In situ mechanical testing of fully hydrated carrots (Daucus carota) in the environmental SEM

We demonstrate the use of the Environmental Scanning Electron Microscope (ESEM) for in situ observation of mechanical tests on carrot (Daucus carota) parenchymal tissue. The ESEM tolerates several Torr of water vapour in the specimen chamber, thus allowing fully hydrated specimens to be examined at high resolution, but without preparation. Three tests were performed, involving slicing, tension and compression The manner in which stress was distributed in the tissue, crack propagation and cell wall distortion were all observed in real time. (C) 1998 Annals of Botany Company.