【作者】 韦利杰；

【导师】 孙柏年；

【作者基本信息】 兰州大学 ， 古生物学与地层学， 2006， 硕士

【摘要】 自工业革命以来,全球温度有了明显的升高,21世纪的全球变暖现象将比20世纪更加明显。大气CO₂浓度增加引起的温室效应是造成全球变暖的主要原因,因此正确认识气孔参数与大气CO₂浓度的相关性,有助于正确预测全球气候变化的趋势。 本文研究了产于云南腾冲上新统芒棒组在外形上相似的四种被子植物化石,它们是油丹（Alseodaphne hainanensis Merr.）,小叶木姜子（Litsea grabaui Hu et Chaney）,薄叶润楠（比较种）（Machilus cf.leptophylla Hand.-Mazz.）,长叶木兰（Magnoliapaenetalauma Dandy）,这四种植物化石在滇西地区均为首次发现。对它们进行了大量的实验分析,揭示了其表皮微细构造特征。这四种植物化石的表皮微细构造特征明显不同,进一步说明了表皮微细构造特征在分类学上的意义。扫描电镜的应用,为被子植物的分类提供了准确而细微的叶表皮特征。 化石Alseodaphne hainanensis地理分布区的扩大和地质时代的延伸,说明滇西地区上新世的气候比现在温暖。自上新世至现代,滇西地区海拔升高,温度降低,致使现生Magnolia paenetalauma退出云南,这进一步表明滇西地区自上新世至现代气候逐渐变冷。化石Machilus cf.leptophylla的角质层和叶结构特征与现生Machilus leptophylla的对比,显示出化石Machilus cf.leptophylla生长在湿润气候条件下。研究表明云南腾冲上新世时是温暖湿润气候。 选择现生Alseodaphne hainanensis和Machilus leptoplla作为最近现存亲缘种,并对其进行了气孔参数统计,进而与化石种进行比较,应用气孔比率法恢复了云南腾冲上新世的大气CO₂浓度（分别是417.6ppmv和438ppmv）,二者均落在了GEOCARBⅢ的误差范围内。恢复这一时期的古环境,对了解全球环境变化具有重要的意义。更多还原

【Abstract】 Global temperature has clearly increased since the Industrial Revolution. The phenomenon of global warming is more obvious in the 21st Century than in the 20th Century. Greenhouse effect owing to atmospheric CO₂ enrichment is a great cause of global warming. Accordingly, understanding the relation between stomatal parameter and atmospheric CO₂ concentration is advantageous to predicting global climate trend.Four angiosperm fossil leaves having resemblance in appearance were studied in this work. They are Alseodaphne hainanensis Men., Litsea grabaui Hu et Chaney, Machilus cf. leptophylla Hand.-Mazz. and Magnolia paenetalauma Dandy, which were collected from the Pliocene Mangbang Formation in Tengchong, Yunnan Province, where the four fossil leaves were found for the first time. The epidermal microstructures of these species were investigated based upon extensive experiments in laboratory. The epidermal characteristics of the four plant fossils are different obviously, which shows the significances of epidermal characteristics in taxa to a great extent. The application of a scanning electronic microscopy provides exact and fine diagnosis for the classification of angiosperm.The enlargement of geographical distribution and the extension of geological age of fossil Alseodaphne hainanensis indicate that Pliocene climate was warmer than present-day in the area of Western Yunnan. Altitudinal increase and the decrease of temperature in the area of Western Yunnan have make modern Magnolia paenetalauma retreat from Yunnan, which further demonstrates that the temperature gradually decreased from Pliocene to present in the area of Western Yunnan Province. A detailed comparison of the cuticle and the leaf architecture between fossil Machilus cf. leptophylla and modern Machilus leptophylla reveals that fossil Machilus cf. leptophylla grew in humid climate. The result shows that Pliocene climate is warm and humid in Tengchong, Yunnan Province.Selecting modern Alseodaphne hainanensis and Machilus leptophylla as Nearest Living Relative species respectively and counting their stomatal parameter, we try to reconstruct Pliocene CO₂ concentration of Tengchong in Yunnan Province with Stomatal Ratio. The two data （Alseodaphne hainanensis 417.6ppmv and Machilus leptophylla 438ppmv） all fall into the error scope of revised GEOCARB III. Palaeoenvironmental reconstruction in the time has a profound significance for understanding global environmental change.更多还原