中文摘要：

利用激光扫描共聚焦显微术对11份同源四倍体水稻亚种间杂种的胚囊结构和双受精特点进行研究，结果表明，所有四倍体杂种均存在一定频率的败育胚囊，败育频率因组合而异，最高的败育率为23．8％，最低为5．5％，平均14．3％。败育胚囊主要有胚囊退化、异常小胚囊、无卵器、无雌性生殖单位和极核位置异常等5种类型。杂种在双受精过程中也存在一定频率的异常，包括胚囊结构正常但未能受精和受精停滞等，其中未能受精的频率为3．5％～11．9％。平均7．9％，受精停滞的频率为1．1％～6．2％，平均3．7％。另外，还存在低频率（平均4．7％）的胚乳发育受阻。认为部分胚囊败育和受精异常（包括未能受精和受精停滞）是导致同源四倍体水稻亚种间杂种结实率降低的主要原因。

英文摘要：

Autotetraploid rice is a new germplasm, in which two sets of genome are brought together into the same nucleus by chromosome doubling. It may be a useful material in breeding because of larger seed size and high potentiality in growth. Rice （ Oryza sativa L. ） consists of two subspecies, i.e. indica and japonica. If the two subspecies are respectively developed into autotetraploid by chromosome doubling and crossed with each other to develop autotetraploid hybrid, the hybrid will have higher heterosis in growth compared with the hybrid between indica and japonica, which maybe become a hopeful way in rice breeding. But low seed setting percentage makes this intersubspecific autotetraploid hybrids cannot be used directly in production. Therefore, it is very important to study the mechanism of low seed setting percentage in the autotetraploid hybrids. Seed setting is the product of the process of plant reproduction, which includes the developments of pollen, embryo sac, fertilization, embryo and endosperm. High rate of sterile pollen and embryo sac, and abnormal fertilization were found in few autotetraploid rice and considered as the reasons that caused the seed setting percentage dropped, but little was known about the reproduction of the hybrids between autotetraploid indica and autotetraploid japonica and how it related to the seed setting rate. In an effort to elucidate the reproduction relation to the seed setting percentage in the autotetraploid hybrids, the structure of embryo sac and its fertilization of 11 autotetraploid hybrids, with controls of two diploid hybrids and one variety were studied by using confocal laser scanning microscopy （ CLSM）. The results showed that （1） embryo sac abortion rate ranged from 5.5% to 23.8%, with the average of 14.3% （Table 3） ; （2） in the mature stage of embryo sac, five kinds of sterile embryo sac were found（Table 2）, i.e. embryo sac degeneration（ Plate Ⅱ-7）, abnormal small embryo sac （much smaller than the normal one） （Plate Ⅱ-8）,