Studies On Signal Regulation Of Programmed Cell Death Induced By NaCl In Vicia Faba L. Guard Cells And Epidermal Cells

The peels from pea (Vicia faba L.) represent a monolayer consisting of two type cells: Phototrophic (guard cells) and chemotrophic (epidermal cells).GC and EC usually encounter the same extent of environmental stimulation.. While they have different cellularity and physiological functions, and have quite different response to the same stimulation, as a result,they are different in signal transmission, oxidation stimulation, response extension and the apparent phenomenon. In this research NaCl was used to induce PCD of GC and EC, our purpose is to investigate the difference between GC and EC that intimidated by NaCl . We also investigated the difference response between EC and GC to external ROS and Ca²⁺.The result showed,NaCl can induce PCD both in the GC and in the EC effectively. Along with the extend of the time, the percentage of PCD dead cells of GC and EC increased, PCD was induced earlier and the percentage of PCD cells was significantly higher in EC than in GC, pre-treated with external anti-oxidation ASA effetely retarded the initial of PCD both in EC and in GC. The effect of ASA was more obvious in GC than that in EC. And the addition of external oxidation H₂O₂ had the opposite effect, while the effect was also more obvious in GC than that in EC. These results indicated the redox status participate the pathway regulation for salt stress-induced PCD both in GC and in EC.The difference between GC and EC in responding to NaCl, ASA and H₂O₂ might because that GC contains more organelles, such as mitochondria and chloroplasts, which are important organelles to participate ROS metabolism than EC.Ca²⁺ played a key row in mediating the process of PCD. In our experiment, external Ca²⁺ (6mmol/L, 20mmol/) could induce PCD, pre-treatment with EGTA and CoCl₂ could reduce the percentage of cell death induce by NaCl. While EGTA or CoCl₂ was also could induce PCD both in EC and in GC. These indicated that thebroken of relatively stable status can induce PCD. There were still significant difference in the percentage of cell death during Ca induced PCD between GC and EC. All the results indicated that the organelles difference between GC and EC contribute a lot in the PCD signal pathways. More work need to be done to investigate the details.