Investigation of the mechanics of single tomato fruit cells

The mechanical behavior of single tomato fruit cells has been characterized using high strain-rate microcompression testing. Single cells isolated by gentle washing from inner pericarp tissue were compressed to a wide range of deformations at a speed of 1500 mu m/s, and then released. The cells were larger than any tested previously by microcompression, and had very low initial turgor. Force-deformation data were modeled to find cell wall material properties, assuming water loss during compression could be neglected because of fast compression. Repeat compression-release experiments were conducted to discover when cell deformation was no longer recoverable upon release. Cells from three commercially grown tomatoes were elastic to deformations of just over 11%. The elastic moduli of the cell walls were found by modeling to be 30 to 80 MPa, significantly lower than suspension-cultured cell walls. The cell walls yielded at about 2% wall strain. High-speed compression testing is a powerful tool for studying low turgor cells, such as those found during ripening.