【作者】 刘红艳；

【导师】 徐才国；

【作者基本信息】 华中农业大学 ， 作物栽培与耕作， 2003， 硕士

【摘要】 水稻是世界上最重要的粮食作物之一，在我国粮食生产中占有举足轻重的地位。通过长期育种，水稻单产已经达到相当高的水平，继续运用常规育种法来提高水稻单产已经难有大的突破，需要另僻溪径。大量研究发现：籼粳亚种间杂种的营养器官和产量性状表现出强大的杂种优势，如能有效加以利用，将有可能使水稻产量取得新的突破。但由于籼粳亚种间杂交存在F₁代结实率偏低的问题，使得目前难以直接利用其杂种优势。因此探讨籼粳亚种间杂种不育机理，对于克服亚种间杂种不育，有效利用其杂种优势具有重要的理论价值和实践意义。 本研究主要以2个籼稻品种南京11和IR36、1个粳稻品种秋光为基本材料，配制籼粳亚种间组合南京11／秋光、亚种内品种间组合南京11／IR36，其中南京11／IR36为对照，着重从以下4方面来探讨籼粳亚种间杂种F₁代不育的原因：1)雌雄配子形成过程；2)花粉在柱头上的附着、萌发以及花粉管伸长情况；3)花粉育性；4)胚囊受精情况。 主要实验结果如下： 1．运用石蜡切片法对南京11／秋光和南京11／IR36的F₁代雌雄配子发育过程进行了详细的细胞学观察，结果发现：二供试组合的小孢子母细胞在四分体时期之前发育正常，单核期后亚种间组合（南京11／秋光）F₁出现部分花粉败育（败育率为20.27％），而品种间组合（南京11／IR36）F₁则表现正常（败育率为2.25％）；大孢子母细胞在发育为胚囊过程中，亚种间组合（南京11／秋光）F₁除少数无胚囊分化外，绝大多数都有胚囊分化，并且前期发育比较正常。这些分化出的胚囊一般能进行第一次有丝分裂形成2核胚囊，但大多数不能继续进行第二次、第三次有丝分裂从而不能形成正常的8核胚囊，而对照组合（南京11／IR36）F₁则表现正常。 2．利用扫描电镜观察亚种间组合南京11／秋光和对照品种间组合南京11／IR36的F₀代、F₁代的花粉在柱头上附着、萌发以及花粉管伸长情况，结果发现：在F₀代和F₁代，亚种间组合南京11／秋光的花粉附着量分别为0.48个／cm²和0.2个／cm²，均少于品种间组合南京11／IR36的花粉附着量3.5个／cm²和3.62个／cm²；这些附着在柱头上的花粉粒大多能萌发，但亚种间组合（南京11／秋光）F₁的花粉粒萌发后，花粉管在柱头表面出现扁平、弯曲、盘绕等异常现象，而品种间组合（南京11／IR36）F₁的花粉管却能正常伸长。这表明籼粳亚种间组合的花粉与柱头存在严重不亲和性。 3．对成熟花粉粒进行碘-碘化钾染色和荧光染色观察，结果表明：碘-碘化钾染色反应中，可育花粉（即深染花粉粒）所占比例在亚种间组合（南京11／秋光）F₁中约为25％，而在对照品种间组合（南京11／IR36）F₁中约为80％；荧光染色中，有 水稻釉粳亚种间杂交子一代不育机理的探讨活性的花粉（即口+II）类花粉粒)所占比例在亚种间组合南京11/秋光中约为40%，而品种间组合南京11八R36中约为80%。从这两种方法所得花粉育性的结果来看，皆是亚种间组合低于品种间组合，这说明花粉育性主要通过淀粉积累的多少和花粉活性的强弱间接影响粕粳杂种F，代的结实性。 4.通过盐酸浸泡结合碘一碘化钾染色来观察胚囊受精情况，结果发现:亚种间组合（南京11/秋光）F:的胚囊受精率一般在25%-30%之间，而对照品种间组合（南京江R36）F，在6俄⁹湍之间，这说明结实率低可能主要是由于受精率低造成的。 5.通过雌雄配子败育相对重要性比较，结果表明:两供试组合皆是雌配子败育比例大于雄配子败育比例，其中亚种间组合（南京11/秋光）F，中雌配子败育重要性占58.20%，雄配子占41.80%，而对照品种间组合（南京八R36）F:中雌配子占53.47%，雄配子占46.53%，这说明亚种间杂种F:中雌雄配子败育是导致其败育的主要原因，其中雌配子败育占主导地位，雄配子败育占次要地位。更多还原

