Cytorrhysis

Schematic of typical plant cell

Cytorrhysis is complete collapse of a plant cell wall due to the loss of internal positive pressure (hydraulic turgor pressure), which is needed to maintain the upright structure of the cell wall.^[1] This occurs when water continues to diffuse out of the cell after the point of zero turgor pressure has been reached when the ability of the plant cell to regulate turgor pressure is compromised such as during times of intense drought or when the concentration of solutes in the root media is very high.^[2] Freezing cytorrhysis can also be observed under freezing conditions.^[3]

Although the cell wall is not actually destroyed, the vacuole seems to increase in size and finally collapses, releasing its components into the cytosol. This is because as the cell size is decreasing it would need to increase its surface area. In order to do that vacuole expands and eventually bursts. The plasma membrane seems to be squashed against the cell wall.

Cytorrhysis occurs when the size of the molecules constituting the osmoticum exceeds that of the pores of the cell wall matrix.

It has being filed as a major reason for the depletion of plants in many sub-tropical forests.

Notes

1. {{"3.1.4 - Turgor Loss, Cytorrhysis, and Plasmolysis." 3.1.4 - Turgor Loss, Cytorrhysis, and Plasmolysis. Australian Society of Plant Scientists, 2010. Web. 03 May 2016. <http://plantsinaction.science.uq.edu.au/content/314-turgor-loss-cytorrhysis-and-plasmolysis>}}
2. Jones, Hamlyn. Plants and Microclimate: A Quantitative Approach to Environmental Plant Physiology (Third Edition ed.). Cambridge University Press. pp. 73–76. ISBN 9780521279598.
3. Buchner, Othmar, and Gilbert Neuner. "Freezing Cytorrhysis and Critical Temperature Thresholds for Photosystem II in the Peat Moss Sphagnum Capillifolium." Protoplasma 243.1 (2010): 63-71. Web.