烤烟‘南江3号’大小孢子的发育及雌雄配子体的形成

Megasporogenesis,Microsporogenesis and Development of Female and Male Gametophytes of Flue-cured Tobacco‘Nanjiang 3'

以贵州烤烟主栽品种‘南江3号’为试验材料,采用石蜡切片法对其大小孢子发生及雌雄配子体发育进行观察研究,探讨烤烟生殖过程与花蕾形态变化的关系,为田间栽培控制花期以及实现烟草的遗传调控提供理论依据。结果表明：‘南江3号’雄蕊的花药壁发育为基本型,绒毡层为腺质异型;小孢子母细胞减数分裂为同时型,四分体排列方式有四面体型和十字交叉型2种;成熟花粉为二细胞型,花粉具3或4个萌发孔。胚珠倒生,薄珠心;孢原细胞体积较大,直接发育为大孢子母细胞,4个大孢子呈线性排列;胚囊发育为蓼型,成熟胚囊为7细胞8核。烤烟‘南江3号’的雌蕊发育晚于雄蕊,当雄蕊发育为四分体时期时雌蕊才开始发育,且花蕾发育到5.0～6.8cm时胚囊才逐渐成熟。研究认为,烤烟‘南江3号’的大小孢子及雌雄配子体发育各阶段与花蕾形态有关,通过花蕾的形态可初步判断各个发育阶段。

Flue-cured tobacco‘Nanjiang 3’was a kind of main cultivated varieties in Guizhou Province.Paraffin section method was employed to observe its anatomical structure of microsporogenesis,megasporogenesis and development of female and male gametophytes.The results showed that,the anther wall is defined as basic development type with glandular veriform tapetum.The cytoplasm of microspore mother cell undergoes simultaneous division and produces tetrahedral or decussate tetrad.The mature pollen belongs to 2cell type and has three or four apertures.The ovary of flue-cured tobacco‘Nanjiang 3’is anatropous with thin nucellus.The archesporial cell develops to megaspore mother cell directly and has larger volume.Four megaspore cells form a linear tetrad.The development pattern of embryo sac is polygonum type,finally forms 7-cell or 8-cell nucleate mature embryo sac.Stamen develops earlier than gynoecium and the period of microsporogenesis,megasporogenesis and development of female and male gametophytes can be judged by appearance from the flower bud.