Abstract: The successive series of forest communities at Mt.Jinyun of Shichuan province are sampled and the niche's characters and dynamics of Castanopsis fargesii population are studied by the methods of Levins' niche breadth(B), Feinsing and Spears' niche breadth(PS), and Levins' and Petraitis' niche overlapping. The results show that Castanopsis fargesii population is a dominant one in the evergreen broad leaved forest, which is at the climax stage in the succession of forest communities at Mt. Jinyun. Its niche breadth is increased with the successive process of the forest community, and the utilization degree of its resource shows the shape"∧".As for the niche overlapping between Castanopsis fargesii and other 14 dominant populations of five forest communities at Mt. Jinyun, only Castanopsis fargesii population specializedly and fully overlaps with populations Castanopsis carlesii var. spinulosa, Symplocos lancifolia, Symplocos setchunensis,Elaeocarpus japonicus,Neolitsea aurata var. glauca,Lindera kwangtungensis,Gordonia acuminata, Daphniphyllum glaucescens,Cunninghamia lanceolata and Pinus massoniana in typical mixed coniferous and evergreen broad leaved forest, and with populations Castanopsis carlesii var. spinulosa, Symplocos lamcifolia and Cunninghamia lanceolata in coniferous forest.

Key words: Niche breadth, Niche overlapping, Castanopsis fargesii population, melatonin, salt stress, alleviation effect, Ca²⁺, melon (Cucumis melo)