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兰州盆地古近系发现一被子植物压型化石群,对其中的山杨(PopulusdavidianaDode)做了细致的角质层分析.同时,比较了不同生境下(湿润、半湿润、半干旱至干旱气候区)现生山杨的表皮构造.实验表明,随着植物分布区纬度逐渐增高,气候从湿润到干旱、年降水量从大到小,年均温度从高到低的变化,成熟的山杨叶片明显表现出外形由大到小逐渐减缩、角质层由很薄到较厚、表皮细胞垂周壁从模糊到清晰的特点.化石山杨与处于温带半干旱-干旱气候区的山丹标本相差较远,而与温带半湿润区的武山标本最接近.新的研究反映当时植物可能生长于半湿润的气候环境.当前古近系杨属叶化石角质层的分析,对了解青藏高原隆升初期对周缘植被类型和古气候的影响具有重要意义.
In the Paleogene of Lanzhou Basin, an angiosperm-fossil community was found, and the Populus davidiana Dode was carefully analyzed for its stratum corneum.At the same time, the effects of different habitats (humid, semi-humid, semi-arid to arid climate) Epidermis structure of Populus euphratica.Experiments show that as the latitude of plant distribution area increases gradually, the climate changes from humid to arid, the annual precipitation from high to low, the average annual temperature from high to low, the mature poplar leaves obvious Showing a gradual reduction in shape from large to small, the stratum corneum from thin to thick, epidermal cells from the fuzzy wall to the clear features of the fossil aspen and temperate semi-arid - arid climatic area far away from the specimen, Which is the closest to the Wushan specimens in the temperate and semi-humid regions.The new study shows that the plants may grow in a semi-humid climatic environment at present.At present, The type and palaeoclimate influence is of great importance.