摘要
本文对普通栽培稻不同品种类型间杂种小穗败育的细胞学基础及雌性败育的过程进行了研究,结果表明:(1)引起杂种小穗败育的原因有胚囊败育、花粉败育、开花时花药不开裂和雌雄异熟。其中胚囊败育而丧失受精能力是引起低结实率的最重要的因素,开花时花药不开裂和雌雄异熟在一定程度上形成了雌雄性细胞时间和空间的隔离屏障。(2)杂种植株的所有大孢子母细胞都能进行正常的减数分裂,形成四个大孢子,败育主要发生在靠近合点端的功能大孢子分化形成胚囊的早期,有的功能大孢子在进行第一次有丝分裂前便萎缩解体,多数走向败育的功能大孢子能完成一次或二次有丝分裂,形成二核或四核败育胚囊。败育的共同特征是无液泡的分化,细胞质少或退化,在败育胚囊残迹部位,解体的珠心细胞和萎缩的胚囊残渍混杂垛叠。已受精的杂种子房没有观察到胚及胚乳发育的异常。籼粳杂种胚囊败育频率较高。
15 intersubspecific hybrids from Ory-za sativa were employed to investigate the cytological factors causing poor spikelet fertility and the characterization of female abortion. The results present as following: (1) The factors affecting the seed-set rate of intersubspecific hybrids included embryo sac sterility, pollen sterility, anther indehiscence and non-synchronization of male and female sexual organ development in the same spikelet. Embryo sac sterility is the most important factor causing the low seedset rate, and for certain hybrids the non-synchronization of sexual organ development is the main reproductive barrier hampering the fertilization of hybrids. (2) All the
megaspore mother cells underwent a normal meiotic division which gave rise to tetrad of megaspore. Most of sterilization were initiated at early stage when the functional megaspore closest to the chala-zal pole developed into embryo sac, e, i. some of the functional megaspore withered before first mitotic devision and the others degenerated after one or two successive divisions, which results in abortion of embryo sacs with two or four nuclei. The degenerated embryo sacs are characterized with no vacuole differentiation, less or withered cytoplasm and nuclei towards collapse. The stages of degeneration and freqencies of degenerated embryo sacs in different combinations were diversified.
出处
《实验生物学报》
CSCD
1997年第3期335-341,共7页
Acta Biologiae Experimentalis Sinica
关键词
水稻
亚种间杂种
雌性不育
杂种不育
细胞学
Rice (Oryza sativa). Intersubspecific hybrid. Female sterility. Hybrid sterility.
