排序方式： 共有2条查询结果，搜索用时 0 毫秒
1
1.
孢粉稳定碳同位素研究进展 总被引：2，自引：0，他引：2
由于植物的光合作用途径不同,C3和C4植物的δ13C值有明显不同的分布范围,这可以用来研究环境的变化。花粉的碳同位素分析结果显示其δ13C值与植物的δ13C值变化规律一致,也能很好地反映植物的光合作用途径,进而间接反映其所处的气候环境条件。相比于植物体,化石花粉颗粒组成成分较单一,而其生成时间短,因而其碳同位素或许能较好地反映植物开花期时的环境条件,如雨水、大气CO2等的性质,为更精确的环境重建提供可能。初步的研究结果也显示花粉的δ13C值与开花期的温度存在线性关系。高精度结果的取得依赖于实验技术和仪器设备的改进,研究表明传统孢粉的醋酸酐处理过程中存在碳同位素污染,采用浓H2SO4浸泡可达到相同的去除纤维素的目的而避免污染。另外,通过对质谱仪的改进——装配旋转镍丝等进样系统(SWiM-IRMS),使实验所需的测试量大大减少,对单粒花粉进行测定也已经成为可能,但实验的精度还待进一步提高。 相似文献
2.
Experiments were carried out on the thermal decomposition of sporopollenin, isolated from a marine algae (Lycopodium clavatum) at constant temperature (380°C) and pressure (around 200 atm), but for varying pyrolysis times.The decomposition products were separated into groups, analysed by chromatography and infra-red spectroscopy, and their elemental composition determined. The thermal evolution of sporopollenin proceeds in three distinct steps: first, a partial decomposition of the initial substance occurs with the formation of soluble materials. This is followed by a full decomposition of the sporopollenin and disappearance of the non-soluble residue. Finally, a non-soluble material reappears. It is proposed that, due to secondary reactions, the evolution of kerogen of the sapropelic type is similar to what has been observed in mild pyrolysis experiments. 相似文献
1