A thermodynamically consistent quasi-double-porosity thermo-hydro-mechanical model for cell dehydration of plant tissues at subzero temperatures

Abstract

Many plant tissues exhibit the property of frost resistance. This is mainly due to two factors: one is related to metabolic effects, while the other stems from structural properties of plants leading to dehydration of their cells. The present contribution aims at assessing the impact of ice formation on frost-resistant plant tissues with a focus on structural properties specifically applied to Equisetum hyemale. In this particular case, there is an extracellular ice formation in so-called vallecular canals and the pith cavity, which leads to a dehydration of the tissue cells to avoid intracellular ice formation, what would be fatal for the cells and subsequently for the whole plant. To address the underlying phenomena in the plant, a coupled thermo-hydro-mechanical model based on the Theory of Porous Media is introduced as the modelling framework. The dehydration of the tissue cells is referred to as of quasi-double-porosity nature, since the water is mobile within the intercellular space, but confined to the cells in the intracellular space and consequently kinematically coupled to them. However, the mass exchange of water across the cell wall is considered. The presented numerical example shows the strong coupling of the underlying processes as well as the quasi-double-porosity feature. Finally, it supports the experimental finding of the vallecular canals as the main location of ice formation.