Understanding microstructural deformation of apple tissue from 4D micro-CT imaging

Z. Wang, S. Rogge, M. Abera, M. van Dael, V. Van Nieuwenhove, P. Verboven, J. Sijbers, B. Nicolaï
Water transport in plant tissues is often associated with deformation of the tissues. The ability to visualize and model this deformation is an integral part of better understanding of the relevant parameters involved. Traditional imaging techniques are both time-consuming and destructive, this makes them unsuitable for visualizing the tissue deformation process, as both time and environmental conditions are critical parameters. However, even with the use of non-destructive imaging techniques such as X-ray micro-computed tomography (micro-CT), visualizing the dehydration process is difficult due to the unstable nature of the samples as well as limitations imposed by the accuracy of conventional imaging of deforming objects. As a result, micro-CT data of deforming tissues can often not be processed easily. Here, we utilized micro-CT with a modified fast scan protocol to obtain high-resolution 4D data to more accurately visualize the deformation of apple cortex samples during dehydration such that the deformation process can be quantified. A cortex sample of approximately 4×3.2×4.5 mm (L×W×H) from a 'Kanzi®' apple was excised and dehydrated in a controlled environment of 25°C and 50% RH, which was subjected to modified fast scanning every 10 min for 4 h with a voxel resolution of 3 µm. The reconstructed images yielded a time series of high resolution 3D data showing cellular structure of the apple cortex sample through the first 4 h of the dehydration process. The differential shrinkage rates of the outer, middle and inner cell layers of the samples were analysed, along with the size and positional changes of cells within the dehydrating samples in reference to the defined layers. We expect such quantitative description of cell and cell layer deformation to be useful in enhancing the accuracy of hydro-mechanical models of plant tissues.
Wang, Z., Rogge, S., Abera, M., van Dael, M., Van Nieuwenhove, V., Verboven, P., Sijbers, J. and Nicolaï, B. (2018). Understanding microstructural deformation of apple tissue from 4D micro-CT imaging. Acta Hortic. 1197, 7-14
DOI: 10.17660/ActaHortic.2018.1197.2
apples, micro-CT, dehydration, deformation, microstructure, 4D

Acta Horticulturae