藏东南忍冬属植物分布格局及其系统演化

藏东南是忍冬属植物种类比较丰富的地区之一,其种类约占全国的24%,世界的12%。基于对藏东南分布的忍冬属植物资源资料进行系统的整理和研究现状综述,编制了藏东南忍冬属植物1亚属4组9亚组24种1亚种6变种2变型分组分种检索表,对比分析了各个种的表型特征和分布规律及其主要影响因子,并论证了该属植物的演化与青藏高原隆升的关系。发现忍冬属植物在该区域的分布从西北部到东南部、高海拔到低海拔,其生活型呈现了由"灌木—灌木小乔木—藤本和落叶—落叶半常绿—常绿"的过渡,海拔和降水是影响该属植物在该地区分布的主要生态因素;在海拔2 000~3 500 m和年降水量800~1 200 mm之间该属植物丰富度最高;在该地区分布的4个组中,囊管组的大苞亚组、紫花亚组、短冠亚组、红花亚组、蓝果亚组、郁香亚组以及空枝组的赭黄花亚组、直管组的杯苞亚组在藏东南分布都较广,唯独只有一个缠绕亚组的忍冬组,仅出现于气候偏暖湿的墨脱、察隅及波密南部,分布较为狭窄,与该组植物在系统发育上的原始性和该地区复杂生境的"避难所"作用有关。

Distribution pattern and system evolution of Lonicera plants in Southeast Tibet

Southeast Tibet is one of the areas that have abundant Lonicera plant species, the species accountes for 24% of the total country and 12% of the total world. Based on systematical collation of Lonicera plants resources material in Southeast Tibet, the present situation was summarized. We created the brief identification tables on a sections and species level of 24 species and 1 subspecies and 6 varieties, which belonged to 1 subgenus and 4 sections and 9 subgroups, comparatively analyzed the phenotypic traits, the law of distribution and main impact factors and demonstrated the relationship between the evolution of this genus and uplift of the Qinghai Tibet Plateau. We found that the distribution of Lonicera plants in this region appeared to its life-form, showing the transition of Shrub-shrub and small trees-liana, defoliation-half aiphyllus-evergreen, with elevation from low to high, the northwest to the southeast. And elevation and precipitation were the the main ecological factors that impacted the distribution of this genus in the region. Under the climatic conditions of altitude of 2 000 -3 500 m, annual precipitation of 800-1 200 mm, its richness was the highest. In the 4 groups of Lonicera plants in this area, Subsect. Bracteatae, Subsect. Purpurascentes, Subsect. Alpigenae, Subsect. Rhod -anthae, Subsect. Caeruleae and Subsect Fragrantissimae of Sect. Isika, Subsect. Ochranthae of Sect. Coeloxylosteum and Subsect. Cupulatae of Sect. Isoxylosteum were widely distributed in Southeast Tibet. The distribution of Sect. Nintooa which had only one Subsect. Volubilis was narrow that only distributed in the warmer and wetter Medog, Bome, southern of Zay, andthis was relative to its primitiveness in phylogeny and the effect of refuge in the complex habitat.