中文摘要：

该研究以文冠果花发育不同时期采集的花药和胚珠为材料，采用光学及电子显微技术对花的性系统特征、胚珠发育及自交败育等有性生殖特征进行观察分析，以揭示文冠果开花多、结果少的内在机理。结果显示：（1）文冠果植物产生大量雄花和很少的两性花，表现隐形雌雄同株的性系统类型。（2）文冠果花拥有5个独特的金黄色角状附属物；成熟花粉粒球形，3孔沟，沟在花粉极面不相连，花粉表面有疣状纹饰；花主要以风媒传粉。（3）柱头3裂，开花时柱头表面布满丝状乳突细胞，属于干燥型。（4）卵球形弯生胚珠内有一弯曲的长胚囊，胚囊被厚珠心包围。胚珠受精后，珠孔与合点之间的珠柄侧外珠被的局部细胞平周和垂周分裂产生一个径向突起，伸向胚囊，与胚囊纵轴略成直角；受精后水和可溶性物质不断进入膨大的胚囊；幼胚的两子叶从胚囊珠孔端的管状部位进入合点端大的腔室中。（5）在胚发育早期，两片子叶是对称的，但在授粉35 d后，具有较大半径的一子叶比另一子叶的体积大；授粉后23 d以前，胚囊内的液态内容物含有游离核胚乳和少量细胞化胚乳，这个时期的胚珠可以鲜食。（6）自交传粉后，胚珠与幼果在合子形成后的不同时期败育。研究表明，文冠果与无患子科的其它植物有很多相似的有性生殖特征，但文冠果也具有一些异常特征，如花存在附属物及每子房室中有较多的胚珠等。

英文摘要：

Sexual system, ovule development and abortion of self pollinated fruits in Xanthoceras sorbifolium were investigated through direct observations, light and scanning electron microscopy to understand why a very small proportion of flowers give rise to mature fruits, based on the samples of male and bisexual flowers in different developmental stages. The results indicated that： （1） the plant bears a large proportion of male and a limited number of bisexual flowers and exhibits cryptic monoecy. （2） There are five unique golden horn like appendages in a flower. Mature pollen grain is spheroidal, tricolporate and parasyncolporate, with verrucate ornamentation. The flowers are mainly wind pollinated. （3） The dry stigma is trilobed and the surface is densely covered with filiform papillae at anthesis. （4） The ovoid and amphitropous ovule contains a long curved embryo sac that is embedded within the massive nucellar tissue. After fertilization, a radially stretched bulge is produced by local periclinal and anticlinal divisions of the outer integument between the micropyle and the chalaza at the raphal side, which extends into the embryo sac perpendicular to its longitudinal axis. The fertilized embryo sac forms a sink into which water and soluble materials are draw. Two cotyledons of the young embryo reach the vesicle of the chalazal end of the embryo sac by growing along the neck of the micropylar end of the embryo sac. （5） In the early development of the embryo, the twin cotyledons are symmetrical. The cotyledon having the longer radium of curvature becomes much larger than the other cotyledon after 35 days after pollination （DAP）. The liquid content of the vesicular embryo sac contains free nuclear endosperm and a slight amount of cellular endosperm before 23 DAP, during which the fresh ovules are edible. （6） Post zygotic abortion of self pollinated ovules and young fruits occurs at various stages of development. The studies indicated that many sexual reproductive features of X. sorbifoli