| Programmed cell death (PCD) is the genetically regulated disassembly of cells, and it is crucial for a correct development of the body plan. Research indicates that PCD is a key event in the germination of cereal crops, and it determines whether or not the normal process of seeds germination can be executed. The large central vacuole is unique organelles for plant cells, and vacuolar morphology changed significantly during the process of PCD of aleurone layers in germinating cereal seeds. In this study, we explored the vacuolar morphological variation characteristics of aleurone cells in germinating rice (Oryza sativa L.) varieties'?128'seeds during the process of PCD, and revealed the regulation of vacuole on the progress of PCD. All this is by using a variety of microscopy and fluorescent labeling, combined with cell morphology, anatomy and plant developmental biology. The results showed that:(1) the degradation of endosperm starch started from near the embryo in the germination of rice seeds, and then gradually moved to the far end of the embryo, and the activity of ?-amylase showed a trend of rising at the early germinating stage of rice seeds.(2) The programmed cell death of aleurone layers in rice seed originated from the inner layer (near the starch endosperm) to the outer layer (close to the coat), and from near the embryo to the far embryo also.(3) Protein storage vacuoles (PSV) transformed into lytic vacuoles (LV), and the large central vacuole of cells was a remarkable feature in the PCD of aleurone layers of germinating rice seeds.(4) The rupture and disappear of the large central vacuole caused the degradation and disappear of nucleus and cytoplasm, and then cells died.(5) The inhibited vacuoles fusion delayed the course of aleurone layers PCD, thus affecting the germination of rice seeds.(6) Vacuolar processing enzymes mediated by microfilaments might influence the process of aleureone PCD in germinating rice seeds. |
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