Genetic and physiological mechanisms of self-incompatibility deficiency and evolutionary backgrounds in establishment of self-compatible strains in Lilium longiflorum

长花百合（Lilium longiflorum）为百合科百合属的球根植物，为琉球群岛及台湾大陆东部沿海及卫星岛的特有植物。长期以来，该物种一直被认为是自交不亲和的，但我们以前发现，在位于琉球群岛北方的基海岛的自然种群。本研究以18个自然居群的种子为材料，通过对人工自花授粉后的花粉管伸长、结实率、花的形态学特征以及AFLP标记的亲缘关系等方面的研究，阐明了从自交不亲和到亲和转变的遗传、生理和地理学特征。取得的重要成果如下：（1）在物种分布上，北方岛屿和最南端岛屿以自交亲和个体占优势;（2）自交不亲和反应不是定性的，而是定量的，3）自交亲和性在F_1代中以显性遗传为主; 4）北方自交亲和群体花粉量减少，说明自交在这些群体中占优势; 5）AFLP系统发育树分析表明，自交不亲和群体向亲和优势群体的转变在物种分布的北方和南方呈平行分布; 6）自交亲和性在F_1代中以显性遗传为主;兰屿岛最南端族群的兼容长花百合品系，在生态上与遗传上最接近的种台湾百合非常相似。

Lilium longiflorum, bulbous species of Liliaceae, is endemic to islands of the Ryukyu Archipelago and to the eastern seacoasts and satellite islands of the mainland of Taiwan. The species has long been regarded as self-incompatible, but we previously revealed that natural populations of L.longiflorum in Kikaijima Island, located in the northern part of the Ryukyu Archipelago, were dominated by self-compatible individuals. In this study, pollen tube elongation and seed set after artificial self-pollination, flower morphology and phylogenic relationships based on AFLP were investigated to clarify genetic, physiological and biogeographical features of shift from self-incompatibility to -compatibility using individuals established from seeds collected in 18 natural populations covering the entire species distribution. The important results obtained were as follows :1)Self-compatible individuals were dominant in northern islands and southernmost island in the species distribution.2)Self-incompatible reaction emerged not qualitatively but quantitatively, and not only in a style but also in aovary.3)Self-compatibility inhereted dominantly in F_1 progeny.4)Reduction in amount of pollen production in northern self-compatible populations indicated that selfing is dominant in these populations.5)Phylogenic tree based on AFLP showed that shift from self-incompatible to compatible dominant population in the species occurred parapatrically in the northern and southern parts of the species distribution.6)Self-compatible L.longiflorum strains of the southernmost populations in Lanyu Island ecologically very similar to genetically the closest species, L.formosanum.