通过百合远缘杂交和倍性间杂交观察到，当杂交组合的胚乳中含有5个或5个以上相同的基因组时，胚乳发育较好，杂交容易成功；否则胚乳不发育或很难发育，杂交也难以成功。分析表明这与百合产生四孢八核胚囊有关，因为根据其大孢子形成过程得到推论“三倍体的百合因减数分裂异常产生的卵细胞为非整倍体，但极核永远为六倍体”。为了从细胞水平和分子水平上揭示这种现象的机制，本项目拟根据胚乳发育的差异首先人工授粉进行不同类型组合的杂交，利用组织切片确定胚乳发育程度，用GISH和FISH技术分析胚乳的基因组构成，根据胚乳发育的程度对不同发育时期的胚珠和叶片取样，分析激素和 淀粉合成酶水平，提出mRNA后，制备cDNA，并对不同组合的cDNA测序，通过分析，发现与百合胚乳发育相关的特异基因，从而为揭示三倍体百合胚乳高度发育机制提供细胞和分子方面的证据。

It was observed that the endosperm of lily distant or interploid crosses (3x x 2x/4x) developed well and the crosses were usually successful when it contained ≥ 5 same genomes; otherwise, it hardly developed or aborted and the crosses were usually unsuccessful. Theoretic analysis indicates that this phenomenon related with lily tetra-sporic embryo sac, because it is deduced that “each embryo sac of triploid lilies usually contains an aueuploid egg cell and a hexaploid secondary nucleus regardless of abnormal meiosis”, based on normal megasprogenesis. In order to unveil its mechanism at cellular and molecular level, different interploid crosses will be selected and fertilized with artificial method based on the difference of their endosperm development. After fertilization, the ovules will be analyzed with anatomic method to check the extent of endosperm development. Based on the extent of endosperm development, the ovules and leaves at different stages after fertilization will be sampled. The samples will be tested for their phytohormone and starch synthase RNA will be isolated from ovules and leaf respectively, then cDNA will be prepared. The cDNA of different crosses will be sequenced. By analysis of the above data, it would be possible to find some specific genes related with endosperm development in Lilium. By comparing the genes with the identified genes expressed in endosperm of Arabidopsis, it will provide some cytological and molecular evidences to unveil the mechanism of highly developed endosperm of triploid Lilium.