Microscale modeling of water transport in fruit tissue

• We determine effective cortex tissue water conductivity of ‘Conference’ pear from simulation.
• Simulations with different tissue structures has been done.
• The resistance for water transport of the different tissue compartments is investigated.
• The sensitivity with respect to the diffusivity values of the tissue compartments is calculated.

A model was developed to describe water transport in fruit tissue, taking into account the microstructural architecture of the cell assemblies in the tissue, which leads to a better understanding of the underlying phenomena causing water loss. Pear (Pyrus communis L. cv. Conference) was chosen as a model system. The fruit tissue architecture was generated by means of a cell growth model. The transport of water in the intercellular space, the cell wall network and cytoplasm was predicted using transport laws using the chemical potential as the driving force for water exchange between different microstructural compartments. The model equations were solved on the pear cortex tissue geometry (referred here after as geometry) using the finite element method. The different water transport properties of the microstructural components were obtained experimentally or from literature. The effective water conductivity of pear cortex tissue was calculated based on the microscale simulations. The values corresponded well with measured values of tissue water transport parameters. The model helped to explain the relative importance of the different microstructural features (intercellular space, cell wall, membrane and cytoplasm) for water transport. The cell membrane was shown to have the largest effect on the apparent macroscopic water conductivity.