Salt Stress-Induced Apoptosis in Plants——a Possible Resistance Mechanism to Salt Stress

Previous study has showed that apoptosis-like cell death can be induced under moderate salt stress in plants. In this paper, we studied the cell death induced by salt stress in maize, rice and tobacco roots utilizing DNA Laddering, paraffin sectioning-based TUNEL and chromosome spreading-based TUNEL simultaneously. The characteristic morphological and biochemical features showed apoptosis induced by salt stress may be a universal phenomenon in plants, but some differences may lie in various species. These results provided a valuable insight into studying the physiological mechanism of stress resistance in plants. In addition, we compared the in situ labelling technique based on chromosome spreading with that based on paraffin sectioning. We proposed according to the results that chromosome spreading-based in situ labeling technique should be suitable to detect individual cell death qualitatively and quantitatively with high efficiency, low background and detailed description of apoptotic changes at chromosome, nuclear and DNA levels.