Programmed Cell Death Induced By Ce～(4+) In Suspension Culture Of Arachis Hypogaea And Porphyridium Cruentum

Programmed Cell death (PCD) induced by Ce4+ in suspension culture of Arachis hypogaea and Porphyridium cruentum cells were examined respectively, using DNA Laddering, Hoechst-PI-SDH triple-staining and transmission electron microscopy. The results indicated that: l.Ce4+ stress could induce PCD in suspension culture of A. hypogaea and P. cruentum cells. And there was a stress threshold in stress on cells. 2. The live cells, cells undergoing apoptosis and those undergoing necrosis could be distinguished under fluorescence microscopy, using Trypan blue-SDH double-staining or Hoechst-PI-SDH triple-stain. 3. PCD in suspension culture of A. hypogaea cells was observed at 7d after 1.0 mmol/L Ce4+ treatment with transmission electron microscopy. The ultrastructural changes in the cells as following: The nucleolus disintegrated, chromatin condensed and margined. The mitochondrion membrane constricted and ruptured, and deteriorated. The vacuoles fused and disrupted. The endoplasmic reticulum cisterna dilated, and then formed phagocytic vacuole. 4. The content of chlorophyll in leaves of A. hypogaea declined after 1.0 mmol/L Ce + treatment. And the activity of superoxide dismutase (SOD) increased first and then decreased with prolonged treatment time. But the content of chlorophyll and SOD activity in control were stable. 5.250 mmol/L Ca2+ and Mg2+ could induce PCD in suspension culture of A. hypogaea cells after stress on cells for 4h, but 250 mmol/L Zn2+ couldn't. 6.The content of polysaccharide of cells in suspension culture of P. cruentum cells induced by 1.0 mmol/L Ce4+ at 7d was one point six times that of control, but its biomass was clearly reduced.