Abstract:Discussing the functioning and stability-maintaining mechanisms of terrestrial ecosystems, the adaptations and responses of plants to environmental changes, as well as water and nutrient use efficiency from the plant functional group perspective has become a major research approach in ecosystem ecology. The creation and subsequent studies of the plant functional group concept have provided an excellent research framework for investigating complex ecosystems. This paper summarizes the latest progress in researches on Plant functional groups (PFGs) of terrestrial ecosystems, introduces the evolution of the PFG concept, compares and appraises established definitions and classification methods of Plant functional groups. The relationship between PFGs and community stability, the influence of PFGs on community productivity, and the PFG-environment dynamics are discussed in depth. The research materials reviewed in this paper shows that PFG concept groups plant species into distinct clusters according to similarities in their functions and responses to environmental conditions. However, Plant functional characteristics are far from absolute and simple; therefore different definitions and classification methods of PFGs exist. Many researchers have studied Plant functional types from different perspectives and on varying scales. Focused on differing topics, these studies are designed to answer a wide range of scientific questions in relation with PFGs. Having conducted numerous studies on PFGs and thus accumulated large amounts of relevant data, researchers working on plant functional groups and related topics all over the world now need a universal, standardized, and unequivocal research protocol. Such a protocol will allow a comprehensive integration of research projects on PFGs globally, and can provide a significant boost to future researches on PFGs and deepen our understanding of plant functional groups.