first time that all responses can be covered by a single model.…”

“…The inelastic response which is obtained by subtracting the deformation at 3.1 C from that at 24 C , is shown in Fig. 10(d) together with the corresponding experimental data ( [69], Fig. 3d).…”

Actuation systems in plants as prototypes for bioinspired devices

“…The reduction in turgor pressure results in a cellular water uptake, which finally causes the expansion of the cell. Lockhart (1965) was one of the first to describe this interrelation of wall expansion and water uptake in a biophysical model, which was the basis for further approaches to take cell wall properties and the influence of water flow into account (Sellen 1983;Cosgrove 1993;Veytsman & Cosgrove 1998;Proseus et al 1999Proseus et al , 2000.…”