【Abstract】 Rice is one of the most important crops in the world. It plays an important role in our country. But its yield per acre has pacing up and down for more than ten years. If we can’t improve the yield drastically, we will face the danger of rice food in the 21 century. The FI hybrid between indica and japonica has great hybrid vigor in vegetative organ and yield trait. If we can use it directly, we may make a breakthrough in yield But we can’t utilize it directly at present because of the low seed set that exists in them. So studing on the sterile mechanism of FI hybrid has an important sense of theory and practice.In order to analyze the cause of the highly spikelet sterility observed in the FI hybrid between Indica and Japonica, stamen and pistil were paraffin-sectioned at 8μm thickness and stained with Ehrlich’s hematoxylin to observe the male and female development of F] hybrid. The adsorption and germination of pollens in the hybrids within and between Indica and Japonica F1 hybrids also be observed by scanning electron microscope. Meanwhile, pollen viability were observed with potassium iodide solution(l2-KI) and fluorescent diacetate acetone(FDA); the embryosac’s fertility were examined by immersed with hydrochloric acid and stained with I2-KI. Results of the cytological studies of partial male and female sterility’ in FI hybrids between subspecies crosses Nanjing11/Qiuguang, varietal crosses Nanjing11/IR36 were described as follows:1. Anther development was usually normal before tetrad stage. The partial pollen abortion in F1 hybrid of Nanjing 11/Qiuguang occurred after uni-nucleate stage(the microspore sterility was 20.27%). By contrast, Nanjing11/IR36 were normal from the beginning to the end(the microspore sterility only was 2.25%). In the development of macrospores in the subspecies hybrid, there were some embryosacs that there was no differentiation. Those embryosacs that could differentiate were normal in early stage, and could be divided into two nucleate stages in the first mitotic division, but many of them couldn’t be divided in the second and the third mitotic division in the follow time. So itcan’t format the normal embryosac-eight nucleate stage. The hybridization betweenvarieties was normal.2. The recognition between pollen grains and stigma in Nanjing 11/Qiuguang and Nanjing11/IR36’s FO and FI were observed under scanning electron microscope. The results as follows: in F0 and F1. the adhension number between stigma and pollen insubspecies crosses were little than that in varieties crosses. It was 0.48 Entris/cm2 and 0.2 Entris/cm2 in Nanjing11/Qiuguang’s FO and FI respectively, 3.5 Entris/cm2 and 3.62 Entris/cm2 in Nanjing11/IR36’s F0 and F1 respectively Many of the pollen grains that attached to the stigma can sprout in general. But some of the spermary presented variant morpha in their elongation stage. Such as enlargement, curvifoum, twist and so much in the stigma’s surface in the subspecies crosses. While the spermary of the varietal crosses was normal in their enlonged. This suggested that: the pollen and stigma in the subspecies hybrid has bad compatibility.3. The mature pollen fertility was observed by I2-KI stainability and FDA stainability. In Nanjing11/Qiuguang. the I2-KI stainability was 25%, the FDA stainability was 40%(I+II). While in Nanjing11/IR36. the I2-KI stainability was 80%, the FDA stainability was 80%(I+II). These indicates that both starch accumulation and dehydrogenase’s force influencecd the setting percentage of F] hybrid indirectly.4. The embryosac’s fertility was observed by immersed with hydrochloric acid and stained with I2-KI. In Nanjing 11/Qiuguang, the fertility of embryosac was 25%-30%, but it was 60%-90% in Nanjing 11/IR36. This indicates the low fertilized rate was the cause of the low seed set in the subspecies crosses.5. Comparison the pollen and embryosac’s relative importance showed: the proportion of subspecies crosses’ embryosac was 58.20%, pollen’s was 41.80%; whereas varietal cross’ embryosac was 53.47%, pollen’s was更多还原