A meshfree model for plant tissue deformations during drying

Plant tissue has a complex cellular structure which is an aggregate of individual cells bonded by middle lamella. During drying processes, plant tissue undergoes extreme deformations which are mainly driven by moisture removal and turgor loss. Numerical modelling of this problem becomes challenging when conventional grid-based modelling techniques such as finite element and finite difference methods are considered, which have grid-based limitations. This work presents a meshfree approach to model and simulate the deformations of plant tissue during drying. This method demonstrates the fundamental capabilities of meshfree methods in handling extreme deformations of multiphase systems. A simplified two-dimensional tissue model is developed by aggregating individual cells while accounting for the stiffness of the middle lamella. Each individual cell is simply treated as consisting of two main components: cell fluid and cell wall. The cell fluid is modelled using smoothed particle hydrodynamics and the cell wall is modelled using a discrete element method. Drying is accounted for by the reduction of cell fluid and wall mass, and turgor pressure, which causes local deformations of cells, eventually leading to tissue scale shrinkage. The cellular deformations are quantified using several cellular geometrical parameters and a good agreement is observed when compared to experiments on apple tissue. The model is also capable of visually replicating dried tissue structures. The proposed model can be used as a step in developing complex tissue models to simulate extreme deformations during drying.