关键词: 大肠杆菌, 大肠杆菌

Abstract:

To know the habitat of Davidia involucrate, an endanged plants in China, using the comprehensive analysis method to analyze the community characteristics and population ecology of D. involucrate Baill. The results showed that: (1) there were plenty of plants in the community. The composition of D. involucrata community was that the east Asia plants was the largest. Next was north temperate zone. The component of species had the typical transition characteristics that from the subtropics to the temperate zone. (2) The community vertical structure was simple, which composed of tree layer, shrub layer, herb layer and interlayer plant. Herb layer was better than tree layer and shrub layer. In term of life form, phanerophytes were on the top, the composition of life form was similar to that in subtropical evergreen and deciduous forest. (3) According to the age structure. It’s indicated that D. involucrata community had not yet developed into its climax. And the spatial pattern of the whole population was of clumping distribution. (4) Natural regeneration ability of D. involucrata was weak and seed germination was low. The community of D. involucrate was in a state of instable and endanged.