Abstract
Cell death of inviable F1 hybrid between Nicotiana gossei Domin and N.tabacum L. initiated from basal hypocotyl. Epidermal and cortex cells of hypocotyl were crushed, indicating loss of their protoplast. To more closely analyze collapse of cell during cell death, cultured cells (GTH4) from hypocotyl was used for further experiments. Loss of chloroplasts and mitochondria in the cells after transfer to 26C, condition which induce cell death, was observed by fluorescent microscopy, and number of cells showing low pH increased. GTH4 cell at 37C had high viability and complicate inner structure of which vacuole was divided into many vesicles by strands of cytoplasm. This structure was maintained just after transfer to 26C, but it turned into uniform density without any strands of cytoplasm. Finally, protoplasts were shrunk inside the cell. These findings indicated that execution of cell death is caused by quick collapse of vacuole under the lethal condition.
