横断山区苹果属植物区系地理学研究

Studies on the Flora of the Genus Malus Mill. in Hengduan Mountainous Region

古地中海退却与喜马拉雅-横断山的隆起,对苹果属植物区系的发展具有重要影响。采用系统发生-植物地理学的理论和方法,研究横断山区苹果属植物区系的起源和演化。结果表明,老挝海棠的小果类型通过云南南部河谷流域往北传播到横断山区,由宿萼类型演化成滇池海棠系的种类;由脱萼类型演化成陇东海棠系的种类。横断山区苹果属植物区系演化的特点是历史时期长,种类多,既有种类间小的间断分化,又有组、系间大的间断分化。该区系具有明显的演化中心和辐射状的现代分布格局,揭示了物种间的亲缘关系、空间关系、时间关系等三维关系间的密切联系。横断山区苹果属植物虽然种类多,但不是原始种的分布地,因此该地区是苹果属植物的演化中心,而不是起源中心。

Both the shrinkage of ancient Mediterranean Sea and the ridge between the Himalayas-Hengduan mountain have an important effect on the development of the flora of the Malus Mill. The origin and development of the flora of the Malus Mill. in Hengduanshan mountain were discussed with the theories and methods of systematics and phytogeography. The result indicated that the small fruit types of M.laosensis Chev. was transmitted to Hengduan mountainous district from the southern part of Yunnan by river valley. During this process, Ser. yunnanense Rehd. was evolved from permanent calyx, and Ser. kansuensis(Batal.)Schneid. was evolved from decalyx , too. The evolving features of the flora of the Malus Mill. in Hengduan mountain were: (1) the long-lasting history; (2) the many types; and (3) the differential among types. Furthermore, the flora of the Malus Mill. in Hengduan mountain which had the distinctive evolution center and the radiating distribution, demonstrates the flora of the genus Malus Mill. in Hengduan mountainous region had a rich types, but it is not the area where origin species don’t appear. So it is an evolution center of the Malus Mill., not an origin center.