青藏高原北部戈壁区海拔变化幅度大,极端干旱、低温且大风,特殊环境条件导致该区种子植物区系组成有别于其他戈壁区.本文在野外调查的基础上,对该区种子植物组成与植物区系特征进行了分析.结果显示:(1)青藏高原北部戈壁区种子植物组成贫乏,调查中共记录种子植物17科50属69种,以灌木、半灌木及多年生草本为主;(2)该区含属、种数较多的科有:藜科、菊科、柽柳科、禾本科、豆科等,科内物种组成简单,优势物种主要有:红砂(Reaumuria songarica (Pall.) Maxim.)、驼绒藜(Ceratoides latens (J.F.Gmel.)Reveal et Holmgren)、合头藜(Sympegma regelii Bunge)、沙拐枣(Calligonum mongolicum Turcz.)、膜果麻黄(Ephedra przewalskii Stapf)、松叶猪毛菜(Salsola laricifolia Turcz.ex Litv.)等;(3)种子植物区系地理成分较为复杂,其中科的分布区类型以世界分布型占绝对优势,属的分布区类型以北温带分布及地中海区、西亚至中亚分布类型为重要成分;中国特有、戈壁区特有植物在植被组成中多为建群种或优势种;(4)与其他荒漠区相比,该区北温带分布及其变型,地中海区、西亚至中亚分布及其变型的比例达65％以上,显著高于黑戈壁地区、临近的库姆塔格沙漠及整个西北荒漠区.该区种子植物区系组成具有一定特殊性与过渡性特征.%We studied the flora and composition of plant species in the Gobi area of the northern Qinghai-Tibet Plateau.Results showed that:(1) species composition was poor,with 69 plant species,belonging to 17 families and 50 genera.Among these species,shrubs,subshrubs,and perennial plants were the main life forms.(2) Chenopodiaceae,Asteraceae,Tamaricaceae,Poaceae,and Fabaceae were the dominant families,and Reaumuria songarica (Pall.) Maxim.,Ceratoides latens (J.F.Gmel.) Reveal et Holmgren,Sympegma regelii Bunge,Calligonum mongolicum Turcz.,Ephedra przewalskii Stapf,and Salsola laricifolia Turcz.ex Litv.were the dominant species.(3) The geographical elements of the flora were complex.The distribution type of the families was predominantly Cosmopolitan,whereas total genera were dominated by North Temperate and Mediterranea,W.Asia to C.Asia.Chinese endemic species and Gobi area endemic species accounted for most of the constructive or dominant species of the Gobi area vegetation types.(4) Compared with other deserts,North Temperate and its subtypes and Mediterranea.W.Asia to C.Asia and its subtypes accounted for over 65％ of the total genera,higher than that found in the Black Gobi,Kumtag,and West-North deserts of China.The composition of the flora was particular and transitional.
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