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正构烷烃是植物类脂的重要组成部分,主要用来维持叶片表面的水分平衡,其平均碳链长度(ACL)作为植物对水分胁迫程度的生理性反映,与植物进化程度存在表观上的联系。高等植物来源烷烃的ACL高于低等植物和水生藻类,裸子植物高于被子植物,C4植物高于C3植物,因此植物正构烷烃具备粗略的植物分类学意义,并在古环境研究中被广泛应用。在河口和海洋沉积物中主要用来判断水生低等植物和陆地高等植物的相对贡献,在古土壤中则用来区分草本/木本植物的消长变化。植物烷烃中的氢元素主要来自光合作用时吸收的环境水,其δD主要受环境条件和生物化学过程影响,但环境条件、气候状况和植被类型的影响可以在很大程度上相互抵消,使烷烃δD具有记录大气降水δD的潜力,从而可以用来重建大气降水δD并反演气候变化。
Normal paraffins are important components of plant lipids and are mainly used to maintain the water balance on the leaf surface. The average carbon chain length (ACL) as a physiological response of plants to water stress and the degree of plant evolution are apparent contact. The ACLs for alkanes in higher plants are higher than those in lower plants and aquatic algae, the gymnosperms are higher than angiosperms and the plants in C4 are higher than those in C3 plants. Therefore, plant n-alkanes have a rough taxonomic significance for plant taxonomy and are widely used in paleoenvironmental studies application. Mainly used in estuarine and marine sediments to determine the relative contribution of low-water plants to terrestrial higher plants, and in ancient soils are used to distinguish the growth and decline of herbaceous / woody plants. Hydrogen in plant alkanes comes mainly from the environmental water absorbed during photosynthesis. Its δD is mainly affected by environmental conditions and biochemical processes. However, the influence of environmental conditions, climate conditions and vegetation types can largely offset each other. Alkanes δD has the potential to record the δD of atmospheric precipitation, which can be used to reconstruct atmospheric precipitation δD and inverse climate change.