Preliminary Study Of Programmed Cell Death Process During The Salt-induced In Root Tip Cells Of Vicia Faba

In this study, the root tip of vicia faba（Vicia faba L.）was used as test materials toinvestigate the programmed cell death induced by salt stress in root tip cells, as well asmorphological, molecular biology and signal molecular variations in the programmedcell death process.The test results showed that300mmol/L NaCl treatments for6h could induceprogrammed cell death in root tip of vicia faba. In morphology, cell shrinkage anddeformation, nuclear and cytoplasm were condensed. Stained by AO/EB, the cytoplasmgreen fluorescent of programmed death cell were reduced, nuclear cells were stainedwith EB deepen to orange.In biochemistry and molecular biology, nucleic acid enzymes were activated;progressive degraded the cell nucleus DNA in180bp as unit, stressed for6h shownDNA ladder by DNA agarose gel electrophoresis. Detected by TUNEL in situ end,programmed cell death cells were situ end labeled and presented positive reaction. Therelease of cytochrome C is the pre-reaction of programmed cell death,300mmol/L NaCltreated for1h could induce the release of cytochrome C from the mitochondria to thecytoplasm.The content of calcium ions in the cytoplasm rising rapidly when300mmol/LNaCl stress Vicia faba root tip from begin to30min; The active oxygen contentincreased slightly but changed little in300mmol/L NaCl stress from early to6h, thecontent rapidly rising after6h treatment. Antioxidant enzymes (SOD, POD, CAT)activity increased rapidly in the early stage of salt stress to3h, and activitydecreased.after4h.In summary, calcium and reactive oxygen species are important signalingmolecules that induce programmed cell death. Antioxidant enzyme system first removeexcess reactive oxygen species in300mmol/L NaCl stress. The active oxygen contentincreased and cause oxidative damage when scavenging ability reduce. On the otherhand, the mitochondrial permeability transition pore opening impact across themitochondrial membrane Ca2+transport system, the concentration of cytoplasmic Ca2+ increased. Cytochrome C released into the cytoplasm, and activate a range of othersignaling molecules, and induce the apical programmed cell death. Morphology showeda series of characteristics such as cell volume shrinkage, nuclear condensation, nuclearbudding. Nuclease is activated and degrated nuclear DNA as180bp per unit inbiochemistry and molecular biology. DNA ladderc can be shown in agarose gelelectrophoresis and TUNEL detected a positive reaction.