C_4植物的出现与全球环境变化

C4 光合作用途径 (C4 植物 )的出现和随后的扩展 ,是发生在新生代晚期的重大事件。这一事件是晚新生代全球环境演化的产物。C4 植物在某些生态系统中占据主导地位 ,又通过食物链 ,影响了动物 ,特别是食草动物的演化。以C4 植物为主的干草原环境甚至与人类的起源有着某种成因上的联系。C4 植物的出现对中新世以来全球环境变化和现代环境格局形成过程具有特殊的意义。文中就C4 植物出现和扩展的时间、C4 植物的分布和生态特征、C4 植物出现的环境背景、构造运动 ,特别是印度和欧亚板块碰撞以及由青藏高原强烈隆升引发的侵蚀作用和大气组分变化及其与C4 植物出现的联系等问题作了较为系统的综述。文章还介绍了中国北方现代草本植物的δ13 C值的最新研究结果 ,并就草本植物δ13 C值与环境参数之间可能的关系进行了初步讨论。

APPEARANCE OF C4 PLANTS AND GLOBAL CHANGES

Occurrence of C 4 photosynthetic pathway (C 4 plant) and its following expansion is one of the most important events in the Late Cenozoic. It is closely dealing with many factors of the Earth’s environment. C 4 plants dominating some of the ecosystems cause the evolution of large herbivore mammals via food chain. The appearance of savanna, where the most species are C 4 plants, is even greatly associated with the origin of Homonidae. The occurrence of the C 4 plant therefore is of great importance in the environment change during the Late Cenozoic and in the setting up of the framework of modern environment. The paper reviews the time of the occurrence and expansion, distribution and ecological features and the environment background of the C 4 plants, the tectonic movement, especially the collision between India and Eurasia plates resulting in the uplift of Qinghai-Xizang plateau, rapidly increase of erosion and then lowering down the atmospheric CO 2. It also introduces the new measurement of δ 13 C of modern herbage in northern China, and briefly discusses the relationship of δ 13 C values and the main climatic parameters such as temperature and precipitation.