云南种子植物区系地理成分分布格局及其意义

Distribution Patterns of Genera of Yunnan Seed Plants with References to Their Biogeographical Significances

以覆盖云南全境的31个地区植物区系研究报告为基础，使用Arcview软件制作了14个种子植物属的地理成分多度分布图。对这些种子植物属的多度分布格局进行分析，获得以下结果：①热带成分合计占所统计的地区植物区系属的29.6％～94.1％，其最小值是在云南西北部，最大值出现在云南南部；温带成分合计占所统计的地区植物区系属的6％～70.4％，其多度分布恰与热带成分相反。②在热带成分中，全热带分布属占13.64％～46％，居热带成分之首，其最大值出现在云南怒江和元江的干热河谷；热带亚洲分布属占3.33％～42.26％，最大值出现在云南南部。⑧在温带成分中，北温带分布属占所统计的地区植物区系的2％～30.39％，居温带成分之首，最大值出现在云南西北部山地，其次是东亚分布属，占2％～14.57％，最大值出现在滇西北横断山区。（少在与云南植被的关系上，热带亚洲分布属、旧世界热带分布属和热带亚洲至热带大洋洲分布属是云南热带森林的主要成分；全热带分布属和热带亚洲至热带非洲分布属是干热河谷植被的主要成分，北温带分布属主要出现在冷湿山地森林植被中，而东亚分布属、东亚和北美洲间断分布属及旧世界温带分布属与温凉气候地区的森林植被联系相对密切。⑤生物地理上，云南种子植物属的多度分格局暗示了所谓的“田中线”在印度—马来西亚热带植物区系与东亚亚热带—温带植物区系的地理界限上有意义；热带亚洲至热带非洲分布属主要存在于云南的干热河谷，暗示了干热河谷植被具有一定非洲亲缘；云南西部的热带性很强，暗示了在印度板块同亚洲板块相撞、推挤北移及喜马拉雅隆升过程中，云南西部至东南部的地块可能发生了顺时针转动。⑥在云南，不论其纬度，只要是海拔低的区域都是热带区域，支持云南应是一个基带为热带的大的山原观点。

A total of 31 regional floras that covered whole Yunnan province were used for making frequency maps of distribution types at generic level by Arcview software. The following results were given-1. Tropical genera account for 29.6% to 94.1% of the total genera in regional floras with the highest proportion in the areas of southern Yunnan, while temperate genera account for 6% to 70.4% of the total genera with the highest proportion from the area of northwestern Yunnan. 2. Among tropical elements, the genera of Pantropical distribution contribute from 13.64% to 46% of the total genera in regional floras with the highest proportion in dry and hot valleys in western and southeastern Yunnan, and the genera of Tropical Asian distribution contribute from 3.33% to 42.26% with the highest proportion in southern Yunnan. 3. Among temperate elements, the genera of North temperate distribution contribute from 2% to 30.39% of the total genera in regional floras with the highest proportion in northwestern Yunnan, and the ones of East Asian distribution contribute from 2% to 14.57% with the highest proportion in Hengduan Mountains in northwestern Yunnan. 4. In relationship with vegetations of Yunnan, the genera of Tropical Asia, Old world tropics and Tropical Asia to Australia distributions occur mainly in the tropical forests in southern Yunnan ; the genera of Pantropical and Tropical Asia to Tropical Africa distributions occur mainly in the vegetations on dry and hot valleys; the genera of North temperate distribution occur mainly in forests on mountains with a cold and wet climate, while the genera of East Asian, East Asian and North America disjunct, and Old world temperate distributions occur mainly in the vegetations of the area with a warm climate. 5. In biogeography, the frequent patterns of the genera of seed plants imply that the ＂Tanaka line＂ could also act as a demarcation line between the tropical Asia flora （Indo-Malaysia flora） and East Asia flora in Yunnan; the semi-savanna vegetation in the dry and hot valleys in Yunnan could have floristic affinity to savanna of Africa; the Yunnan geo-plate could have clock-wise movement by bumping of India plate during the uplift of Himalayas. It is supported that Yunnan should be a region with tropical areas as the horizontal base because almost all areas of lower elevation are tropical in nature regardless of their latitudinal location.