Plasmolysis: Loss of Turgor and Beyond

Abstract

Plasmolysis is a typical response of plant cells exposed to hyperosmotic stress. The loss of turgor causes the violent detachment of the living protoplast from the cell wall. The plasmolytic process is mainly driven by the vacuole. Plasmolysis is reversible (deplasmolysis) and characteristic to living plant cells. Obviously, dramatic structural changes are required to fulfill a plasmolytic cycle. In the present paper, the fate of cortical microtubules and actin microfilaments is documented throughout a plasmolytic cycle in living cells of green fluorescent protein (GFP) tagged Arabidopsis lines. While the microtubules became wavy and highly bundled during plasmolysis, cortical filamentous actin remained in close vicinity to the plasma membrane lining the sites of concave plasmolysis and adjusting readily to the diminished size of the protoplast. During deplasmolysis, cortical microtubule re-organization progressed slowly and required up to 24 h to complete the restoration of the original pre-plasmolytic pattern. Actin microfilaments, again, recovered faster and organelle movement remained intact throughout the whole process. In summary, the hydrostatic skeleton resulting from the osmotic state of the plant vacuole “overrules” the stabilization by cortical cytoskeletal elements.

Impact of drying methods on the changes of fruit microstructure unveiled by X-ray micro-computed tomography

“…The loss of water is accompanied by shrinkage of the bulk tissue 13 and changes in microstructure, including cell collapse, cell shrinkage, cell membrane detachment (plasmolysis) or cell membrane breakage (lysis). [14][15][16] These changes strongly inuence the moisture transport properties of the tissue 17 and also induce variations in the nal product quality. The product texture is inuenced for example by the bulk density, porosity, cell size, cell shape and cell wall thickness of the dried product.…”

New insights into the apple fruit dehydration process at the cellular scale by 3D continuum modeling

“…Water loss beyond the zero turgor point induces several responses depending on the initial shape and size of the cell, the viscosity of the protoplast and the environmental conditions (Oparka 1994). There are three typical dehydration responses of a fruit cell after losing its turgor pressure (condition III in Figure 2) (Seguí et al 2010;Lang et al 2014). The first response is free shrinkage (condition IIIa in Figure 2), which means that the cell and protoplast can continue to shrink in an unrestricted way.…”

The cell wall of Arabidopsis thaliana influences actin network dynamics

“…Komis et al (2002) thought that actin bundles mitigate the physical stresses caused by the deformation of the plasma membrane. Wojtaszek et al (2007) and Lang et al (2014) compared these bundle structures to the stress fibres found in animal cells; they, and Komis et al (2002), suggest that the bundles are involved in maintaining the shape and regulating volume of the protoplast during plasmolysis. The mechanical properties of these 'stress fibre-like' actin bundles will be dependent on the proteins that cross-link the filaments: how tightly they bind them together and how much sliding can occur (Blanchoin et al, 2014).…”

“…Lang et al (2014) monitored the actin cytoskeleton during the onset of plasmolysis and reported that actin filaments reorganise rapidly and when the cell was fully plasmolysed they observed many actin bundles. This suggests that as the protoplasm separates from the cell wall the actin cytoskeleton rapidly alters in structure, forming bundles that become stable as the cell becomes fully plasmolysed.…”