Abstract: The two-year old suspensions derived from the calli of japonica rice (CV. 02428) were normal in cell ultrastructures with well developed organs. However, the number of mitochondrion per cell decreased and starch grains in plastids and vacuoles in cytoplasm appeared 3 days after irradiation with 500R γ-rays. Cell structure changed dramatically with all cell organs disintegrated 6 to 12 days after the radiation indicating that the damage of cell ultrastructure caused by the irradiation is irreversible. Treatement with 5000R γ-rays brought about even greater damage to the suspensions, accelerating the disintegration of cell organs. The suspension cells treated with 1 mmol/L and 5 mmol/L of SA caused loss of growth ability. The suspension cells of 02428 showed a higher sensitivity to both physical and chemical mutagens as compared to the young panicle of the rice.

Key words: Invitro mutagenesis, Japonica rice, Suspension cells, Ultrastructure

摘要： 梗稻02428幼穗继代培养两年具有旺盛分裂能力的悬浮细胞系，有正常细胞结构，各种细胞器发育良好。但经500 R r 射线照射后，细胞结构产生较严重的损伤，表现线粒体数量减少，质体内淀粉粒积累，液泡增加；在照射后第6～ 12天，细胞结构逐渐模糊，细胞嚣消解；说明500 R r射线照射对细胞结构产生了不可逆转的损伤。5000 R r射线照射使悬浮细胞系产生致死损伤，更加速了细胞嚣解体和细胞死亡。1 mmol／L和5 mmol／L的叠氯化钠处理也使悬浮细胞系立即死亡。因此，具旺盛分裂能力的水稻悬浮细胞系对理化诱变处理的敏感性很高。

关键词: 水稻, 悬浮细胞系, 超微结构, 诱变