甘肃侏罗纪植物化石角质层多元化分析

The relationship between fossil plant cuticles and environmental change has become a new academe focus in the world. Several hundred papers on stomata and CO2 have been published in important international journals including Nature and Science in recent years. According to the basic role of leave stomata between biosphere and atmosphere, cuticular researches are being used for revealing physiological relationship of plants and environment change through geological time. We take sight at such advancing edge of international academe and make an intersection study among palaeobotany, plant physiology and organic geochemistry. We investigated extant and fossil plant cuticles in Jurassic and Tertiary collected from west of China and studied their stomatal parameters, carbon isotope compositions and geochemical characters. Palaeoatmospheric CO2 concentration and palaeoenvironmental changes during Jurassic and Tertiary are discussed too..Our result shows that the stomatal density and stomatal index of Ginkgo huttonii (Sternberg) Heer collected from four beds, which are top of lower Jurassic, bottom, middle, top of middle Jurassic in Gansu province, has gradually decreasing tendency from bottom to top. Atmospheric CO2 concentration inferred from stomatal ratio is near to the curve of Berner's long-time carbon cycle model. It indicates that stomatal density and stomatal index of fossil Ginkgo in Jurassic of Gansu can be used as a reliable biological indicator to estimate palaeoatmospheric CO2. In addition, we also studied fossil angiosperm cuticles in Tertiary, Yunnan. It suggests that stomatal parameters of Ulmus harutoriensis Qishi et Huzioka and Carpinus subcordata Nathorst can indicate environmental change..We discovered that stomatal density and stomatal index of middle and upper part of Ginkgo biloba leaves distribute more stably from the experiments. Stomatal index and carbon isotope compositions of sun leaves and shade leaves of Ginkgo biloba from four directions were investigated. The result of the orientation analysis showed that stomatal density of sun leaves is bigger than that of shade leaves, and carbon isotope value of sun leaves is lower than that of shade leaves. By studying cuticular characters of sun leaves and shade leaves of modern Ginkgo collected from three different climatic areas in China (Lanzhou, Beijing and Nanjing), we found that climate had a greater infection on stomatal density than on stomatal index and CO2 concentration plays an significant effect on stomatal density among three factors (CO2 concentration, climate and leave shape). The carbon isotope composition value of Ginkgo leaves in Nanjing is biggest, which represents a warm and wet climate; and that of Lanzhou, located in an arid region, is smallest. It is significant that carbon isotope changes of Ginkgo leave aggregation from China and UK is similar to those of fossil Ginkgo during Mesozoic and Tertiary..In conclusion, fossil plants can be used as a global carbon cycle index through Phanerozoic. Cuticular analysis can make much fossil leaves become important elements of palaeoatmospheric environment databank. Stomatal parameters and carbon isotope compositions of extant and fossil Ginkgo are an excellent biological index for studying palaeoatmospheric CO2 concentration and environment change including temperature, humidity, water use efficiency etc. The study effectively forecasts a tendency of atmospheric CO2 concentration changing in the future by investigating change process and change rule of atmospheric CO2 concentration through geological time and provides significant reference for sustaining development of human society and nature. It has great significance on fields of biology, geology and environment change..

对甘肃侏罗纪植物化石角质层开展多元化分析，获取化石植物表皮气孔参数，推测古大气二氧化碳的浓度，揭示地史时期植物与环境的生理联系，进而了解全球环境变化；运用有机地球化学方法分析角质层的化学组分，查明不同化石角质层在成岩演化中的特征和作用，促进陆相生油理论的发展；深入研究角质层超微结构，为化石植物的分类和演化提供依据。