The soft plant tissues as fruits and vegetables are highly susceptible to mechanical damage. This damage causes irreversible changes in structure, color and taste of the tissue. Having analysed results published by many researchers, the author of this work have concluded that present methods of damage investigation in plant tissues do not allow investigation in real-time cracking of the plant tissue subjected to external loading. In order to observing cracking processes from their beginning to the strength of compressed sample of the tissue author of this work applies acoustic emission method (AE method). Simultaneously measurement AE signal and stress-strain curve allows obtaining critical stress and critical strain at the beginning of the tissue cracking, whereas failure stress and failure strain accompanied by total count sum of AE describe strength of the compressed sample. Experiment was done for samples of two varieties of potato tuber: Danusia and Kuba parenchyma tissue, both outer core and inner core. Tissue structure as a distribution of cell size (area and perimeter) and cell elongation was quantitatively described. Compression tests with different quasi-static crosshead speed were carried out to the strength of the cylindrical samples. The samples had different turgor level. Comparison of experimental results with theoretical model of single plant cell shows that the source of the AE signal in compressed plant tissue can be cell wall cracking. The experiment showed that increase in both the crosshead speed and the turgor causes decrease in the critical stress and the critical strain. The failure stress of potato tuber tissue does not depend on the crosshead speed but it linearly decreases when the turgor increases. Total count sum of acoustic emission signal logarithmically increases with the crosshead speed and linearly increases with the turgor. Cell size of potato tuber tissue does not influence on the critical state but the failure stress and the failure strain are lower for tissue with bigger cells.