钙在高等植物中被称为第二信使,与植物的有性生殖有关.为了研究水稻(Oryza sativa L.)花药中钙的定位与花粉败育的关系,利用焦锑酸钾沉淀法研究了非花粉型细胞质雄性不育系G37A及其保持系G37B花药的发育过程及其细胞中Ca2+的分布变化.研究发现,在2个材料间花药中钙的分布存在大量差异.G37B的可育花药在花粉母细胞时期及二分体时期,很少看到有Ca2+的沉积;而在单核花粉时期,Ca2+沉积急速地增加,主要定位在绒毡层细胞、花粉外壁外层及乌氏体的表面;随后花药壁上沉积的Ca2+减少而花粉的外壁外层仍然有很多Ca2+沉积物.相反,G37A的不育花药在花粉母细胞时期和二分体时期有大量的Ca2+沉积在小孢子母细胞和花药壁,中间层和绒毡层特别多.在二分体时期之后,不育花药的Ca2+沉积减少,特别是绒毡层内切向质膜附近的Ca2+几乎消失.但是同时期的可育花药中,有大量的Ca2+沉积在绒毡层.不育花药的Ca2+沉积在开花几天后消失.根据研究结果推测在不育花药发育早期中更多的钙离子与花粉败育有一定的关系.%Ca2+ is a well-known "second messenger" in higher plants and is related to their sexual reproduction. To test the effects of calcium localization on pollen abortion in developing rice anthers, calcium distribution during anther development in no-pollen type cytoplasmic male sterile (CMS) rice G37A and its maintainer line G37B at different stages was examined by potassium antimonate precipitation method. Our study showed that many differences existed in Ca2+ distribution in developing anthers between the two studied rice lines. In the fertile anthers of G37B,few Ca2+ precipitates were detected at the pollen mother cell stage and the dyad stage. However, Ca2+ precipitates dramatically increased in the tapetal cells, on the exine of pollen grains and the surface of Ubisch Bodies at the uninucleate pollen stage. After this,Ca2+ precipitates decreased on the anther wall,although many Ca2+ precipitates still existed on the exine of pollen grains. In the sterile anthers of G37A,abundant Ca2+ precipitates accumulated in the microsporocyte,on the anther wall and especially in the middle layer,the tapetum and the ubisch bodies located at the pollen mother cell stage and the dyad stage. After the tetrad stage,Ca2+ precipitates in sterile anthers of G37A decreased generally, and could not be detected at the inner longitudinal plasma membrane of the tapetum. The results proposed that redundant calcium precipitates in sterile anthers may be related with pollen abortion.Kev words: Rice;CMS;Pollen;Potassium antimonite;Ca2+
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