Abstract: TUNEL(TdT_mediated dUTP_biotin nick end labeling), a new method for DNA cleavage detection in apoptotic cells, enables in situ detection of fragmented DNA based on visualizing DNA 3'_OH nicks in nuclei. Here we report the application of TUNEL in detection of apoptosis of carrot protoplasts. Results obtained using DNA electrophoresis, comet assay and TUNEL are compared, which confirm the reliability of TUNEL in detection of apoptosis of plant protoplasts.