Ice management and freeze dehydration of plant cells

Ice management and freeze dehydration of plant cells

Introduction
One of the apparent changes during freezing is the transformation of liquid water to ice. While ice susceptible plant cells get immediately killed upon ice formation, ice tolerant plant cells readily survive exposure to extracellular ice masses in their tissue. Extracellular ice withdraws cellular water which is a temperature dependent process. Freeze dehydration is, additionally, influenced by cell wall rigidity, a factor which is less well understood. Upon extracellular ice formation ice tolerant plant cells either tolerate freeze dehydration that in extreme causes non-lethal freezing cythorrhysis (cells collapse and loose reversibly approximately 80% of cellular water) or survive by supercooling. In supercooled cells water remains liquid inside the cells but below a certain temperature threshold cells freeze intracellularly. The necessary subcellular changes allowing a cell to freeze dehydrate or supercool are not known.

Research questions
The effect of extracellular ice on mesophyll cells is studied in 14 plant species possessing diverse cell wall properties – the following topics are addressed:

  • extent, velocity and dynamic of cellular freeze dehydration, freezing cytorrhysis and supercooling
  • chemical components, structural features and elastic properties of cell walls in relation to the peculiar cell-specific cryo-behaviour
  • subcellular changes during freezing as monitored by high-resolution biophysical and cell biological techniques
  • cellular mechanisms of frost damage

Publications
Steiner, P., Luckner ,M., Kerschbaum, H., Wanner, G., Lütz-Meindl, U. 2018 Ionic stress induces fusion of mitochondria to 3-D networks: An electron tomography study. Journal of Structural Biology, 204, 52-63. DOI: doi.org/10.1016/j.jsb.2018.06.010
Stegner, M., Schäfernolte, T., Neuner, G. 2019 New insights in potato leaf freezing by infrared thermography. Appl Sci, 9, 819. DOI:10.3390/app9050819

Funding
2018-2021 FWF-Project P30139-B32 (PI: Gilbert NEUNER)

Personnel involved
Gilbert NEUNER
Othmar Buchner
Matthias Stegner

National cooperation partner:
Ursula Lütz-Meindl
Phillip Steiner

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