Ice mass accumulation in plant tissues

At sub-zero temperatures, there is the risk of ice formation in plant tissues. While ice susceptible plant organs are damaged immediately after the formation of ice, ice tolerant organs can withstand ice formation in their tissue. As plants consist in a large part of water, the amount of ice formed must be considerable. There is increasing evidence that ice growth is a highly controlled process. But it is not understood, how ice growth is controlled and how cellular water is segregated to the ice. We want to shed light on the importance of predetermined spaces for ice mass accumulation and the survival of freezing conditions in plants.

By comparing functionally divers species, we want to assess the spatial confinement of ice masses in leaves and buds and how this is managed by targeted ice segregation at specific loci. Due to cellular dehydration the amount of ice increases continuously with decreasing temperature. What happens when the extent of ice exceeds the available intercellular space volume – do plants suffer from tissue rupture?

With an innovative pool of methods, we intend to analyze the ice crystal shape and their attachment to cell walls. We plan to study the overall freezing behavior but also to quantify the amount of ice formed during freezing at certain temperatures. The molecular components of ice crystals will be analyzed. The combination of novel methods will enable to better understand biophysical and -chemical aspects of ice growth in plant tissues and mechanisms of ice segregation to predetermined spaces.

The project is based on a cooperation of the University of Natural Resources and Life Sciences (Institute of Biophysics; Notburga Gierlinger) and the University of Innsbruck (Department of Botany; Ilse Kranner and PI Gilbert Neuner).