萝卜CMS不育系与保持系小孢子发生的细胞学研究

Cytological investigation on microsporogenesis of cytoplasmic male sterility in radish (Raphanus sativus L.)

研究了萝卜胞质雄性不育系A2 、A4及其相应保持系B2 、B4的小孢子发生与花药壁发育的细胞学特征。结果表明 ,不育系A2 的绒毡层细胞在四分体时期出现异常 ,小液泡增多 ,至单核期汇合形成大液泡 ,绒毡层细胞异常膨大 ;小孢子外壁染色浅 ,细胞壁受到破坏 ,最后与绒毡层一同降解。不育系A4在减数分裂期即表现出异常 ,绒毡层异常肥大 ;花药发育后期 ,小孢子外壁亦染色较浅 ;绒毡层细胞融合形成细胞团块侵入药室挤压小孢子 。

The cytology of the microsporogenesis and development of anther wall of cytoplasmic male sterile (CMS) lines A 2, A 4 and its maintainer lines B 2, B 4 was studied. The results revealed that the tapetal cells of the male sterile line A 2 developed abnormally at tetrad stage, and they became vacuolated and numerous small vacuoles are present; furthermore, the small vacuoles fused into large ones. Exine of microspore was light stained, and cell wall was destructed. Finally with degeneration of the tapetal cells, the pollen aborted. The tapetal cells of CMS line A 4 enlarged abnormally at meiotic phase, pressing microsporocyte seriously. Lately, light-staining exine of microspore could not be observed, and tapetal cells fused to form big lump invading the loculi, and finally leading to pollen grain abortion.